The application relates to a coffee machine electric control device with motor current feedback control, multi-gear coffee making and digital display functions

Abstract

The utility model relates to electronic product technical field, concretely is coffee machine electric control device with motor current feedback control, multi -gear coffee making and digital display function, including PCB circuit board and its on main control module, power module, motor drive module, current detection module, button setting module and digital display module. Main control module adopts STM32F103C8T6 type MCU, motor drive module adopts L298N chip drive coffee making motor, and current detection module real -time acquisition motor current and feedback to MCU, button setting module contains 5 touch buttons, and the coffee type such as corresponding American, latte and self -cleaning function, digital display module shows information through the drive 4 LED nixie tube of MAX7219. MCU prestore each gear current threshold, and stop motor when current over threshold, after self -cleaning button trigger, control motor operation 5 minutes self -stop, realize accurate control, multi -type making and state direct -viewing display, improve use security and convenience.

Description

Technical Field

[0001] This utility model relates to the field of electronic product technology, specifically to an electronic control device for a coffee machine with motor current feedback control, multi-level coffee making and digital display functions. Background Technology

[0002] With the popularization of coffee culture, the demand for coffee machines in homes and restaurants has evolved from basic brewing functions to a focus on multi-category coverage, high-quality and stable output, and convenient operation. As the core control unit of a coffee machine, the performance of the electronic control unit directly determines the range of coffee types it can produce, the consistency of its taste, and the user experience. It must meet the diverse needs of different coffee categories such as Americano, Latte, Cappuccino, and Espresso, requiring different grind sizes and brewing times. It also needs precise motor control to avoid over-grinding and uneven concentration during brewing, while providing clear operational feedback to lower the barrier to entry for users. Currently, coffee machine electronic control units on the market lack a complete solution in terms of parameter targeting for multi-category compatibility, precise motor control logic, and intuitive feedback of operational status. This makes it difficult to fully meet users' dual demands for coffee quality and ease of use, and there is still room for improvement in related technologies.

[0003] Based on the actual application scenarios and current technological status of existing coffee machine electronic control devices, their core shortcomings mainly focus on the following three aspects:

[0004] 1. Insufficient adaptability across multiple price ranges, making it difficult to cover the needs of niche coffee categories.

[0005] Most existing coffee machine control systems only offer 2-3 basic function settings (such as regular coffee and espresso). These settings are crudely defined and lack specific parameter design. On the one hand, they cannot adapt to the differentiated needs of sub-categories such as Americano (requires coarse grind and short brew), cappuccino (requires medium grind and appropriate milk foam ratio), and espresso (requires fine grind and long brew). Users who want to make different flavors of coffee need to replace the grinder or manually adjust the equipment, which is cumbersome. On the other hand, some control systems that claim to have multiple settings simply adjust the motor speed for each setting without designing specific control parameters for the core needs of different coffees (such as grind size and brewing pressure). This results in minimal differences in taste between coffees made at different settings, making the multiple settings merely a formality and failing to truly meet users' needs for making specific coffee categories.

[0006] 2. The motor control lacks precise feedback, resulting in poor accuracy and stability in coffee brewing.

[0007] Current coffee machine electronic control devices mostly use fixed-time control or manual trigger stop logic to control the grinding / brewing motors, lacking a real-time load feedback mechanism.

[0008] When using fixed time control, the motor runs for a preset duration (e.g., grinding for a fixed 30 seconds). However, if the coffee beans have different hardness (e.g., the difference in hardness between dark roast and light roast beans) or there is slight residue in the grinding components, the degree of grinding will vary significantly within the same time period: hard coffee beans may be ground too coarsely, resulting in insufficient coffee concentration, while soft coffee beans may be ground too finely, causing the motor to stall.

[0009] When manually triggering the stop, the user relies on observing the coarseness of the coffee powder or their taste experience to judge when to stop. This results in a large human error, poor consistency in coffee quality between different batches made by the same user and between different users, and difficulty in ensuring a stable taste output. It is especially unsuitable for the standardized coffee making needs of catering scenarios.

[0010] 3. The operation status feedback is not intuitive, and the user threshold is high.

[0011] The status feedback functions of existing coffee machine electronic control devices are generally simplified: some low-end models only use a single indicator light to show whether the machine is on or off, making it impossible for users to determine whether the machine is working or stopped, which can easily lead to accidental start-up or long waiting times; some mid-range models can display the speed settings, but they mostly use symbols without clear text or numerical correspondences, requiring users to memorize the relationship between symbols and speed settings, which is especially unfriendly to novice users and can easily lead to incorrect coffee preparation due to misjudging the speed setting; in addition, existing devices do not provide clear feedback on both the working status and the current speed setting simultaneously, requiring users to pay attention to multiple indicators to confirm the current operating status of the machine, resulting in poor operational convenience. Utility Model Content

[0012] The purpose of this invention is to provide an electrical control device for a coffee machine with motor current feedback control, multi-level coffee making, and digital display functions, in order to solve the problem mentioned in the background art that existing analog systems and modern IP network systems cannot communicate directly due to differences in protocols and interfaces.

[0013] To achieve the above objectives, this utility model provides the following technical solution:

[0014] The coffee machine electronic control device, which features motor current feedback control, multi-level coffee making and digital display functions, includes a PCB circuit board and a main control module, power supply module, motor drive module, current detection module, button setting module and digital display module soldered on the PCB circuit board.

[0015] The main control module uses an STM32F103C8T6 MCU chip U5, whose VDD pin, which supplies 3.3V power, is connected to the 3.3V output terminal of the power supply module, and the VSS pin is grounded.

[0016] The power module is electrically connected to the MCU chip U5, the motor drive module, the current detection module and the digital display module through copper foil lines on the PCB circuit board to provide working power.

[0017] The motor drive module uses an L298N type driver chip U6. Its ENA pin, IN1 pin, and IN2 pin are connected to the PB0, PB1, and PB2 pins of the MCU chip U5 through PCB copper foil, respectively. The OUT1 and OUT2 pins of U6 are connected to the power input terminal of the coffee making motor through PCB copper foil.

[0018] The current detection module is soldered on the PCB copper foil line between the MCU chip U5 and the motor drive module U6, and its signal output terminal is connected to the PA0 pin of the MCU chip U5 through the PCB copper foil.

[0019] The button setting module includes 5 tactile buttons K1-K5 and 5 pull-up resistors R5-R9, all of which are soldered on the PCB circuit board. The output terminals of buttons K1-K5 are respectively connected to the PA1-PA5 pins of MCU chip U5 through PCB copper foil.

[0020] The digital display module includes a MAX7219 driver chip U4 and a 4-digit LED digital tube D1, both of which are soldered onto a PCB circuit board. The DIN, CLK, and LOAD pins of U4 are connected to the PB13-PB15 pins of the MCU chip U5 through PCB copper foil, and the pins of D1 are connected to the corresponding output pins of U4 through PCB copper foil.

[0021] The MCU chip U5 pre-stores the motor current threshold for each coffee setting. When the current value collected by the current detection module is higher than the threshold, U5 controls U6 to stop driving the motor. When the self-cleaning button K5 is pressed, U5 controls the heating tube / water pump to stop and simultaneously controls U6 to drive the motor to run for 5 minutes before automatically stopping.

[0022] Preferably, the power module includes a rectifier and filter unit, a first voltage regulator unit, and a second voltage regulator unit, which are electrically connected in sequence via PCB copper foil.

[0023] The rectifier and filter unit includes a DB107S type rectifier bridge BR1 and a first capacitor C1. The AC input terminals AC1 and AC2 of BR1 are connected to an external 220V AC power interface through PCB copper foil. The DC + and - output terminals of BR1 are connected to the two ends of C1 through PCB copper foil respectively. The specification of C1 is 4.7uF / 400V, and it is soldered to the edge area of ​​the PCB circuit board.

[0024] The first voltage regulator unit includes a 78M05 chip U2, a second capacitor EC1, and a third capacitor EC2. The Vin pin of U2 is connected to the positive DC output of BR1 through PCB copper foil, and the Vout pin of U2 is connected to the 12V power supply terminal of the motor drive module U6 through PCB copper foil. The GND pin of U2 is grounded. EC1 is soldered on the PCB copper foil between the Vin pin of U2 and ground, and EC2 is soldered on the PCB copper foil between the Vout pin of U2 and ground.

[0025] The second voltage regulator unit includes an AMS1117-3V3 chip U3, a fourth capacitor EC8, and a fifth capacitor EC9. The Vin pin of U3 is connected to the Vout pin of U2 through PCB copper foil. The Vout pin of U3 is connected to the VDD pin of MCU chip U5 through PCB copper foil. The GND pin of U3 is grounded. EC1, EC2, EC8, and EC9 are soldered on the PCB copper foil between the Vin pin of U3 and ground. EC9 is soldered on the PCB copper foil between the Vout pin of U3 and ground. The model of EC1, EC2, EC8, and EC9 are all 100uF / 16V.

[0026] Preferably, the current detection module includes a sampling resistor R1, an LM358 operational amplifier U1, a current limiting resistor R2, a grounding resistor R3, and a feedback resistor R4.

[0027] The sampling resistor R1 has a specification of 0.1Ω / 2W. One end of it is connected to the OUT1 pin of the motor drive module U6 through PCB copper foil, and the other end is connected to the positive terminal of the coffee making motor through PCB copper foil, forming a series circuit.

[0028] The operational amplifier U1 is soldered to the central area of ​​the PCB circuit board. Its non-inverting input is connected to the high potential end of R1 through a 1KΩ resistor R2 connected in series with PCB copper foil. Its inverting input is grounded through a 1KΩ resistor R3 connected in series with PCB copper foil. At the same time, the inverting input is connected to the output of U1 through a 10KΩ resistor R4 connected in series with PCB copper foil. The VCC pin of U1 is connected to the 3.3V output of the power module, and the GND pin is grounded. The output of U1 is connected to the PA0 pin of the MCU chip U5 through PCB copper foil.

[0029] Preferably, the five tactile buttons K1-K5 of the button setting module all adopt a 6×6mm surface mount structure and are soldered to the edge operation area of ​​the PCB circuit board.

[0030] Pull-up resistors R5-R9 are all 1KΩ resistors in 0805 packages. One end of each resistor is connected to the output terminal of the corresponding button through PCB copper foil, and the other end is grounded through PCB copper foil. The input terminal of each button is connected to the 3.3V output terminal of the power module through PCB copper foil. The output terminal of K1 is connected to the PA1 pin of MCU chip U5 through PCB copper foil, corresponding to Americano coffee. K2 is connected to the PA2 pin, corresponding to latte coffee. K3 is connected to the PA3 pin, corresponding to cappuccino. K4 is connected to the PA4 pin, corresponding to espresso. K5 is connected to the PA5 pin, corresponding to self-cleaning.

[0031] Preferably, the MAX7219 chip U4 of the digital display module is packaged in SOP-24 and soldered on the PCB circuit board near the digital tube.

[0032] The 4-digit LED digital tube D1 adopts a common cathode surface mount structure and is soldered on the front display area of ​​the PCB circuit board. Its segment selection pins ag and dp are connected to the SEGA-SEGG and SEGDP pins of U4 one by one through the PCB copper foil. Its digit selection pins DIG0-DIG3 are connected to the DIG0-DIG3 pins of U4 one by one through the PCB copper foil.

[0033] The VCC pin of U4 is connected to the 3.3V output terminal of the power module through the PCB copper foil, the GND pin is grounded, the DIN pin is connected to the PB13 pin of the MCU chip U5, the CLK pin is connected to the PB14 pin, and the LOAD pin is connected to the PB15 pin.

[0034] A 104 capacitor C6 with a 0805 package is also soldered on the PCB. One end of C6 is connected to the VCC pin of U4, and the other end is grounded to filter out power supply noise from the digital display module.

[0035] Preferably, the L298N chip U6 of the motor drive module is packaged in a Multiwatt15 package and soldered to the power area of ​​the PCB circuit board. The PCB circuit board is provided with a 2mm×20mm aluminum heat sink at the position corresponding to U6. The heat sink is attached to the heat dissipation surface of U6 by thermally conductive silicone.

[0036] The 12V power supply pin of U6 is connected to the Vout pin of the first voltage regulator unit U2 of the power module through PCB copper foil, and the GND pin of U6 is grounded; the ENA pin of U6 is connected to the PB0 pin of MCU chip U5 through the PCB copper foil in series with the current limiting resistor R10, the IN1 pin is connected to the PB1 pin, and the IN2 pin is connected to the PB2 pin; the OUT1 and OUT2 pins of U6 are connected to the 2-pin terminal 1 and 2 of motor interface J1 through PCB copper foil, respectively. The motor interface J1 is soldered to the edge of the PCB circuit board and is used to connect an external coffee making motor.

[0037] Preferably, the PCB circuit board has a size of 100mm×80mm, is made of FR-4 material with a thickness of 1.6mm, and has a surface copper foil thickness of 35μm;

[0038] The PCB circuit board is equipped with a power interface J2, a motor interface J1, and a debugging interface J3; all interfaces are soldered to the same edge of the PCB circuit board with a spacing of not less than 5mm to avoid wiring interference.

[0039] Preferably, the rectifier and filter unit of the power module also includes a 104 capacitor C8 in a 0805 package. One end of C8 is connected to the positive DC output of the rectifier bridge BR1 through PCB copper foil, and the other end is grounded. Together with C1, they form a high- and low-frequency filter combination to filter out the voltage ripple after rectification. The type of C1 is 4.7uF / 400V.

[0040] Preferably, a buzzer alarm module is also included, which includes a 5V active buzzer BZ1 and an S8050NPN transistor Q1.

[0041] The base of transistor Q1 is connected to the PB6 pin of MCU chip U5 through a series resistor R11 on the PCB copper foil. The collector is connected to the negative terminal of buzzer BZ1, and the emitter is grounded. The positive terminal of buzzer BZ1 is connected to the Vout pin of the 5V output terminal U2 of the power module through the PCB copper foil. When MCU chip U5 detects motor overload, the PB6 pin outputs a high level, driving Q1 to conduct and BZ1 to sound an alarm.

[0042] Preferably, the main control module further includes a reset circuit, which includes a touch-sensitive reset button K6, a resistor R12, and a capacitor C9.

[0043] One end of the reset button K6 is connected to the NRST pin of the MCU chip U5 through PCB copper foil, and the other end is grounded; one end of the resistor R12 is connected to the 3.3V output terminal of the power module through PCB copper foil, and the other end is connected to the NRST pin of the MCU chip U5 through PCB copper foil; one end of the capacitor C9 is connected to the NRST pin of the MCU chip U5 through PCB copper foil, and the other end is grounded; when K6 is pressed, the NRST pin is grounded, realizing the manual reset of the MCU chip U5.

[0044] Compared with the prior art, the beneficial effects of this utility model are:

[0045] 1. Compatible with a wide variety of coffee types to meet diverse needs.

[0046] (1) Based on the technical feature of being able to produce multiple types of products with 5 settings according to demand, the electronic control device of this coffee machine has 5 function settings (Americano, Latte, Cappuccino, Espresso, Self-cleaning), covering mainstream coffee categories:

[0047] (2) Different settings correspond to different grind sizes for different coffees (e.g., fine grind for espresso and coarse grind for Americano) or brewing pressure requirements. No additional equipment or accessories are needed to achieve multiple functions in one machine, which can be adapted to the taste preferences of different users in home, restaurant and other scenarios, and solve the problem of the limitation of traditional coffee machines to a single product category.

[0048] 2. Motor current feedback control ensures high precision in coffee making.

[0049] (1) The core logic of stopping the motor when the current value exceeds the set value is based on the motor current setting. This electronic control device collects the operating current of the coffee making motor (grinding motor / brewing motor) in real time through the current detection module:

[0050] Each coffee setting has a pre-set current threshold (e.g., a higher current threshold for espresso to ensure more thorough grinding; a lower threshold for Americano to avoid over-grinding). When the motor current reaches the threshold, the main control module automatically stops the motor, precisely controlling the grinding level or brewing time to avoid problems such as weak coffee due to over-grinding or clogging due to over-grinding, ensuring consistent taste and concentration in every cup of coffee.

[0051] 3. The digital display function is intuitive and easy to operate.

[0052] Digital display results: This indicates whether the device is working and displays the current button settings. The digital display module of this electronic control device can provide real-time feedback on two key types of information:

[0053] Device status: Clearly displays ON / OFF status, allowing users to quickly determine whether the device is running and avoid accidental touches or waiting;

[0054] Coffee setting information: The selected coffee setting is displayed through numerical codes (such as 00 = Americano, 01 = Latte) or text prompts, eliminating the need to memorize complex operating logic. Even beginners can quickly get started, solving the problems of opaque operation and easy selection of the wrong setting in traditional coffee machines.

[0055] 4. Self-cleaning and automated, saving time and ensuring hygiene.

[0056] (1) Cleaning mode: The compressor stops working and the motor runs for 5 minutes before automatically stopping. The self-cleaning mode of the coffee machine's electronic control device is optimized for coffee making scenarios.

[0057] (2) After cleaning is started, the main control module automatically cuts off the power to the electric heating tube / water pump of the coffee machine and drives the motor to run for 5 minutes. The motor drives the cleaning liquid in the grinding components or pipeline to flow and flush away residual coffee grounds and oil.

[0058] (3) The motor will stop automatically after 5 minutes, without the need for manual timing or intervention by the user. This saves cleaning time and avoids the growth of bacteria from residual coffee grounds, ensuring the hygiene and safety of subsequent coffee making.

[0059] 5. Automated operation reduces human error.

[0060] Compared to traditional coffee machines that require manual control of grinding / brewing time, this electronic control device achieves full automation through automatic motor shutdown via current feedback and preset gear parameters.

[0061] Users only need to select the target coffee setting, and the device can complete the entire process of motor start-up → real-time current monitoring → automatic shutdown upon reaching the standard based on the pre-stored parameters. There is no need to manually determine when to stop grinding / brewing, which greatly reduces human error. Even non-professionals can make coffee that meets the standards.

[0062] 6. Contains motor protection function, extending equipment life.

[0063] The logic of stopping the motor when the current exceeds a set value extends the advantages of device protection:

[0064] If the motor experiences an abnormally high current due to blockage of the grinding components or excessive load, the main control module can trigger a shutdown protection mechanism to prevent the motor from burning out due to prolonged overload, reduce the probability of equipment failure, and extend the overall lifespan of the coffee machine. Attached Figure Description

[0065] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are explained in detail together with the embodiments of the present invention, but do not constitute a limitation thereof.

[0066] Figure 1 This is the circuit schematic diagram of this utility model;

[0067] Figure 2 This utility model Figure 1 One of the enlarged images in the picture;

[0068] Figure 3 This utility model Figure 1 The second enlarged image in the text;

[0069] Figure 4 This utility model Figure 1 The third enlarged image in the document. Detailed Implementation

[0070] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0071] Example 1: Making a Latte

[0072] This embodiment describes in detail the complete process of a user making a latte using the electronic control device, demonstrating its core current feedback control function.

[0073] 1. Process Description:

[0074] When the user connects the coffee machine to the power supply, the power module starts working, converting 220V AC power into stable 5V and 3.3V DC power to power the entire system. The main control chip (STM32F103C8T6) initializes, and the digital display module shows the default status OFF and the default setting 00 (Americano).

[0075] The user presses the K2 button (latte coffee setting) in the button setting module. The main control module detects that the PB10 pin goes low, recognizing it as a latte coffee command. The digital display module updates the setting to 01 and recalls the pre-stored latte coffee current threshold of 1.8A.

[0076] The main control module sends a high-level start signal to the motor drive module via the PB12 pin, activating the motor drive circuit and starting the grinding motor to grind coffee beans. The sampling resistor R1 (0.1Ω) in the current detection module converts the motor current into a voltage signal in real time. This signal is amplified by a non-inverting amplifier circuit composed of an LM358 operational amplifier (gain of 1 + R4 / R3 = 11 times) before being sent to the ADC pin of the main control module.

[0077] The main control module internally performs ADC sampling and converts the voltage value back into the actual current value. In the initial grinding stage, with more coffee beans, the resistance is greater, resulting in a higher current. As grinding progresses, the current gradually decreases and stabilizes. When the coffee grounds are about to fill the hopper, the grinding resistance increases sharply, causing the motor operating current to rise rapidly. When the main control module detects that the real-time current value exceeds the set 1.8A threshold, it immediately sends a stop signal to the motor drive module, and the motor stops running. The digital display module's status indicator changes to OFF, indicating that the latte has been made.

[0078] 2. Key Parameter Table:

[0079] Selected gear Latte (01) Select via button K2 Preset current threshold 1.8A Stored in the main control MCU, used to determine when grinding is complete. sampling resistor 0.1Ω / 2W Convert current signal to voltage signal Amplifier gain 11 times Calculation formula: 1 + R⁴ / R³ = 1 + 10kΩ / 1kΩ Overload protection threshold 3.0A Fault protection will be triggered if the duration exceeds 3 seconds.

[0080] Example 2: Technician adjusts parameters for different coffee settings

[0081] This example demonstrates how technicians can adjust the current threshold for each coffee setting via a UART interface to suit different coffee beans and user taste preferences.

[0082] 1. Process Description:

[0083] The technician connected the computer's USB-to-serial adapter to the UART debugging interface of the main control module (e.g., PA9, PA10 pins). They then opened a serial port debugging assistant and set the correct baud rate (e.g., 9600bps).

[0084] By sending commands in a specific format, the technician can read or modify parameters stored in the main control chip's Flash memory. For example, sending the READTHRESHOLD03 command reads the current threshold for the espresso setting, returning a value of 2.2A. The technician discovered that after using coffee beans from a new region, grinding to 2.2A resulted in over-extraction and a bitter taste due to the grind being too fine. Therefore, the technician decided to change the threshold to 2.0A.

[0085] The technician sent the SETTHRESHOLD032.0 command. After receiving and verifying it, the main control module stored the new threshold of 2.0A in the corresponding storage area. To ensure system stability, the technician read the threshold values ​​for all gears sequentially and created a new parameter table.

[0086] 2. Coffee speed parameter adjustment table:

[0087] Americano 00 1.5 1.5 Maintaining the original coarse grind results in a refreshing taste. Latte 01 1.8 1.7 Slightly coarse the flavor to highlight the milky aroma. Cappuccino 02 2 2 Maintain standard grinding degree Espresso 03 2.2 2.0 Coarse grinding to avoid over-extraction and bitterness. Self-cleaning 04 2.5 (Overload) 2.5 (Overload) Protective threshold, no adjustment required.

[0088] Example 3: Executing self-cleaning function and triggering fault protection

[0089] This embodiment details the operation process of the self-cleaning function and how to trigger the fault protection mechanism through current detection in abnormal situations.

[0090] 1. Process Description:

[0091] The user noticed a decrease in the coffee machine's grinding efficiency, speculating that coffee oil and fine powder residue remained. Pressing the K5 button selected the self-cleaning mode. The digital display showed 04 and ON. The main control module first cut off the power to the electric heating element and water pump to prevent accidental activation of heating or water supply during the cleaning process.

[0092] Subsequently, the main control module starts the grinding motor and begins a 5-minute countdown. The motor idles, driving the cleaner to scrub the internal blades and channels. During this period, the current detection module operates continuously. Under normal circumstances, due to the light load, the current should remain stable at a low level (e.g., 0.5A).

[0093] Suppose that during the cleaning process, a small clumping of coffee grounds gets stuck in the burr, causing the motor to stall. The current detection module immediately detects a sharp spike in current (e.g., momentarily reaching 2.6A), exceeding the overload threshold of 2.5A for the self-cleaning mode. The main control module immediately executes the fault handling logic:

[0094] First detection of exceeding the threshold: The motor stops running for 5 seconds to attempt to dislodge the obstruction.

[0095] After 5 seconds, an attempt was made to restart: the motor started running again, but the current was still as high as 2.6A, and the jamming was still present.

[0096] Repeated pause-restart loop: The main control module records the number of restarts. After the third failed restart, it is determined to be a permanent fault.

[0097] Triggering final protection: The main control module completely stops the motor and controls the digital display module to flash the ERR indicator. Simultaneously, the buzzer connected to the PB6 pin emits a rapid beeping alarm, prompting the user to manually intervene and clear the obstruction. After the user disconnects the power, removes the obstruction, and powers on again, the device returns to normal.

[0098] 2. Self-cleaning process and troubleshooting table:

[0099] 1. Start Press K5 key Heating / water supply cut off, motor starts 040N Start 5-minute timer 2. Normal operation 0s-50s The motor runs at a constant speed. 040N Current ≈ 0.5A 3. An abnormality occurred. 51s The current rises to 2.6A > 2.5A 040N Stall detected 4. First processing 51sts The motor stopped immediately. 040N Pause for 5 seconds 5. First restart 56s Motor restart 040N The current remains at 2.6A; failure. 6. Loop processing No. 61s, 66s Repeated pause-restart 040N Three attempts were made in total. 7. Final Protection After the third failure When the motor stops, the buzzer sounds an alarm. ERR (Flickering) Users need to disconnect the power to troubleshoot.

[0100] This utility model of a coffee machine electronic control device, which features motor current feedback control, multi-level coffee brewing, and digital display, has the following advantages:

[0101] 1. Compatible with a wide variety of coffee types to meet diverse needs.

[0102] (1) Based on the technical feature of being able to produce multiple types of products with 5 settings according to demand, the electronic control device of this coffee machine has 5 function settings (Americano, Latte, Cappuccino, Espresso, Self-cleaning), covering mainstream coffee categories:

[0103] (2) Different settings correspond to different grind sizes for different coffees (e.g., fine grind for espresso and coarse grind for Americano) or brewing pressure requirements. No additional equipment or accessories are needed to achieve multiple functions in one machine, which can be adapted to the taste preferences of different users in home, restaurant and other scenarios, and solve the problem of the limitation of traditional coffee machines to a single product category.

[0104] 2. Motor current feedback control ensures high precision in coffee making.

[0105] (1) The core logic of stopping the motor when the current value exceeds the set value is based on the motor current setting. This electronic control device collects the operating current of the coffee making motor (grinding motor / brewing motor) in real time through the current detection module:

[0106] Each coffee setting has a pre-set current threshold (e.g., a higher current threshold for espresso to ensure more thorough grinding; a lower threshold for Americano to avoid over-grinding). When the motor current reaches the threshold, the main control module automatically stops the motor, precisely controlling the grinding level or brewing time to avoid problems such as weak coffee due to over-grinding or clogging due to over-grinding, ensuring consistent taste and concentration in every cup of coffee.

[0107] 3. The digital display function is intuitive and easy to operate.

[0108] Digital display results: This indicates whether the device is working and displays the current button settings. The digital display module of this electronic control device can provide real-time feedback on two key types of information:

[0109] Device status: Clearly displays ON / OFF status, allowing users to quickly determine whether the device is running and avoid accidental touches or waiting;

[0110] Coffee setting information: The selected coffee setting is displayed through numerical codes (such as 00 = Americano, 01 = Latte) or text prompts, eliminating the need to memorize complex operating logic. Even beginners can quickly get started, solving the problems of opaque operation and easy selection of the wrong setting in traditional coffee machines.

[0111] 4. Self-cleaning and automated, saving time and ensuring hygiene.

[0112] (1) Cleaning mode: The compressor stops working and the motor runs for 5 minutes before automatically stopping. The self-cleaning mode of the coffee machine's electronic control device is optimized for coffee making scenarios.

[0113] (2) After cleaning is started, the main control module automatically cuts off the power to the electric heating tube / water pump of the coffee machine (to avoid heating during cleaning and causing residual coffee to carbonize), and at the same time drives the motor to run for 5 minutes. The motor drives the cleaning liquid in the grinding components or pipeline to flow and flush away residual coffee grounds and grease.

[0114] (3) The motor will stop automatically after 5 minutes, without the need for manual timing or intervention by the user. This saves cleaning time and avoids the growth of bacteria from residual coffee grounds, ensuring the hygiene and safety of subsequent coffee making.

[0115] 5. Automated operation reduces human error.

[0116] Compared to traditional coffee machines that require manual control of grinding / brewing time, this electronic control device achieves full automation through automatic motor shutdown via current feedback and preset gear parameters.

[0117] Users only need to select the target coffee setting, and the device can complete the entire process of motor start-up → real-time current monitoring → automatic shutdown upon reaching the standard based on the pre-stored parameters. There is no need to manually determine when to stop grinding / brewing, which greatly reduces human error. Even non-professionals can make coffee that meets the standards.

[0118] 6. Contains motor protection function, extending equipment life.

[0119] The logic of stopping the motor when the current exceeds a set value extends the advantages of device protection:

[0120] If the motor current rises abnormally due to blockage of the grinding components or excessive load (such as exceeding the overload threshold), the main control module can trigger a shutdown protection (similar to an extended application of current-based shutdown) to prevent the motor from burning out due to prolonged overload, reduce the probability of equipment failure, and extend the overall lifespan of the coffee machine.

[0121] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A coffee machine electronic control device with motor current feedback control, multi-level coffee brewing, and digital display functions, characterized in that, It includes a PCB circuit board and the main control module, power supply module, motor drive module, current detection module, key setting module and digital display module soldered on the PCB circuit board; The main control module uses an STM32F103C8T6 MCU chip U5, whose VDD pin, which supplies 3.3V power, is connected to the 3.3V output terminal of the power supply module, and the VSS pin is grounded. The power module is electrically connected to the MCU chip U5, the motor drive module, the current detection module and the digital display module through copper foil lines on the PCB circuit board to provide working power. The motor drive module uses an L298N type driver chip U6. Its ENA pin, IN1 pin, and IN2 pin are connected to the PB0, PB1, and PB2 pins of the MCU chip U5 through PCB copper foil, respectively. The OUT1 and OUT2 pins of U6 are connected to the power input terminal of the coffee making motor through PCB copper foil. The current detection module is soldered on the PCB copper foil line between the MCU chip U5 and the motor drive module U6, and its signal output terminal is connected to the PA0 pin of the MCU chip U5 through the PCB copper foil. The button setting module includes 5 tactile buttons K1-K5 and 5 pull-up resistors R5-R9, all of which are soldered on the PCB circuit board. The output terminals of buttons K1-K5 are respectively connected to the PA1-PA5 pins of MCU chip U5 through PCB copper foil. The digital display module includes a MAX7219 driver chip U4 and a 4-digit LED digital tube D1, both of which are soldered onto a PCB circuit board. The DIN, CLK, and LOAD pins of U4 are connected to the PB13-PB15 pins of the MCU chip U5 through PCB copper foil, and the pins of D1 are connected to the corresponding output pins of U4 through PCB copper foil. The MCU chip U5 pre-stores the motor current threshold for each coffee setting. When the current value collected by the current detection module is higher than the threshold, U5 controls U6 to stop driving the motor. When the self-cleaning button K5 is pressed, U5 controls the heating tube / water pump to stop and simultaneously controls U6 to drive the motor to run for 5 minutes before automatically stopping.

2. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The power module includes a rectifier and filter unit, a first voltage regulator unit and a second voltage regulator unit, which are electrically connected in sequence via PCB copper foil. The rectifier and filter unit includes a DB107S type rectifier bridge BR1 and a first capacitor C1. The AC input terminals AC1 and AC2 of BR1 are connected to an external 220V AC power interface through PCB copper foil. The DC + and - output terminals of BR1 are connected to the two ends of C1 through PCB copper foil respectively. The specification of C1 is 4.7uF / 400V, and it is soldered to the edge area of ​​the PCB circuit board. The first voltage regulator unit includes a 78M05 chip U2, a second capacitor EC1, and a third capacitor EC2. The Vin pin of U2 is connected to the positive DC output of BR1 through PCB copper foil, and the Vout pin of U2 is connected to the 12V power supply terminal of the motor drive module U6 through PCB copper foil. The GND pin of U2 is grounded. EC1 is soldered on the PCB copper foil between the Vin pin of U2 and ground, and EC2 is soldered on the PCB copper foil between the Vout pin of U2 and ground. The second voltage regulator unit includes an AMS1117-3V3 chip U3, a fourth capacitor EC8, and a fifth capacitor EC9. The Vin pin of U3 is connected to the Vout pin of U2 through PCB copper foil. The Vout pin of U3 is connected to the VDD pin of MCU chip U5 through PCB copper foil. The GND pin of U3 is grounded. EC1, EC2, EC8, and EC9 are soldered on the PCB copper foil between the Vin pin of U3 and ground. EC9 is soldered on the PCB copper foil between the Vout pin of U3 and ground. The model of EC1, EC2, EC8, and EC9 are all 100uF / 16V.

3. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The current detection module includes a sampling resistor R1, an LM358 operational amplifier U1, a current limiting resistor R2, a grounding resistor R3, and a feedback resistor R4. The sampling resistor R1 has a specification of 0.1Ω / 2W. One end of it is connected to the OUT1 pin of the motor drive module U6 through PCB copper foil, and the other end is connected to the positive terminal of the coffee making motor through PCB copper foil, forming a series circuit. The operational amplifier U1 is soldered to the central area of ​​the PCB circuit board. Its non-inverting input is connected to the high potential end of R1 through a 1KΩ resistor R2 connected in series with PCB copper foil. Its inverting input is grounded through a 1KΩ resistor R3 connected in series with PCB copper foil. At the same time, the inverting input is connected to the output of U1 through a 10KΩ resistor R4 connected in series with PCB copper foil. The VCC pin of U1 is connected to the 3.3V output of the power module, and the GND pin is grounded. The output of U1 is connected to the PA0 pin of the MCU chip U5 through PCB copper foil.

4. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The five tactile buttons K1-K5 of the button setting module all adopt a 6×6mm surface mount structure and are soldered to the edge operation area of ​​the PCB circuit board. Pull-up resistors R5-R9 are all 1KΩ resistors in 0805 packages. One end of each resistor is connected to the output terminal of the corresponding button through PCB copper foil, and the other end is grounded through PCB copper foil. The input terminal of each button is connected to the 3.3V output terminal of the power module through PCB copper foil. The output terminal of K1 is connected to the PA1 pin of MCU chip U5 through PCB copper foil, corresponding to Americano coffee. K2 is connected to the PA2 pin, corresponding to latte coffee. K3 is connected to the PA3 pin, corresponding to cappuccino. K4 is connected to the PA4 pin, corresponding to espresso. K5 is connected to the PA5 pin, corresponding to self-cleaning.

5. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The MAX7219 chip U4 of the digital display module is packaged in SOP-24 and soldered on the PCB circuit board near the digital tube. The 4-digit LED digital tube D1 adopts a common cathode surface mount structure and is soldered on the front display area of ​​the PCB circuit board. Its segment selection pins ag and dp are connected to the SEGA-SEGG and SEGDP pins of U4 one by one through the PCB copper foil. Its digit selection pins DIG0-DIG3 are connected to the DIG0-DIG3 pins of U4 one by one through the PCB copper foil. The VCC pin of U4 is connected to the 3.3V output terminal of the power module through the PCB copper foil, the GND pin is grounded, the DIN pin is connected to the PB13 pin of the MCU chip U5, the CLK pin is connected to the PB14 pin, and the LOAD pin is connected to the PB15 pin. A 104 capacitor C6 with a 0805 package is also soldered on the PCB. One end of C6 is connected to the VCC pin of U4, and the other end is grounded to filter out power supply noise from the digital display module.

6. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The L298N chip U6 of the motor drive module is packaged in a Multiwatt15 package and soldered to the power area of ​​the PCB circuit board. The PCB circuit board has a 2mm×20mm aluminum heat sink at the position corresponding to U6. The heat sink is attached to the heat dissipation surface of U6 by thermally conductive silicone. The 12V power supply pin of U6 is connected to the Vout pin of the first voltage regulator unit U2 of the power module through PCB copper foil, and the GND pin of U6 is grounded; the ENA pin of U6 is connected to the PB0 pin of MCU chip U5 through the PCB copper foil in series with the current limiting resistor R10, the IN1 pin is connected to the PB1 pin, and the IN2 pin is connected to the PB2 pin; the OUT1 and OUT2 pins of U6 are connected to the 2-pin terminal 1 and 2 of motor interface J1 through PCB copper foil, respectively. The motor interface J1 is soldered to the edge of the PCB circuit board and is used to connect an external coffee making motor.

7. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The PCB circuit board measures 100mm × 80mm, is made of FR-4 material with a thickness of 1.6mm, and has a surface copper foil thickness of 35μm. The PCB circuit board is equipped with a power interface J2, a motor interface J1, and a debugging interface J3; all interfaces are soldered to the same edge of the PCB circuit board with a spacing of not less than 5mm to avoid wiring interference.

8. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 2, characterized in that, The rectifier and filter unit of the power module also includes a 104 capacitor C8 in a 0805 package. One end of C8 is connected to the positive DC output of the rectifier bridge BR1 through PCB copper foil, and the other end is grounded. Together with C1, they form a high- and low-frequency filter combination to filter out the voltage ripple after rectification. The model of C1 is 4.7uF / 400V.

9. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, It also includes a buzzer alarm module, which includes a 5V active buzzer BZ1 and an S8050NPN transistor Q1; The base of transistor Q1 is connected to the PB6 pin of MCU chip U5 through a series resistor R11 on the PCB copper foil. The collector is connected to the negative terminal of buzzer BZ1, and the emitter is grounded. The positive terminal of buzzer BZ1 is connected to the Vout pin of the 5V output terminal U2 of the power module through the PCB copper foil. When MCU chip U5 detects motor overload, the PB6 pin outputs a high level, driving Q1 to conduct and BZ1 to sound an alarm.

10. The coffee machine electrical control device with motor current feedback control, multi-level coffee brewing, and digital display functions as described in claim 1, characterized in that, The main control module also includes a reset circuit, which includes a touch-sensitive reset button K6, a resistor R12 and a capacitor C9. One end of the reset button K6 is connected to the NRST pin of the MCU chip U5 through PCB copper foil, and the other end is grounded; one end of the resistor R12 is connected to the 3.3V output terminal of the power module through PCB copper foil, and the other end is connected to the NRST pin of the MCU chip U5 through PCB copper foil; one end of the capacitor C9 is connected to the NRST pin of the MCU chip U5 through PCB copper foil, and the other end is grounded; when K6 is pressed, the NRST pin is grounded, realizing the manual reset of the MCU chip U5.

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