Strain gauge mode to prevent changes due to temperature

Abstract

Embodiments of the present disclosure relate to a strain gauge pattern that prevents changes due to temperature. The strain gauge includes a first substrate and a second substrate spaced apart from each other. A first flexible printed circuit board portion contacts the top sides of the first substrate and the second substrate and has a first Wheatstone bridge formed therein. The first flexible printed circuit board portion positions the first Wheatstone bridge so that two resistors in the first Wheatstone bridge are positioned to span from the top side of the first substrate to the top side of the second substrate. A second flexible printed circuit board portion contacts the bottom sides of the first substrate and the second substrate and has a second Wheatstone bridge formed therein. The second flexible printed circuit board positions the second Wheatstone bridge so that two resistors in the second Wheatstone bridge are positioned to span from the bottom side of the first substrate to the bottom side of the second substrate.

Description

Technical Field

[0001] The present disclosure relates to the field of strain gauge sensors, and in particular to a strain gauge sensor formed from a pattern of resistors that provides the strain gauge sensor with the ability to provide consistent readings over a range of operating temperatures. Background Art

[0002] Touch screens are widely used in smart phones, smart watches, tablet computers and notebook computers. Touch screens are typically formed in a layered manner, where a display layer (for displaying content and prompting user input) is covered by a touch matrix that uses capacitive sensing to receive the user input.

[0003] In some cases, it may be desirable for a certain area of ​​the touch screen to be sensitive not only to touch itself, but also to the pressure of the touch. For example, this can be used to provide a "virtual" home button or volume control button or AI key, for example, without using a physical button, which would consume the area on the top, left or right side of the device that could otherwise be occupied by the touch screen. To facilitate this functionality, strain gauges can be incorporated into the touch screen. It is hoped that by replacing physical buttons, the device design can be improved.

[0004] The double-sided strain gauge 2 of the sample is Figure 1A is shown in and Figure 1B , where it can be seen that the double-sided strain gauge 2 comprises a Wheatstone bridge 4 formed in a flexible printed circuit board (FPCB) 5 that is bent around two spaced-apart substrates 3a and 3b. The double-sided strain gauge 2 can be positioned in any suitable or desired device.

[0005] The Wheatstone bridge 4 includes resistors R1 and R2 positioned adjacent to the upper surfaces of the substrates 3a and 3b, and resistors R3 and R4 positioned on the lower surfaces of the substrates 3a and 3b. Note that the resistors R1 to R4 are all positioned so as to extend across the space 4 between the substrates 3a and 3b so that the FPCB 5 and its Wheatstone bridge 4 can deform under stress.

[0006] The electrical connections of the Wheatstone bridge 4 are Figure 1B Here, it can be seen that for the Wheatstone bridge 4, the resistors R1 and R4 are connected in series between the voltage Vs and the ground GND through the node p1, the resistors R3 and R2 are connected in series between the voltage Vs and the ground GND through the node n1, and the series-connected resistors R1 and R4 are connected in parallel with the series-connected resistors R3 and R2. The nodes p1 and n1 provide outputs for the bridge 4.

[0007] When a physical force is applied to the top of the double-sided strain gauge 2 in the downward direction, the FPCB 5 is deformed, so that the strain on the resistors R1 and R2 changes relative to the strain on the resistors R3 and R4. The result is a change in the resistance of the resistors R1 and R2 relative to the resistance of the resistors R3 and R4, and a voltage differential is formed between the nodes p1 and n1, so that the voltage Vp1-Vn1 is measurable, and based on the voltage, the direction of the force applied to the double-sided strain gauge 2 and the magnitude of the force can be determined. In the case of a touch with a negligible physical force, a minimum voltage differential is formed between the nodes p1 and n1, so that the voltage Vp1-Vn1 is negligible; therefore, at normal temperature, the double-sided strain gauge 2 is able to distinguish between a touch with a physical force and a touch with a negligible physical force.

[0008] In normal temperature range, this design of double-sided strain gauge 2 usually works correctly. Figure 1C to Figure 1D As shown, problems may occur at temperatures outside the normal range of operating temperatures (such as extremely cold or hot conditions).

[0009] Under these conditions, regardless of whether the FPCB 5 is bent (and therefore, regardless of whether the touch is a touch with pressure or a touch with only contact without pressure), the voltage differential between the points p1 and n1 is measurable and similar because the temperature difference between the user's finger and the ambient temperature of the double-sided strain gauge 2 is sufficient to cause the voltage differential. Therefore, outside the normal operating temperature range, the double-sided strain gauge 2 may not be able to distinguish between a touch with negligible physical force and a touch with physical force, making the double-sided strain gauge 2 unusable for most of its intended uses (e.g., detecting a touch with a physical force).

[0010] Therefore, further development in this area is needed. Summary of the invention

[0011] The present invention discloses an electronic device including a strain gauge. The strain gauge includes: a substrate layer including a first substrate and a second substrate located in the same plane but spaced apart from each other; a flexible printed circuit board including a first Wheatstone bridge and a second Wheatstone bridge, the flexible printed circuit board being wrapped around the end of the substrate layer so that the flexible printed circuit board is in contact with both the top sides of the first substrate and the second substrate and the bottom sides of the first substrate and the second substrate. The flexible printed circuit board positions the first Wheatstone bridge so that the two resistors in the first Wheatstone bridge are positioned so that the two resistors span from the top side of the first substrate to the top side of the second substrate, and the remaining resistors in the first Wheatstone bridge are positioned only on the top side of the first substrate. The flexible printed circuit board positions the second Wheatstone bridge so that the two resistors in the second Wheatstone bridge are positioned so that the two resistors span from the bottom side of the first substrate to the bottom side of the second substrate, and the remaining resistors in the second Wheatstone bridge are positioned only on the bottom side of the first substrate.

[0012] The electronic device may include a strain gauge controller configured to: measure a voltage difference between a first output and a second output of a first Wheatstone bridge; measure a voltage difference between a first output and a second output of a second Wheatstone bridge; and determine a voltage differential between the first Wheatstone bridge and the second Wheatstone bridge as a difference between a voltage difference for the first Wheatstone bridge and a voltage difference for the second Wheatstone bridge.

[0013] The strain gauge controller may be configured to determine a magnitude and direction of a force applied to the strain gauge based on the determined voltage differential between the first Wheatstone bridge resistor and the second Wheatstone bridge resistor.

[0014] The first Wheatstone bridge and the second Wheatstone bridge may be coupled between a supply voltage and ground.

[0015] The first Wheatstone bridge may be formed by at least the following items: a first resistor positioned so as to span from the top side of the first substrate to the top side of the second substrate; a second resistor positioned so as to be positioned only on the top side of the first substrate; a third resistor positioned so as to span from the top side of the first substrate to the top side of the second substrate; and a fourth resistor positioned so as to be positioned only on the top side of the first substrate. The first resistor and the second resistor may be coupled in series between a power supply voltage and ground, wherein a first output of the first Wheatstone bridge is electrically connected between the first resistor and the second resistor. The third resistor and the fourth resistor may be coupled in series between a power supply voltage and ground, wherein a second output of the first Wheatstone bridge is electrically connected between the third resistor and the fourth resistor.

[0016] The first resistor and the fourth resistor are physically positioned parallel to each other, and the second resistor and the third resistor are physically positioned parallel to each other.

[0017] The second Wheatstone bridge is formed by at least the following items: a fifth resistor, positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate. A sixth resistor, positioned so as to be positioned only on the bottom side of the first substrate; a seventh resistor, positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; and an eighth resistor, positioned so as to be positioned only on the bottom side of the first substrate. The fifth resistor and the sixth resistor are coupled in series between the power supply voltage and ground, wherein the first output of the second Wheatstone bridge is electrically connected between the fifth resistor and the sixth resistor. The seventh resistor and the eighth resistor are coupled in series between the power supply voltage and ground, wherein the second output of the second Wheatstone bridge is electrically connected between the seventh resistor and the eighth resistor.

[0018] The sixth resistor and the seventh resistor are physically positioned parallel to each other, and wherein the fifth resistor and the eighth resistor are physically positioned parallel to each other.

[0019] Another aspect of the present disclosure provides a strain gauge, comprising: a substrate layer, comprising a first substrate and a second substrate spaced apart from each other; and a first flexible printed circuit board portion, contacting the top sides of the first substrate and the second substrate, the first flexible printed circuit board portion having a first Wheatstone bridge formed therein; wherein the first flexible printed circuit board portion positions the first Wheatstone bridge so that two resistors in the first Wheatstone bridge are positioned so that the two resistors span from the top side of the first substrate to the top side of the second substrate; and a second flexible printed circuit board portion, contacting the bottom sides of the first substrate and the second substrate, the second flexible printed circuit board portion having a second Wheatstone bridge formed therein; wherein the second flexible printed circuit board positions the second Wheatstone bridge so that the two resistors in the second Wheatstone bridge are positioned so that the two resistors span from the bottom side of the first substrate to the bottom side of the second substrate.

[0020] According to one or more embodiments, the first Wheatstone bridge and the second Wheatstone bridge are coupled between a power supply voltage and ground.

[0021] According to one or more embodiments, the first Wheatstone bridge includes: a first resistor, which is positioned so as to span from the top side of the first substrate to the top side of the second substrate; a second resistor, which is positioned so as to be positioned only on the top side of the first substrate; a third resistor, which is positioned so as to span from the top side of the first substrate to the top side of the second substrate; and a fourth resistor, which is positioned so as to be positioned only on the top side of the first substrate; wherein the first resistor and the second resistor are coupled in series between a power supply voltage and ground, wherein a first output of the first Wheatstone bridge is electrically connected between the first resistor and the second resistor; and wherein the third resistor and the fourth resistor are coupled in series between the power supply voltage and ground, wherein a second output of the first Wheatstone bridge is electrically connected between the third resistor and the fourth resistor.

[0022] According to one or more embodiments, wherein the first resistor and the fourth resistor are physically positioned parallel to each other; and wherein the second resistor and the third resistor are physically positioned parallel to each other.

[0023] According to one or more embodiments, the second Wheatstone bridge includes: a fifth resistor, positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; a sixth resistor, positioned so as to be positioned only on the bottom side of the first substrate; a seventh resistor, positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; and an eighth resistor, positioned so as to be positioned only on the bottom side of the first substrate; wherein the fifth resistor and the sixth resistor are coupled in series between a power supply voltage and ground, wherein a first output of the second Wheatstone bridge is electrically connected between the fifth resistor and the sixth resistor; and wherein the seventh resistor and the eighth resistor are coupled in series between the power supply voltage and ground, wherein a second output of the second Wheatstone bridge is electrically connected between the seventh resistor and the eighth resistor.

[0024] According to one or more embodiments, wherein the sixth resistor and the seventh resistor are physically positioned parallel to each other, and wherein the fifth resistor and the eighth resistor are physically positioned parallel to each other.

[0025] Another aspect of the present disclosure provides an electronic device, comprising: a strain gauge, comprising: a substrate layer, comprising a first substrate and a second substrate located in the same plane; a flexible printed circuit board, comprising a first Wheatstone bridge and a second Wheatstone bridge, the flexible printed circuit board being in contact with both the top sides of the first substrate and the second substrate and the bottom sides of the first substrate and the second substrate; wherein the flexible printed circuit board positions the first Wheatstone bridge so that two resistors in the first Wheatstone bridge are positioned so that the two resistors span from the top side of the first substrate to the top side of the second substrate, and so that the remaining resistors in the first Wheatstone bridge are positioned only on the top side of the first substrate; wherein the flexible printed circuit board The brush circuit board positions the second Wheatstone bridge so that the two resistors in the second Wheatstone bridge are positioned so that the two resistors span from the bottom side of the first substrate to the bottom side of the second substrate, and so that the remaining resistors in the second Wheatstone bridge are positioned only on the bottom side of the first substrate; a strain gauge controller is configured to: measure the voltage difference between the first output and the second output of the first Wheatstone bridge; measure the voltage difference between the first output and the second output of the second Wheatstone bridge; and determine the voltage difference between the first Wheatstone bridge and the second Wheatstone bridge as the difference between the voltage difference for the first Wheatstone bridge and the voltage difference for the second Wheatstone bridge.

[0026] According to one or more embodiments, the first Wheatstone bridge includes: a first resistor, positioned so as to span from the top side of the first substrate to the top side of the second substrate; a second resistor, positioned so as to be positioned only on the top side of the first substrate; a third resistor, positioned so as to span from the top side of the first substrate to the top side of the second substrate; and a fourth resistor, positioned so as to be positioned only on the top side of the first substrate.

[0027] According to one or more embodiments, wherein the first resistor and the fourth resistor are physically positioned parallel to each other; and wherein the second resistor and the third resistor are physically positioned parallel to each other.

[0028] According to one or more embodiments, the second Wheatstone bridge includes: a fifth resistor positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; a sixth resistor positioned so as to be positioned only on the bottom side of the first substrate; a seventh resistor positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; and an eighth resistor positioned so as to be positioned only on the bottom side of the first substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A Included is a side view of a prior art double-sided strain gauge subjected to a touch with force at normal operating temperature.

[0030] Figure 1B yes Figure 1A Schematic diagram of the electrical connections of a prior art double-sided strain gauge Wheatstone bridge.

[0031] Figure 1C Included is a side view of a prior art double-sided strain gauge subjected to forceless touch at extreme operating temperatures.

[0032] Figure 1D yes Figure 1C Schematic diagram of the electrical connections of a prior art double-sided strain gauge Wheatstone bridge.

[0033] Figure 2A Included is a side view of a double-sided strain gauge disclosed herein subjected to a touch with force at normal operating temperature.

[0034] Figure 2B yes Figure 2A Schematic diagram of the electrical connections of the double-sided strain gauge Wheatstone bridge.

[0035] Figure 2C Included is a side view of a double-sided strain gauge disclosed herein subjected to a forceless touch at extreme operating temperatures.

[0036] Figure 2D yes Figure 2C Schematic diagram of the electrical connections of the double-sided strain gauge Wheatstone bridge.

[0037] Figure 3 is a block diagram of an electronic device incorporating the double-sided strain gauge disclosed herein. DETAILED DESCRIPTION

[0038] The following disclosure enables those skilled in the art to make and use the subject matter disclosed herein. Without departing from the spirit and scope of the present disclosure, the general principles described herein may be applied to embodiments and applications other than those described in detail above. The present disclosure is not intended to be limited to the embodiments shown, but should be given the widest scope consistent with the principles and features disclosed or suggested herein.

[0039] Reference now Figure 2A A double-sided strain gauge 12 is described, where it can be seen that the double-sided strain gauge 12 includes two Wheatstone bridges 14 and 15 positioned around two spaced-apart substrates 13a to 13b within a flexible printed circuit board (FPCB) 15. The free space between the substrates 13a and 13b is illustrated and labeled by reference numeral 6, and it should be noted that no components or layers are contained within the space 6.

[0040] The Wheatstone bridge 14 includes resistors R1 to R4. In particular, resistors R2 and R3 are completely positioned on the top surface of the substrate 13a, and resistors R1 and R4 extend across the space 6 between the top surfaces of the substrates 13a and 13b. Similarly, the Wheatstone bridge 15 includes resistors R5 to R8. Here, resistors R5 and R8 are completely positioned on the bottom surface of the substrate 13a, and resistors R6 and R7 extend across the space 6 between the bottom surfaces of the substrates 13a and 13b.

[0041] The electrical connection of the Wheatstone bridges 14 and 15 is Figure 2B . Here, it can be seen that for the Wheatstone bridge 14, the resistors R1 and R2 are connected in series between the voltage Vs and the ground GND through the node p3, the resistors R3 and R4 are connected in series between the voltage Vs and the ground GND through the node n3, and the resistors R1 and R2 connected in series are connected in parallel with the resistors R3 and R4 connected in series. The nodes p3 and n3 are the outputs of the Wheatstone bridge 14. Similarly, for the Wheatstone bridge 15, the resistors R5 and R6 are connected in series between the voltage Vs and the ground GND through the node p4, the resistors R7 and R8 are connected in series between the voltage Vs and the ground GND through the node n4, and the resistors R5 and R6 connected in series are connected in parallel with the resistors R7 and R8 connected in series. The nodes p4 and n4 are the outputs of the Wheatstone bridge 15.

[0042] At normal operating temperature (between 0°C and 40°C), if Figure 2AAs shown, the FPCB 15 is deformed when a physical force is applied to the top of the double-sided strain gauge 12 in the downward direction, so that the strain on the resistors R1 to R4 changes relative to the strain on the resistors R5 to R8. In more detail, due to the fact that the resistors R1, R4, R6 and R7 extend across the space 6 between the substrates 13a and 13b, the change in the strain on the resistors R1 and R4 relative to the strain on the resistors R6 and R7 is greater than the change in the strain on the resistors R2 and R3 relative to the strain on the resistors R5 and R8.

[0043] The result is a change in the resistance of resistors R1 and R4 relative to the resistance of resistors R2 and R3, and a voltage differential is formed between nodes p3 and n3, so that the voltage Vp3-Vn3 is measurable. Similarly, depending on the location and magnitude of the physical force applied, there is also a change in the resistance of resistors R6 and R7 relative to the resistance of resistors R5 and R8, the formation of a voltage difference between nodes p4 and n4, and a measurable voltage Vp4-Vn4. Therefore, based on the voltages Vp3-Vn3 and Vp4-Vn4, at normal operating temperatures, the direction of the force applied to the double-sided strain gauge 12 and the magnitude of the force can be determined. In the case of a touch with negligible physical force, a minimum voltage differential is formed between nodes p3 and n3 and between nodes p4 and n4, so that the voltages Vp3-Vn3 and Vp4-Vn4 are negligible; therefore, at normal temperature, the double-sided strain gauge 12 is able to distinguish between a touch with physical force and a touch with negligible physical force.

[0044] In particular, the voltage ΔU can be determined, and thereby, by mathematically combining the voltage at nodes p3 and n3 with the voltage at nodes p4 and n4 to produce ΔU, the aforementioned direction of the force applied to the double-sided strain gauge 12 as well as the magnitude of that force can be determined.

[0045] Mathematically, ΔU can be calculated as follows:

[0046] ΔU1=Vs*[R2 / (R1+R2)]

[0047] ΔU2=Vs*[R4 / (R3+R4)]

[0048] ΔUout=ΔU1-ΔU2

[0049] ΔU3=Vs*[R6 / (R5+R6)]

[0050] ΔU4=Vs*[R8 / (R7+R8)]

[0051] ΔUin=ΔU3-ΔU4

[0052] ΔU=ΔUout+ΔUin

[0053] Note that extreme operating temperatures (less than 0°C or greater than 40°C) do not change the operation of the double-sided strain gauge 12 when subjected to a touch with pressure, because the application of force changes the resistance of resistors R1 to R4 relative to each other and to resistors R5 to R8.

[0054] Regarding touch without downward force applied, at extreme operating temperatures (less than 0°C or greater than 40°C), such as Figures 2C to 2D As shown, when the top of the double-sided strain gauge 12 is touched but no downward force is applied, the FPCB 15 is not deformed, which means that the touch does not cause a change in the resistance of the resistors of the Wheatstone bridge 14. In addition, the heat transfer from the user's finger (at about 36.5°C) to the Wheatstone bridge 14 is to all resistors of the resistors R1 to R4, so the resistance changes of the resistors R1 to R4 caused by heating the resistors R1 to R4 due to heat transfer are similar to each other. Therefore, the voltage difference between the nodes n3 and n4 of the Wheatstone bridge 14 is negligible, and therefore Vp3-Vn3 is negligible.

[0055] Furthermore, since the resistors R5 and R8 of the second Wheatstone bridge 15 are positioned on the bottom surface of the substrate 13a, and the resistors R6 and R7 extend between the bottom surfaces of the substrates 13a and 13b, the resistors R5 to R8 are not subject to the temperature difference between the user's finger and the ambient temperature of the double-sided strain gauge 12 itself. Therefore, even at extreme operating temperatures, in the absence of force, a touch to the double-sided strain gauge 12 does not cause a change in the resistance of the resistors R5 to R8, which means that the voltage Vp4-Vn4 is negligible. As a result of this, ΔU will be negligible (because Vp3-Vn3 is also negligible), and therefore a touch without force can be distinguished from a touch with force. Even in the case where a non-negligible voltage difference is formed between nodes n3 and p3 due to heat transfer, the influence of the non-negligible voltage difference between nodes n3 and p3 is reduced due to the mathematical combination of Vp3-Vn3 and Vp4-Vn4, so that ΔU will still be sufficiently negligible to be able to distinguish a touch with force from a touch without force.

[0056] The strain gauge 12 described herein may be incorporated into an electronic device 20 such as a smart phone, smart watch, wearable device, tablet computer, or laptop computer. Figure 3As shown. In practice, the strain gauge 12 may be incorporated into a touch screen or within a touch screen of the electronic device 20, or may be incorporated into a housing of the electronic device 20, for example to create a volume button, a power button, or a virtual assistant activation button on the side or back of the electronic device 20 without the need for conventional physical buttons. The electronic device 20 may include a strain gauge controller 21 for: reading the voltages at nodes Vp3, Vn3 and Vp4, Vn4; calculating ΔU as described above; determining the direction of the force applied to the strain gauge 12 and the magnitude of the force from ΔU, and reporting the determined direction and magnitude of the force to a microprocessor 23 within the electronic device 20.

[0057] Although the present disclosure has been described with respect to a limited number of embodiments, those skilled in the art having benefit of this disclosure will appreciate that other embodiments may be conceived without departing from the scope of the present disclosure as disclosed herein. Accordingly, the scope of the present disclosure will be limited solely by the appended claims.

Claims

1. An electronic device, comprising: Strain gauges, including: a substrate layer including a first substrate and a second substrate located in the same plane but spaced apart from each other; and a flexible printed circuit board, comprising a first Wheatstone bridge and a second Wheatstone bridge, the flexible printed circuit board being wrapped around ends of the substrate layer so that the flexible printed circuit board is in contact with both the top sides of the first substrate and the second substrate and the bottom sides of the first substrate and the second substrate; wherein the flexible printed circuit board positions the first Wheatstone bridge so that two resistors in the first Wheatstone bridge are positioned so that the two resistors span from the top side of the first substrate to the top side of the second substrate, and so that the remaining resistors in the first Wheatstone bridge are positioned only on the top side of the first substrate; and wherein the flexible printed circuit board positions the second Wheatstone bridge so that two resistors in the second Wheatstone bridge are positioned so that the two resistors span from the bottom side of the first substrate to the bottom side of the second substrate, and so that the remaining resistors in the second Wheatstone bridge are positioned only on the bottom side of the first substrate.

2. The electronic device according to claim 1, further comprising a strain gauge controller configured to: measuring a voltage difference between a first output and a second output of the first Wheatstone bridge; measuring a voltage difference between a first output and a second output of the second Wheatstone bridge; A voltage difference between the first Wheatstone bridge and the second Wheatstone bridge is determined as a difference between a voltage difference for the first Wheatstone bridge and a voltage difference for the second Wheatstone bridge.

3. The electronic device of claim 2, wherein the strain gauge controller is configured to determine a magnitude and direction of a force applied to the strain gauge based on the determined voltage differential between the resistors of the first Wheatstone bridge and the resistors of the second Wheatstone bridge. 4 . The electronic device of claim 1 , wherein the first Wheatstone bridge and the second Wheatstone bridge are coupled between a supply voltage and ground.

5. The electronic device of claim 1 , wherein the first Wheatstone bridge comprises: a first resistor positioned so as to span from a top side of the first substrate to a top side of the second substrate; a second resistor positioned so as to be positioned only on the top side of the first substrate; a third resistor positioned so as to span from the top side of the first substrate to the top side of the second substrate; as well as a fourth resistor positioned so as to be positioned only on the top side of the first substrate; wherein the first resistor and the second resistor are coupled in series between a supply voltage and ground, wherein a first output of the first Wheatstone bridge is electrically connected between the first resistor and the second resistor; and The third resistor and the fourth resistor are coupled in series between the power supply voltage and ground, wherein the second output of the first Wheatstone bridge is electrically connected between the third resistor and the fourth resistor.

6. The electronic device of claim 5, wherein the first resistor and the fourth resistor are physically positioned parallel to each other; and wherein the second resistor and the third resistor are physically positioned parallel to each other.

7. The electronic device of claim 1, wherein the second Wheatstone bridge comprises: a fifth resistor positioned so as to span from a bottom side of the first substrate to a bottom side of the second substrate; a sixth resistor positioned so as to be positioned only on a bottom side of the first substrate; a seventh resistor positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; as well as an eighth resistor positioned so as to be positioned only on the bottom side of the first substrate; wherein the fifth resistor and the sixth resistor are coupled in series between a supply voltage and ground, wherein the first output of the second Wheatstone bridge is electrically connected between the fifth resistor and the sixth resistor; as well as The seventh resistor and the eighth resistor are coupled in series between the power supply voltage and ground, wherein the second output of the second Wheatstone bridge is electrically connected between the seventh resistor and the eighth resistor. 8 . The electronic device of claim 7 , wherein the sixth resistor and the seventh resistor are physically positioned parallel to each other, and wherein the fifth resistor and the eighth resistor are physically positioned parallel to each other.

9. A strain gauge, comprising: a substrate layer, comprising a first substrate and a second substrate spaced apart from each other; as well as a first flexible printed circuit board portion in contact with top sides of the first substrate and the second substrate, the first flexible printed circuit board portion having a first Wheatstone bridge formed therein; wherein the first flexible printed circuit board portion positions the first Wheatstone bridge so that two resistors in the first Wheatstone bridge are positioned so that the two resistors span from a top side of the first substrate to a top side of the second substrate; as well as a second flexible printed circuit board portion in contact with bottom sides of the first substrate and the second substrate, the second flexible printed circuit board portion having a second Wheatstone bridge formed therein; The second flexible printed circuit board positions the second Wheatstone bridge so that two resistors in the second Wheatstone bridge are positioned so that the two resistors span from the bottom side of the first substrate to the bottom side of the second substrate.

10. The strain gauge of claim 9, wherein the first Wheatstone bridge and the second Wheatstone bridge are coupled between a supply voltage and ground.

11. The strain gauge of claim 9, wherein the first Wheatstone bridge comprises: a first resistor positioned so as to span from a top side of the first substrate to a top side of the second substrate; a second resistor positioned so as to be positioned only on the top side of the first substrate; a third resistor positioned so as to span from the top side of the first substrate to the top side of the second substrate; as well as a fourth resistor positioned so as to be positioned only on the top side of the first substrate; wherein the first resistor and the second resistor are coupled in series between a supply voltage and ground, wherein a first output of the first Wheatstone bridge is electrically connected between the first resistor and the second resistor; and The third resistor and the fourth resistor are coupled in series between the power supply voltage and ground, wherein the second output of the first Wheatstone bridge is electrically connected between the third resistor and the fourth resistor.

12. The strain gauge of claim 11, wherein the first resistor and the fourth resistor are physically positioned parallel to each other; and wherein the second resistor and the third resistor are physically positioned parallel to each other.

13. The strain gauge of claim 9, wherein the second Wheatstone bridge comprises: a fifth resistor positioned so as to span from a bottom side of the first substrate to a bottom side of the second substrate; a sixth resistor positioned so as to be positioned only on a bottom side of the first substrate; a seventh resistor positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; as well as an eighth resistor positioned so as to be positioned only on the bottom side of the first substrate; wherein the fifth resistor and the sixth resistor are coupled in series between a supply voltage and ground, wherein the first output of the second Wheatstone bridge is electrically connected between the fifth resistor and the sixth resistor; as well as The seventh resistor and the eighth resistor are coupled in series between the power supply voltage and ground, wherein the second output of the second Wheatstone bridge is electrically connected between the seventh resistor and the eighth resistor.

14. The strain gauge of claim 13, wherein the sixth resistor and the seventh resistor are physically positioned parallel to each other, and wherein the fifth resistor and the eighth resistor are physically positioned parallel to each other.

15. An electronic device, comprising: Strain gauges, including: a substrate layer, comprising a first substrate and a second substrate located in the same plane; a flexible printed circuit board including a first Wheatstone bridge and a second Wheatstone bridge, the flexible printed circuit board being in contact with both the top sides of the first substrate and the second substrate and the bottom sides of the first substrate and the second substrate; wherein the flexible printed circuit board positions the first Wheatstone bridge so that two resistors in the first Wheatstone bridge are positioned so that the two resistors span from the top side of the first substrate to the top side of the second substrate, and so that the remaining resistors in the first Wheatstone bridge are positioned only on the top side of the first substrate; wherein the flexible printed circuit board positions the second Wheatstone bridge so that two resistors in the second Wheatstone bridge are positioned so that the two resistors span from the bottom side of the first substrate to the bottom side of the second substrate, and so that the remaining resistors in the second Wheatstone bridge are positioned only on the bottom side of the first substrate; Strain gauge controller, configured as: measuring a voltage difference between a first output and a second output of the first Wheatstone bridge; measuring a voltage difference between a first output and a second output of the second Wheatstone bridge; and A voltage difference between the first Wheatstone bridge and the second Wheatstone bridge is determined as a difference between a voltage difference for the first Wheatstone bridge and a voltage difference for the second Wheatstone bridge.

16. The electronic device of claim 15, wherein the first Wheatstone bridge comprises: a first resistor positioned so as to span from a top side of the first substrate to a top side of the second substrate; a second resistor positioned so as to be positioned only on the top side of the first substrate; a third resistor positioned so as to span from the top side of the first substrate to the top side of the second substrate; as well as A fourth resistor is positioned so as to be positioned only on the top side of the first substrate.

17. The electronic device of claim 16, wherein the first resistor and the fourth resistor are physically positioned parallel to each other; and wherein the second resistor and the third resistor are physically positioned parallel to each other.

18. The electronic device of claim 15, wherein the second Wheatstone bridge comprises: a fifth resistor positioned so as to span from a bottom side of the first substrate to a bottom side of the second substrate; a sixth resistor positioned so as to be positioned only on a bottom side of the first substrate; a seventh resistor positioned so as to span from the bottom side of the first substrate to the bottom side of the second substrate; as well as An eighth resistor is positioned so as to be positioned only on the bottom side of the first substrate.

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