Costum-made pressure sensor, FSR, strain gauge

Hello,

does anybody know any companies, located in Europe, that are manufacturing costum pressure sensor, FSR, strain gauge? I'm looking for thin "FSR shape-style" sensor for measuring heavier weights. I know FSR sensors have bad accuracy but load cells are just too big for my project and they measure only on one spot. It has to be thin sensor.

Ask the internet for "strain gauge producer europe"

Hello,

I found Flexiforce a502 sensor that can measure weights up to 44,482 N

"The A502 sensor is available in a 0-222 N (0-50 lb) range, specified with Tekscan electronics.
This model is linear through a much lower range of 0-22 N (0-5 lb), and is capable of
measuring loads up to 44,482 N (10,000 lb)." - from the datasheet

"In order to measure higher forces, apply a lower drive voltage (-0.5 V, -0.25 V, etc.)and reduce the resistance of the feedback resistor (1kΩ min.). To measure lower forces, apply a higher drive voltage and increase the resistance of the feedback resistor."- from the datasheet

My question is can the sensor be powered with normal +5V that Arduino provides and what is the maximum load the sensor puts out by powering it with +5V? I want to avoid powering it with negative voltage. I also read #4 post on this thread saying applying a negative voltage to any of the Arduino pins would damage the chip.

https://forum.arduino.cc/index.php?topic=368539.0

tomi12345:
My question is can the sensor be powered with normal +5V

Yes, you could use a simple voltage divider with 5v, but it is not Tekscan's "best practice." They recommend 2 to 3.3 v DC.

You really should read https://www.tekscan.com/sites/default/files/BP%20-%20Electrical_Integration_FINAL_081817_0.pdf to see Tekscan's recommended inverting, non-inverting, and voltage divider circuits.

And why not use Tekscan's preferred circuit, the inverting op-amp? Don't worry - it outputs a positive voltage.

To generate the negative reference that it needs, you could try using the Arduino and the circuit shown in post #3 here. Test it to see if it is suitable for your needs.

DaveEvans:
You really should read https://www.tekscan.com/sites/default/files/BP%20-%20Electrical_Integration_FINAL_081817_0.pdf to see Tekscan's recommended inverting, non-inverting, and voltage divider circuits.

I like the non inverting op amp circuit (single source).
If I understand this correctly I should power up op amp with 0.25-1.25V. I plan using Mini-360 DC-DC Buck converter and dial the 5V arduino pin voltage down to 1V and hook Vout to arduino analog pin? Is Vsupply = Vref?
And what resistance are R1 and R2?

tomi12345:
If I understand this correctly I should power up op amp with 0.25-1.25V.
Is Vsupply = Vref?

No and no. Have another look at the document, including the notes on the graphs for the non-inverting example.

tomi12345:
And what resistance are R1 and R2?

They form a voltage divider. Do you know what that is? Choose R1 and R2 as needed for Vref to be the desired value (may need some trial and error), within in the recommended range, and not draw too much current.

Aha got it now. There is no need for Mini-360 DC-DC Buck converter, the voltage divider is already in the circuit and Rfeedback= 100kΩ potentiometer is used to adjust the sensitivity of the sensor. I just have to calculate which R1 and R2 to use to get out Vref=0.5V from a 3.3V Arduino pin and watch out for the current on the sensor so it doesn't exceed maximum rating.
Thanks for showing me the Tekscan's documentation.