# FSR 402 force sensor: specs

> Round thick-film force sensing resistor whose resistance falls as pressure on its 14.68 mm active area increases.

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Round thick-film force sensing resistor whose resistance falls as pressure on its 14.68 mm active area increases.

Every value cites its sourcePinout not published

[Buy on Compoden](https://compoden.com/products/fsr-402-force-sensitive-resistor-compoden)

## Specs

| Spec | Value | Source |
|---|---|---|
| Actuation force | About 0.2 N minimum | source Device Characteristics (p.2) |
| Force sensitivity range | About 0.2 N to 20 N | source Device Characteristics (p.2) |
| Non-actuated resistance | More than 10 Mohm | source Device Characteristics (p.2) |
| Force repeatability, single part | +/-2 % | source Device Characteristics (p.2) |
| Active area (Model 402) | 14.68 mm diameter | source Model 402 Sensor Mechanical Data (p.6) |
| Nominal thickness (Model 402) | 0.46 mm | source Model 402 Sensor Mechanical Data (p.6) |
| Operating temperature test points | -40 C cold and +85 C hot tested | source Device Characteristics (p.2) |
| Rise time | Under 3 microseconds | source Device Characteristics (p.2) |

## Power

| | Value | Source |
|---|---|---|
| Supply | Resistive sensor, no supply pin; the sheet's divider example uses V+ of 5 V | source Application Information (p.3) |

## Pinout
We don't publish a pin table for this part: no official source we could verify gives one. Check the labels printed on your module, and see the notes below.

Two-wire sensor; the sheet lists connector options (bare tail, female contacts, solder tabs) and no pin names. The listing's connector type is not stated.

## Build with it
Project ideas for the FSR 402 force sensor. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.

- [Press-strength meter](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20press-strength%20meter%20that%20shows%20an%20FSR%20402%20reading%20as%20a%20bar%20on%20an%20OLED%2C%20using%20an%20Arduino%20Uno-compatible%20board%20and%20a%20fixed%20resistor): A divider with a fixed resistor feeds one analog input, as in the sheet's example circuit.
- [Drum pad trigger](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20drum%20pad%20that%20sounds%20a%20buzzer%20when%20an%20FSR%20402%20is%20tapped%2C%20using%20an%20Arduino%20Uno-compatible%20board%20and%20a%20fixed%20resistor): The sensor rise time is under 3 microseconds, so a code threshold catches quick taps.
- [Pressure-controlled LED brightness](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20lamp%20whose%20LED%20brightness%20follows%20how%20hard%20an%20FSR%20402%20is%20pressed%2C%20using%20an%20ESP32%20board%20and%20a%20fixed%20resistor): Run the divider from 3.3 V so the analog input stays within the board's range.
- [Foot-press counter](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20foot-press%20counter%20that%20counts%20presses%20on%20an%20FSR%20402%20and%20shows%20the%20total%20on%20a%2016x2%20LCD%2C%20using%20an%20Arduino%20Uno-compatible%20board): Learning project; the sheet reports a tap durability test of 10 million actuations.

## Common mistakes

- Reading it without a measuring resistor: wire it in a divider, VOUT = RM x V+ / (RM + RFSR), with RM chosen for the force range (source: [link](https://cdn-shop.adafruit.com/datasheets/FSR400Series_PD.pdf), Application Information).
- Swapping the divider order and expecting the same trend: with RM and RFSR swapped the output falls as force rises (source: [link](https://cdn-shop.adafruit.com/datasheets/FSR400Series_PD.pdf), Application Information).
- Treating it as a precise scale: the graph values are reference only and depend on the actuation mechanics (source: [link](https://cdn-shop.adafruit.com/datasheets/FSR400Series_PD.pdf), Application Information).

## Not covered by the official source

- Model confirmed as FSR 402 (14.68 mm active area) from the 400-series sheet.

## Sources

- [link](https://cdn-shop.adafruit.com/datasheets/FSR400Series_PD.pdf) (Interlink Electronics FSR 400 Series data sheet, P/N 94-00027 Rev. D)