# Spectra flex sensor 2.2 inch: specs

> Two-terminal flex sensor whose resistance rises as it is bent; used for angle displacement measurement such as finger bend in a glove.

[HTML version](https://soldr.ai/docs/components/flex-sensor-2-2-inch)

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Two-terminal flex sensor whose resistance rises as it is bent; used for angle displacement measurement such as finger bend in a glove.

Every value cites its sourcePinout not published

[Buy on Compoden](https://compoden.com/products/spectra-flex-sensor-22-inch-bend-sensor-for-hand-recognition)

## Specs

| Spec | Value | Source |
|---|---|---|
| Flat resistance | 25 kohm, tolerance +/-30 % | source Electrical Specifications (p.1) |
| Bend resistance range | 45 kohm to 125 kohm, depending on bend radius | source Electrical Specifications (p.1) |
| Power rating | 0.50 W continuous, 1 W peak | source Electrical Specifications (p.1) |
| Temperature range | -35 C to +80 C | source Mechanical Specifications (p.1) |
| Life cycle | More than 1 million | source Mechanical Specifications (p.1) |
| Active length | 55.37 mm (2.180 in) | source Dimensional diagram (p.1) |
| Part length | 73.66 mm (2.900 in) | source Dimensional diagram (p.1) |
| Height | 0.43 mm (0.017 in) | source Mechanical Specifications (p.1) |

## Power

| | Value | Source |
|---|---|---|
| Supply | Resistive sensor, no supply pin | source p.1 (power rating only) |

## 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-terminal passive sensor (solder tab connectors), no pin names in the sheet. The mirror-hosted PDF is a verbatim Spectra Symbol sheet (Rev A2).

## Build with it
Project ideas for the Spectra flex sensor 2.2 inch. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.

- [Flex-controlled servo glove](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20glove%20that%20moves%20a%20small%20servo%20when%20a%20finger%20bends%2C%20using%20an%20Arduino%20Uno-compatible%20board%2C%20a%20flex%20sensor%20and%20a%20servo): A divider with a fixed resistor near the 25 kohm flat value feeds an analog input; the servo uses its own supply.
- [Bend angle display](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20bend%20angle%20display%20that%20shows%20a%20flex%20sensor%20reading%20on%20an%20OLED%2C%20using%20an%20ESP32%20board%20and%20a%20fixed%20resistor%20divider): Run the divider from 3.3 V so the analog input never sees more than the board allows.
- [Posture reminder strap](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20posture%20reminder%20that%20buzzes%20when%20a%20flex%20sensor%20on%20a%20strap%20bends%20past%20a%20limit%2C%20using%20an%20Arduino%20Uno-compatible%20board%20and%20a%20buzzer): Learning project: a threshold in code compares the divider reading; the sensor is rated for over 1 million cycles.
- [Bend-controlled LED brightness](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20lamp%20whose%20LED%20brightness%20follows%20how%20far%20a%20flex%20sensor%20is%20bent%2C%20using%20an%20Arduino%20Uno-compatible%20board): Map the divider reading to PWM output on the LED through a series resistor.

## Common mistakes

- Reading it without a divider: it is a resistor, so wire it as a voltage divider and read the middle point; the sheet suggests a low-bias-current op amp buffer such as LM358 or LM324 (source: [link](https://www.sparkfun.com/datasheets/Sensors/Flex/flex22.pdf), p.2 Schematics).
- Expecting identical values on every unit: flat resistance has a +/-30 % tolerance, so calibrate each sensor (source: [link](https://www.sparkfun.com/datasheets/Sensors/Flex/flex22.pdf), p.1).
- Exceeding the power rating: it is rated 0.50 W continuous and 1 W peak (source: [link](https://www.sparkfun.com/datasheets/Sensors/Flex/flex22.pdf), p.1).

## Not covered by the official source

- Listing says 2.2 inch; the sheet's 55.37 mm active length equals 2.18 inch, matched to this part.

## Sources

- [link](https://www.sparkfun.com/datasheets/Sensors/Flex/flex22.pdf) (Spectra Symbol Flex Sensor data sheet, Rev A2)