Flex Sensor 4.5''
Last updated: 5 October 2012
Prepared by Vanissa Law [vanissalaw@gmail.com]
URL: https://www.sparkfun.com/products/8606
Cost per unit: $12.95 USD (approx. 100 HKD)

General Information
About Flex Sensor
The flex sensor changes resistance when bent. An un-flexed sensor has a nominal resistance of 10,000 ohms. As the flex sensor is bent in either direction the resistance gradually increase to 6000 ohms to 110, 000 ohms.

Features & Specifications
For full specs refer to datasheet available here:
Here’s a list of important features to note:
- Temperature Range: -35°C to +80°C
- Resistance Tolerance: ± 30%
- Power Rating: 0.50 Watts continuous. 1 Watt Peak

Some things to know when working with flex sensors

- Be aware that any irregular bending may produce irregular results. For example, the bend on the left will usually give unreliable results since it is bent backwards first, then forward.

- Most flex sensors seem to take some time to revert back to low numbers at rest. In order words, the original at rest/ no bend reading may be 65, but after bending, the low number at no bend will be 80 for at least 20 seconds.

Getting it to work!

Connections shown are as in the basic flex sensor circuit example code below.
flex (2).jpg

Routing readings into Max
1. Open Arduino software. From the "File" pulldown menu choose Examples> Firmata> AllInputsFirmata. Then upload the code onto your Arduino.
2. Open the "MaxuinoForLUME" patch. Click the "print" message box on the grey panel. It will print all the available serial prots on our computer into the "umenu" underneath. Choose "usbmodem621" port to route serial data form Arduino into Max.
3. You should ses readings routing thru max and a MIDI note will be played when the sensor is flexed.