How to Make Super Cheap Flex Sensor


Introduction: How to Make Super Cheap Flex Sensor

If you ever wanted to make an animatronic hand that is controlled by your own hand and thought that paying around $10 for just one flex sensor is a bit too much, then this instructable is for you.

Parts needed:

  • a piece of IV tube
  • electrician's tape
  • red LED
  • photoresistor
  • 1 kOhm resistor
  • 10 kOhm resistor
  • modelling balloon

Step 1: Grab Your IV Tube

Step 2: Insert the LED Into the Tube

Step 3: Sercure the LED With Electrician's Tape

Step 4: Do the Same With the Photoresistor

Step 5: Wrap It in Tape and Put the Cut Ballon Over It

The light will be travelling through the tube and the more bent it is the less light will be getting onto the photoresistor thus increasing its resistance.

Now you will need to connect it like you normally connect a LED and a photoresistor but use the 1 kOhm resistor for LED to make it less bright as the light should not escape the insulation for best results.

Note: if you are going to use more then one of them, use the same color of LED because photoresistor reacts differently for different wavelenghts.



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    If you fill with a photo clear liquid it won't kink .

    Just curious what the response is like--is it anywhere near linear? Even if it isn't linear, as long as it's fairly consistent you could program a mapping function I guess.

    It's really interesting. Can you show some measurements with your flex sensor