Intro: DIY Microcontroller - Hand Dynamometer
7) Double sided tape
Tools require :
1) Hot glue gun
3) Soldering iron
4) Metal files
6) Pen knife
Step 1: Get the Right Size Flex Sensor.
- Bought the Flex Sensor 2.2" from Amazon, which can fit nicely around the circumference of the metal spring on the Hand Exerciser.
Step 2: Solder the Terminals
- Solder the wire to the Flex Sensor 2.2" using the plier to hold the sensor down.
- While soldering please be careful not to soldered directly on the mica sheet.
Step 3: Making the Backing Material for the Flex Sensor Terminals
- The Flex Sensor 2.2" is fragile at the terminal part. So to strengthen it, I cut out some plastic piece from a plastic IC shipping tube.
- You will then glue the flex sensor on to the plastic piece just little over the label on the flex sensor. The flex sensor label should face down as shown on the picture.
Step 4: Hot Glued the Terminals and Trim the Excess Plastic.
- Hot glued the terminals to insulate it as well as to provide extra protection.
- Use a pen knife to level the hot glue before it solidified.
- Trim off the excess plastic with a scissor.
Step 5: File the Metal Ring and Secure the Flex Sensor
- Position the Flex Sensor 2.2" flex sensor along the circumference and mark the metal spring using a maker.
- Marked 3 points left, centre and right.
- Then use a metal file to file a groove which the cable ties can just fit.
- Stick a double sided tape along the metal ring.
- Stick the flex sensor along the double sided tape.
- Then secure the flex sensor with cable ties.
Step 6: Testing the Hand Dynamometer Using a Multimeter.
- Connect the sensor cable to a multimeter and switch to resistance setting. You should get a reading between 56 kOhm and 80 kOhm when you release or depress the Hand Exerciser.
Step 7: Interface the Sensor to PICAXE 28x2 Microprocessor
- Make the interface board for the flex sensor. And the PICAXE program can be downloaded :