I prototyped a simple arduino device to take care of doing the counting of the repetitions and durations because watching a stopwatch wasn't quite working for me. The RepWrap uses LED flashes and vibrations to let me know when to finish a stretch or change legs or whatever. The LEDs give me a 3 second countdown at the end of each hold, then the vibe gives me some changeover/rest time. The combination of sight, touch and sound mean that I can do my exercises whilst listening to music or with my eyes closed (useful when trying to squeeze in an early morning set before going to work!).
In this instructable I'll show you the simple breadboard layout and code to use to make your own RepWrap.
You will need:
- Arduino-compatible microcontroller (I'm using a RBBB from Modern Device)
- A breadboard (Only if your microcontroller requires it. If you're using a regular Arduino board, you won't need it. I'm using a Maplin AD100)
- An LED (You should probably use a 330ohm or similar resistor in series with it too...) Your microcontroller may already have an integral LED attached to pin 13, but I found this wasn't visible enough for my needs.
- A pager motor (I'm using one of these pager motors)
- 9V PP3 Battery (it's easier to put a little more boogie into your exercises if you're not leashed to a computer by a USB cable...)
- Battery clip and 2.1mm plug power jack (wired up to be centre-positive)
- 2 lengths of wire to extend the motor leads (I'm using single core so I can plug it into the breadboard)
- 2 x Jumper leads long enough to reach between the GND pin on your controller and the selection pins for number of reps and length of duration.
- Rubber band
- Masking tape
- Insulation tape
- Soldering iron, solder and stand etc
- Something to strip the ends of insulation off the wire
And if you're wondering about the name:
The plan is to eventually build this circuit into a sleeve worn around the forearm. There'll probably be a few more instructables en route...
In the meantime I'm using this version to try and get a feel for what needs to go into the final design.