With the HDD Synth MKV off with JLCPCB for a limited prototype run I had the time and headspace to work on another little hardware project that's been on my mind

I bought a walking treadmill along with a standing desk a few years ago so that whilst working from home I'm able to get more exercise during the day. Spending too much of the day sitting at a desk just isn't good for you, plus I suffer from a bad back which it certainly doesn't help with either.

I invested in the JTX MoveLight after some research which is a well regarded no frills treadmill, perfect! I can set it running and then it'll go for 90 minutes at whatever speed I'd like which gives me a good leg stretch.

The problem is that this duration at a single speed isn't great for your back, it can over stress some of the muscle groups leading to others having to compensate which causes back pain. A better approach is splitting this into two separate 45 minute sessions and varying the speed throughout. 

Great - except that means having to constantly watch the clock and make manual changes. If only my dumb treadmill was smart enough to do this itself...

I'm getting very familiar with the Pi Pico, so I decided to pair one with a display from Pimoroni and a 433MHz STX882 transmitter

This provides me with a visual representation of my treadmill program along with the means to communicate the start, stop and speed change commands to the treadmill.

When the Treadmill Buddy is turned on it'll generate a treadmill program of 45 minutes with speed changes of +/- 0.5KPH every 5 minutes. It shows this as a bar chart before the program runs. By pressing a button you can generate a new program, if for some reason you're not quite happy with the current one.

When you're ready pressing another button will start the program.

It uses an STX882 transmitter to send RF commands to the treadmill, just the same as the official remote. So whenever the Treadmill Buddy determines it's time to change speed, it'll send the command via the RF module.

In order to capture the commands from the treadmill remote that I wanted to duplicate I used a SRX882 receiver, which thankfully came with the set I purchased on eBay.

Thankfully the wiring on these devices is pretty straightforward, with essentially just a power, ground and then data line. So it's easy for the Pi to capture RF transmissions and then send these on demand.

After wasting a bit of time getting the RF transmitter and receiver modules confused (yeah, they don't work the other way round!) I was able to quite quickly cobble together a proof of concept

But how did I know that I could use a 433MHz RF module to capture the treadmill remote's output? Well... my first attempt at this was cracking open the remote and attempting to drive the button presses directly

This worked... but added more complexity through the addition of a CD4066 chip along with a lot of extra wires!

It was whilst doing this and looking at the chips inside that I determined the remote was most likely using the 433MHz frequency from the clock crystal being used. Thankfully this proved to be correct and I was happy that my £10 eBay RF transmitter and receiver were able to provide a much cleaner solution

If you'd like to build one yourself, I've made the entire project Open Source at https://github.com/MaverickUK/TreadmillBuddy

Happy walking!