E-Stim Device V1.0: From Breadboard to Custom PCB
I'm designing and building my own e-stim (electrical stimulation) device. Version 1.0 is built around an ESP32 microcontroller, and it has just reached a milestone: a custom circuit board that I designed and had made professionally.
Why build one?
This one has been a long time coming. I've spent many years working as an electrician and with electronics, and I've had a long-running interest in e-stim and violet wands. Put those together, and it was time to build one of my own.
Knowing how electricity behaves, and how to work with it safely, is what makes a project like this realistic rather than reckless. It's also why I'm taking it one careful step at a time.
Here's how it got there so far.
Step 1: the breadboard
Every electronics project starts with a breadboard. It's where you find out whether the circuit works before committing it to anything permanent. The first working version of the device was built this way around an ESP32: a tangle of jumper wires, but a working circuit.
Step 2: a home-made PCB
Breadboards are great for trying things out and terrible for anything you want to rely on. Wires work loose, connections get flaky and it's hard to build the same thing twice.
So the circuit moved onto a PCB I made myself. It was a big step up in reliability, and it showed how the circuit would behave once everything was fixed in place.
Step 3: a custom board from PCBWay
The latest version is a custom board I designed in KiCad and had made by PCBWay. A professionally made board gives you proper copper traces, a solder mask and consistent results. It also means I can make more than one identical board.
Designing in KiCad also gives me a proper record of the circuit, which makes the next version much easier to start.
What's next
- Testing: testing the V1.0 board starts soon. This is where I find out how the custom board compares with the earlier versions.
- Move to STM32: a later version will move from the ESP32 to an STM32 microcontroller.
More about e-stim
If you want background on e-stim itself, including how-to guides, notes on units and electrodes, and safety guidance, see my dedicated site, e-stim.kreativekommit.com. Its sister site, violet-wand.kreativekommit.com, does the same for violet wands.
The E-Stim Device project page on the Workshop site is updated as each stage is done. I'll post the testing results here once I have them.