The goal with Polyformer-Lite is to use the least expensive most easy to source components. In the original machine, we use a generic Klipper microcontroller. 

While it is easy to find such a board on Amazon, it is less easy to source in Rwanda.

Shipping such a part through Aliexpress is over $200.

The klipper board is overkill for our project anyways, all we need is something that can turn our heater cartridge on/off.

Credit goes to Ondřej Šraitr from the petamentor project for identifying how the W1209 board can be used for this task. This board is just a simple relay that can turn over heater on/off, no PID though :(

[Figure: W1209 sold by Rwandan electronics store]

The board is fairly popular and sold directly by a Rwandan electronics store for $5USD - no shipping needed!

If users do are not able to make a W1209 board, maybe they can also make one from scratch? The parts on the board seem pretty standard, maybe I'll try building one when I am in Rwanda.