Hi Matt,
the trigger board is bought (~10 USD if I remember right) and I use this one:
Just check Google/Amazon for ZY12PDN, I'm sure you will find something. But please remember, you will need a Powerbank that supports the Power Delivery (PD) protocol and the output voltage/power you need. PD options are 5V-9V-12V-15V-20V, 3-5 Amps, but not all powerbanks can do this.
Another word of warning: Not all powerbanks provide a "clean" output. I have one powerbank with no issues at all, but another one introduces pretty noticable noise. To work around the isssue, I added some capacitors and a choke at the output of the trigger board (FYI: the choke had actually no effect, the capacitors did the job). In the end, it looks like this:
Hope this helps,
Matt
