DIY : tsnm (Touch Sensing Note Memory) by Doboz


Good to know, thanks. I really liked the chipquik, easy to use and pretty fast. :+1:


IC1 upper side in the middle: could be a solder bridge between the legs.


Thanks for checking! That is just a glistening spot from I guess the flux, but i’ll DEFINITELY double check it. Haha :sweat_smile:


Here is another one, its the smallest of the mutli-pin chips. It definitely looks to me like there is a connection between the pads (circled in yellow) — but i believe this is not solder but actually right on the pcb (scratch?)

Any thoughts? I am not sure what to think…


An Xacto knife, carefully wielded, usually cleans up pcb shorts. Be sure it’s not in the schematic, first, though!


Just checked my pcb. They are supposed to be connected


Oh man, i was trying to scrape them apart too. Thanks guys.
Its going to be a miracle if this work in the end. :slight_smile:


It looks like the holes on the board don’t line up exactly to the ones pcb here, not sure if i got the wrong board or if I should split the difference on the position and bend the pins a bit:


uuuh no…I ordered an adafruit board too…argh…thought it would be better than a cheaper one…possible that the cheaper ones fit…:see_no_evil:


these should fit! they look bit bigger than the adafruit boards…


That definitely looks more like the one in the beauty shot on the site:

He does mention that the blue boards should be better than the black.


ahh ok. I found one on amazon that looks right.

I’m down to the socket pins now – and trying to figure that out. I guess i’ll do the Teensy and mrp121 to the PCB first, then the ones under the mrp121 to the panel last.

edit: Actually – I wonder when is the best time to test and see if it works? – I should probably plug it in before the PCB sockets are soldered to the front panel. Anything I should be looking for at that point?


checking for shorts is always a good idea. especially between V+,V- and GND


just about to solder C14 with this substitute part and realized it is 50v rather than 16. is this okay or should I track down a 16v?


Totally fine! Higher values are no prob!! It means the cap can handle up to 50V


I can’t believe i finished this and it actually works!! :sweat_smile:

Thanks so much for all the help everyone, I definitely would not have completed it without the lines group effort :slight_smile: — big virtual high fives!

@reijo your help at the end was critical, thanks for taking the time, much appreciated.

Even the cat likes it!


awesome, good work!!


Cool thank you! It’s disconcerting when you are about to solder something that tiny with less than 100 percent certainty its the correct part :slight_smile:


Had some time today to test it out – i’ll put that in the video thread. Thanks again all, its working as expected!


has anyone found a source for the MPR121 capacitive touch board in the USA? i found one, but they are charging $14 per board!