I decided to expand on the paperduino instructable, as some areas were missing and some stages incomplete. This is the original instructions https://www.instructables.com/id/Paperduino-20-with-Circuit-Scribe/
The instructable makes the whole process look incredibly easy. ”Within 15 minutes we printed the board, placed components down with glue or tape, and uploaded a sketch“. However a number of issues arose in the process.
Firstly with the PCB I had issues (I was using a Cricut) so because of the way the layout is and the un-editable interface of the CricutDesigner, it was difficult to get the correct scale for the drawing. I had to take a measurement from a length of the CAD drawing and then translate this into the cricut design.
I also found that the circles were a bit useless as the pen would get clogged while drawing these, so I had to edit them out, and then draw them in by hand later on. It was the same with the pads as well - if you look at the sketch above you can see where this has been done - some of the lines are not so even.
If you plan to use magnets for the connections, make sure to extend some of the pads away from the board. - such as the GND and VCC, as the magnets used to make the connections will repel or attract each other when too close.
Paper wise- as instructed, anything smooth and unabsorbant works best. I tried a Japanese paper but it got very fluffy in the drawing process, so coated papers are a must.
Something which I learnt later and have discussed in the post, 'Expanding the Max7219', is that the conductivity of the circuit scribe can be greatly improved by heat, I ran my circuits through a laminator - without the lamination pouches to do this. Attaching the components did not cause too many problems - until it came to bootloading the chip -
Bootloading was pretty tricky. I was using the Programmer USB AVR Pololu v2.1 – microUSB 3,3V/5V. Which perhaps wasn't the easiest approach. I found Atmel Studio best for programming as it gave details of what was really going on.
However, I tried a few times and again found issues with connections, whether I used z-axis tape (a tape which allows conductivity to connections below) or not, I found it would come loose pretty easily. I painted on the connections with a high-quality silver ink also, but although I managed to program it, it was unreliable. In later experiments I discuvered that having a very stable surface helped a great deal, as did conductive epoxy - or even soldering the components to the paper.
Comments