HOW TO: Build a logic board for $30

  • I wanted to share the logic board I built for my monome using the unsped shield and the iDuino (an Arduino clone).

    The iDuino is the cheapest Arduino compatible board I could find that has a full-sized USB-B connector. I omitted the headers and soldered wires directly to the board (see attached picture).

    Total cost:
    Unsped shield $7.68 from group buy
    iDuino kit $17.82 + $3.02 shipping from spiffie.org
    74hc164 and 74hc165 $0 (free samples) from Fairchild Semiconductor
    MAX7221CNG $0 (free sample) from Maxim
    Resistor network, socket, filtering caps

    734 x 700 - 1M
  • > It's hard to label the monome project as "elitist" or "exclusive" when you can build a 40h for under $150 on a budget and use it with all this great free open-source software.

    shit, just look at edison's

    > lunchbox

    sparkfun buttons pull their weight, but i think they're too big for practical use. an 8x8 sparkfun board is nearly as big as my 256.

    i think your

  • You're probably right about the Digi-Key shipping -- I got my components as part of a larger order which cost $2.50 to ship USPS. Maybe "How to build a logic board for $32" would be a more accurate title.

    The 3.3v is a standard Arduino pin. On the site it says the iDuino doesn't break out the 3.3v pin but I verified it on the multimeter and it turned out to work just fine. Saved me from having to add a voltage converter for the accelerometer chip. So you get two nice features not present on the official logic board (3.3v out and easy reprogramming over USB).

    I was thinking about drilling mounting holes but the bottom of my case is too thin for blind holes and I didn't want any exposed screws. I ended up using this sticky wax stuff intended for mounting posters. When I'm sure I don't want to change anything on the circuit board (e.g. I_set resistor value) I may glue it in place.

    Sparkfun button pads -- yes they are huge! I bought an official button pad kit from monome with no regrets. It's well worth the extra cost just for having everything on one PCB. I'm still envisioning a DIY button solution since they are the most expensive part and the hardest to obtain.

  • nice wireup! looks very clean. i'd like to see more clones built from non-monome non-sparkfun lit keys. they always have a lot of character.

  • where was the PCB from? just one big one insteada 4x wired together?
    just wondered....
    is it an official monone oboard?