Make Controller + 4x4 button PCBs?

Archive New Product Ideas
1

Hello,

I am working on a music research project, and I was hoping to get a few monomes (http://www.monome.org), but the chances of that happening in the next year are slim…

So I am now planning on going the do-it-yourself route. I plan to make a bit of a sensor heaven box, included IR and such… but I would like to include the LED/button functionality of the monome, preferably in an 8x4 grid.

In order to accomplish this, I am planning on using the Make Controller Kit (http://www.makingthings.com), but my relatively small knowledge of schematic charts prevents me from completely understanding the plausibility of this in combination with 2 4x4 PCBs from sparkfun:

Button Pad 4x4 - Breakout PCB (SKU#: COM-08033)

and of course LEDs.

Would this be a possible (preferably USB-powered only) route?

Any and all help is greatly appreciated; if the Make Controller idea sucks, any pointing in a different direction rocks too.

  • Alex
2

It seems like that’d work. I haven’t used the Make controller but it seems like a pretty good product. The Application board has [some reasonably high-current drivers on it which is very handy but it only has eight of them, so you’ll probably have to [wire up some transistors to other outputs on the controller board in order to drive all the button pad rows/columns.

The other obvious choice for a controller board is an Arduino, which is significantly cheaper, and correspondingly less capable, but should still be easily up to the task of being a lights-and-buttons-and-stuff peripheral to a PC.

You’ll have to calculate the current draw to see if it can be USB bus-powered — matrices full of brightly lit LEDs can consume a lot of power and USB devices are only allowed to draw, I think, 500mA from the bus.](http://www.opencircuits.com/Basic_Circuits_and_Circuit_Building_Blocks#Transistor_Low_Side_Switch)](http://www.makingthings.com/documentation/faq/how-much-current-can-i-run-through-the-outputs)

3

I think the make controller is probably way overpowered for what you want to do. (Though, it’s not clear exactly how far you want to take it.) The biggest issue is I/O. There are lots of ways to drive that many LEDs and buttons. There have been a number of threads in the SFE forums on that topic - you should take a look. I would look at using a USB PIC as the basis.

You could probably power a 64 LED unit via USB but not the larger ones. Note that the monomes larger than 64 are external powered.

Phil

4

I want to also add two potentiometers (two slide, two knob) and an IR distance sensor for theremin-like application.

So would the 8x4 grid w/LEDs and these 5 other input devices be manageable with the MC kit?

How can I find some more detailed instruction on how to wire up the keypads? That’s the elusive part. I understand the diode situation, but the actual data doesn’t quite make sense to me in terms of how to wire them. That’s the reason for this post really.

Also, if you could link me to particular forum posts/tutorials referencing this issue, that would rock.