Muxes, servos, and two MCU's

The plan is to:

  1. collect about 80 analog inputs with 5 MC14067B’s
  2. Funnel them into this: http://www.digilentinc.com/Products/Detail.cfm?Prod=CHIPKIT-MAX32
  3. Send this data wirelessly using an XBPro S2 to another MCU
  4. The receiving MCU will convert the analog data to PWM and send it to 80 servos, updating every 20ms (if necessary?)

I have the slide pots, one of the MCU’s, the XBPro’s and the servos but i’m not quite sure if the wireless connection handle 80 channels at that rate? it is rated for 250kbps so it would seem so.

I haven’t looked into using two arduino’s this way but i’m sure it can be done.

Any input on this would be appreciated. thanks. this is really my first serious arduino project. I have been able to wirelessly control ten servos using a USB joystick but I was able to just steal all the code for that.

Unfortunately the ChipKit-Max32 is not an Arduino although it looks like one. It's not based on the AVR microcontrollers as are the Arduinos but on a PIC32 which is a completely different architecture. Some shields may be (hardware-wise) compatible but software is quite a different beast. Hence you might get better answers on a PIC forum or better on one specific for the ChipKit platform.

Can you expand a bit on "software"? do you just mean the sketches? because I have copy and pasted several sketches and they work exactly as they should.

This is true as long as you don't use hardware features in the software. If you just use digitalWrite and digitalRead you're fine. You may even get some SPI code running but, to give you an example, if you use a hardware timer, the resulting code would not work on the chipKit. It's not an Arduino although it looks a bit like one. You wanna use PWM in your project and I guess the PIC32 is quite different how it handles PWM so you probably won't get much help in this forum. That's why I suggested a PIC forum, there you have experts for your platform.

Ok, i'm pretty new to arduino so i'm just tackling problems as they come and I havent run into that yet. I'm sure that's just because i'm running pretty basic stuff. Thanks for the info. I've tried the chipkit forum for a few things but they are slow to respond since they have a much smaller membership.

That’s because chipKit is by far not used as often as the Arduino platform. There’s probably also less experience around for the platform because it tried to marry two platforms (the PIC at the processor side, the Arduino at the connector side), so both communities have a part which they are not familiar with.

As chipKit is designed and produced by a company you might get support there.

Usually people start with the Arduino platform, experiment with the possibilities, get experience with connecting hardware and writing the software for it and when they hit the performance limit they change to Leaf Maple or sometimes the chipKit.

I’d start your problem with an Arduino and let’s say 3 inputs and servos and see how that fits. You might find limits in the data rate of the XBees before you reach the 80 channels you wanna have in the end (if data exchange is optimised: 4 Bytes * 80 channels * 50 updates per second = 160kBit/s minimum, which is pretty demanding for the XBee).