Hi everyone! I'm hoping that the forum might be able to provide me with some guidance. I'd like to build a hexapod walker robot, and am in the initial planning stages. I have a background in CS, and am starting to get into electronics, and robotics, as a hobby.
I have an Arduino Uno that I'd like to use as my micro controller, and would like to support a stupid number of servos, and sensors.
I'm thinking that I'll want to use a "large" RC battery to power everything. I'd like to get away from using AAs! To those ends, I'm thinking that a 12v RC battery will suit my purposes, and I'll use one of these to regulate the voltage to something consistent. I'm thinking I'll want a steady 12v off my battery, and then run that through some linear voltage regulators in parallel to give myself a 12v, 9v, 5v, and 3.3v line. One thing that worries me is the fact that those regulators are advertised as being non-isolating. Is that something I should worry about?
As far as the servo control is concerned, I'm thinking that a few of these I2C servo boards will work nicely. I'm thinking that those will allow me to run my servo's off of 12v (or however much they need), while running my Arduino off of 5v. Those little boards should allow me to control quite a number of servos. Each of those boards should allow me to control 16 servos, and three of them should meet all my needs.
I'd also like to have a variety of sensors on my robot. Since there are a limited number of input available on the Arduino, and I'm already planning on using the I2C bus, I'm thinking that a few of these will allow me to get analog signal values into the Arduino via the I2C bus pins. Since the servo controller, and the DAC both use the I2C bus will I be able to have them both on the same line? Each of the DAC boards can only support two analog inputs, and since I can only daisy chain four of them together it might be best to have multiple I2C buses running at the same time. Basically, having one I2C bus on one pair of pins, and another on a different pair of pins. Can I do this on an Arduino? Are there better DACs for the Arduino available?
I would eventually like to create my own circuit boards, such as this. I'm thinking that mastering the I2C bus methodology is something I'll want to do. The article I just linked to does a fair job of explaining how I can use an IC to expand the I2C bus outputs. Is there a similar tutorial available for creating an expandable I2C DAC set up?