Wednesday, April 9, 2014

Rover Guts

How about some pictures?

This is the rover today; the new addition being the connectors on the mess of cabling hanging over the front end. Each one of them had to be hand crimped and soldered, and that's just one end of each of the cables.

For one half of the rover.

Ugh.

The bogie connection on the rovers left (photo - right) side is now a beefier 0.5" dia. bearing, which goes to a 3D printed shaft that drives a 10k linear potentiometer. The potentiometer is held to the frame with a 3D printed bracket.

Also 3D printed and barely visible here is a bracket on the rear steering motor for an ultrasonic sensor; it's the bit of red plastic just behind the bogie.


Most of the changes (and recent work) are on the inside, to the rovers guts.

In the image below, on the left side, which is the front half of the rovers electronics box, are all new brains.

Visible here is a GPS unit, sitting on a blue 3D printed plate, and under that is hiding the Beaglebone Black, which is sitting on a similar plate.

To the right of that are two vertically mounted PCB's; one is the carrier/connector/I2C interface for an ADC Mux Breakout (probably from Sparkfun, it's red), and behind that an Adafruit 16 channel PWM board.

At the bottom is a stripboard that has all the I2C bus connectors and the logic level shifter on it.

The four voltage regulators are at the bottom of the image, with some temporary wiring harness for testing.

One the right side is a mess of power wiring that I have to dress. Although the only change here is the addition of 2 fuses, it made a real mess of the power wires.

It also doesn't help that the user interface protoboard isn't screwed onto it's bracket, so it's just hanging around in the middle of the bay.

Below all that are the four motor driver PCB's. I'm thinking those will have to move out to the wheels to tighten up the feedback loop for speed control. I may also add two more, so I have one per wheel; right now the middle and rear wheels on each side share one driver.

That's it for now… hopefully in the next week I'll complete the wiring and get the I2C busses powered up and start writing some code!


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