Still Going!

As can be seen from the photos I decided to go with 2 motor drive with trailing castor wheels.



The motors are Pololu 37D with integral reduction gearbox. These are directly driving onto 80mm solid tire wheels. Most of chassis base is angle aluminium pop riveted or screwed.

The metal frame is the chassis from an old HP vacuum tube voltmeter.
Chassis construction began in 2013.





Currently the front of main frame has an RFID switch (from a previous project), then an AVR controller & display, and an Arduino UNO board (which will be running Forth). Base of chassis will hold two LiPo batteries (same as used on large model aircraft) and drive motor power controllers.



Veroboard mounted on the side of chassis is for additional circuitry as required as project evolves.



Rear of main frame will have voltage regulators and power switching.
Front of base has main battery isolation switches and just behind these are isolation links for the drive motors.

Hoping by the end of this year to have all power supply, voltage regulators , and battery charging circuitry finished.

I'm still planning to use the Alix3d3 running linux. This board will provide remote access (WiFi link to Alix3d3 board), and control functions via the USB interface as shown on first post.



I have had a Uno board running simple Forth program to flash out S.O.S. on board mounted LED.
Forth compiler is SwiftX-Lite-AVR. I like this product, https://www.forth.com/embedded/ , easy to setup, good documentation, etc.

Following link shows short video of Uno board, and IDE. More to come later.
https://youtu.be/t6F7-tCOkyY

Plan A, Part 1, Step 1. In the beginning.......

As mentioned in the blog description the plan is to work towards having a robot that autonomously moves, avoiding obstacles, and eventually performs a useful task.

I have chosen to start with an Alix3d3 single board PC from www.pcengines.ch
This board is available in Australia from www.wifiproducts.com.au

Initial task was to get the Alix3d3 single board PC to communicate with Open-USB-IO board, switch on lights, read the state of switches, and measure voltage level at analogue inputs.

Alix3d3 is running the 'Voyage' linux distro which is debian based. Check out http://linux.voyage.hk/

Open-USB-IO is an Australian open source (software & hardware) project. Reference for more information is http://pjradcliffe.wordpress.com

In the attached picture you can see illuminated LEDs on the USB-IO board and voltage reading at the multimeter.
The Alix3d3 is in the bottom left of the picture, and the Open-USB-IO board just down from centre.
Alix3d3 uses compact flash for program memory, has a VGA output, and can be accessed via either serial port, or USB keyboard. It also has audio input / output ports.

Next I will be looking to re-house the Alix3d3 and USB-IO board and try and get back in to Python to see how I might be able to control the IO board from within Python.
In addition I need to decide on a layout for the robot. I am not sure yet whether to go with the popular two wheel, two motor drive combination with free castor wheel or something different.
Size is another consideration. Making the platform big allows for expansion and provides flexibility, keeping it small makes it easily portable, reduces power requirements, etc.