Project Update

A pictorial update of my current projects.

From Project: Burt

Watterott RedFly-Shield connected to a GHI FEZ Domino.
Serial snooping via a Sparkfun FT232RL Breakout board.

From Project: Burt

GHI FEZ Panda. Single row right-angle header allows for the Mode pin to be grounded.
Double row right-angle header underneath the board exposing the JTAG interface.
Not show: Olimex ARM-USB-TINY JTAG dongle.

From Project: Burt

Simple Inertia sensing. I2C temperature sensor. UART and Reset control of the motor controller. Futaba servo mounted and ready to connect to a distance sensing array.

Sparkfun WiFly shield with FEZ Domino

After getting the Motor Controller interfacing completed I decided to join the few others that were developing an interface between the FEZ Domino and the Sparkfun WiFly shield.

The class libraries and firmware from GHI and Microsoft are limited in what devices they support. Unfortunately the WiFly shield is not catered for yet. So we need to create Managed code to drive this shield on the FEZ Domino.

It's a different story with the FEZ Panda and the ability to add Native code to custom firmware (at the expense of GHI Native code assemblies). I'm curious as to whether the Panda can have a TinyCLR build reflashed via JTAG and OpenOCD considering Code Read Protection is enabled in the LPC2388. You can bypass this procedure and purchase a CRP disabled board straight from GHI.

The first step was to make the WiFly shield pin compatible with the FEZ Domino. Others on the TinyCLR.com forum had found a number of ways to do this. I opted for adding a diode between the 5V and Vin pins. This would allow me to use USB to power the Domino and Wifly shield, plus the option of running the Domino from an external power source.

The next step was to sort out the code to handle the SPI to UART bridge. Getting the signal and startup sequence nailed others had managed to deal with. So it was fairly quick to get the WiFly-GSX chip into it's command mode.

Once in command mode the lengthier task was then getting the UART to talk properly, and deciding what state to get to with the WiFly-GSX initialisation and WLAN connection configurations.

I created a custom class library for all of this. This source code, and example usage code, can be found over at Fezzer.com (Sparkfun WiFly shield with FEZ Domino).

Project: Burt

Introduction

After a couple of years of life changes, the itch to revisit robotics has taken hold. The first robot was something that I rushed into and made some crutial, and costly, design mistakes. This time around I have had time to revisit new products and come up with a new robot design, 'Project: Burt'.

It's been great re-visiting web sites and forums I have been to before, such as Sparkfun and Pololu. It was also encouraging to find two UK suppliers that I hadn't seen before, namely Cool Components and SK Pang.

Being away from the home-brew robotics community, for almost a year and a half, has meant that I had some catching up to do with the evolution of robotics parts. Immediately three parts jumped out at me; Robot Rover for Arduino (Tank Kit), Serial Controlled Motor Driver (ROB-09571, ATMega328), and the Arduino Duemilanove (ATMega328).

The ATMega328 used in the Duemilanove and Serial Controlled Motor Driver (SCMD), looks like a perfect micro-controller to use as a sensor analyser and communications hub. Plenty of digital IO and analog inputs to play with. It was a bit overwelming, and warming, to see the rise of the Arduino products. A heathy development community has sprung up. As I thought about various sensors, controllers, communication sub-systems, most of my questions as to what to use, and how to use/connect them, were answered via Arduino's wonderfull web portal and forums.

Design List

Within a few weeks my thoughts for 'Project: Burt' were starting to come together. As a starting list I had the following in mind;

Arduino Duemilanove
- As the main controller.

Robot Rover for Arduino
- As the main chassis.

Serial Controlled Motor Driver
- As the motor controller (incl. overcurrent detection).

Pololu Pushbutton Power Switch LV
- As a potential power switch for the motor controller.

Dimension Engineering Accelerometer (DE-ACCM2G)
- A buffered ±2g accelerometer based on the Analog Devices ADXL332.

IR Range Sensor (Sharp GP2Y0A21YK)
- Included with the Robot Rover kit.

Ordering

Two orders later, I have a desk full of parts :)


Included in the orders we're a handfull of other goodies; An Arduino Starter kit (C), an Arduino ProtoShield Kit, and a couple of MCP23008 and MCP23016 IO extenders (with I2C interface) for future expansion (e.g. LED segments, Servos, USB host connection, VirtualCogs interfacing, etc.).

Physical Layout





The Arduino is placed on two stand-offs, so there is about a 1cm space below it to mount the motor controller. If any heat issues arise there are other mounting holes on the chassis to use. But for the moment this looks like a good starting point.

The main boards that need individual testing;


And so, it begins

Over the next few weeks (months) I'll be continuing along like my first robot blogging. Fleshing out the Google code project with links, Arduino PDE code, Eagle schematics, more photos and videos. A detailed step-by-step guide to getting Burt up and running.

Unlike the muddled mess that was my first robot, Burt is so far shaping up to be a nice project to get back into robotics. Plus a new starting point for vision experiments. Maybe I'll be able to get the old Virtual COGs boards dusted off and make use of the lovely Freescale i.MX21 266MHz ARM9 processor, and maybe save up for something like the Surveyor Stereo Vision System...