The Fitzy and Carraldo Project
This is an ongoing, long term project. Each section will address a particular aspect of the robot design such as the motor control or various sensors. The hardware will undergo revisions I'm certain. As I implement features I'm sure to find errors or potential improvements. When the project reaches beta (feature complete) I will post the hardware schematics, PCBs and software. Occassionally there will be overall progress reports on interesting developments in Fitzy and Corraldo's behaviour. All in all, it should be a fun adventure. Jump to the latest post.
What does it mean to be a robot? What does it mean to be alive? In this opening post I present my thoughts on the subject and discuss what I'd like Fitzy and Carraldo to become. I talk about how I envision them as being different from the primitive robot I built in 2011 and hopefully better.
Fitzy and Carraldo are twin robots. In this first hardware post I will summarize the hardware plans that I set out in my March 2012 Robot Project Post. Although somewhat redundant, it provides a more concise summary of the previously posted material.
The biggest problem with many DIY robot drive systems is that they have no feedback. They trust that the motors are performing as expected. By adding optical encoders Fitzy and Carraldo will have real knowledge of their movements. This will be critical for both navigation and local sensing. Here is a diary of my steps and missteps.
On robots of this complexity I/O lines are always in short supply. I've used parallel LCD displays before
but couldn't sacrifice so many lines for a display that might not even be used during normal operation. So I hunted through the available serial LCDs looking for potential bargans. They tend to be a bit pricy. Here are my experiences
with the NHD-C0216CiZ-FSW-FBW-3V3 NewHaven LCD.
Tracking what's going on inside your robot is difficult at the best of times. Perhaps you have an LCD display, or a serial connection to your development machine. At some point you'll have to unleash your creation and let it roam free. I added a wireless transceiver module to Fitzy and Carraldo so I can track what the sensors are reporting and more importantly what the robots are 'thinking' and what they had deduced about their environment.
The mRF24J40MA wireless USB
dongle is done. Fitzy and Carraldo got wireless transceivers so they can communicate with each other. Now my PC can join in their conversations.The wireless has already
proven invaluable as I troubleshoot elements of the robot design. My next project is a wireless remote station that you'll be able to control wirelessly from your PC.
Projects seem to be composed of a series of loosly related tangents that eventually culminate in the thing you're trying to build. In this project update I take some time to build a buck regulator to convert my ~10.8V battery supply to the 6V Fitzy likes to eat. I managed to destroy two commercial units so thought this was a sign to learn how to build my own.