I successfully took a cast-off toy robot that I got from the thrift store for $5.00, added sensors and a microprocessor and turned it into a self-directed line following robot. In December, I was browsing the the Arc, looking for something that would make a good project when I found a Robosapien V1.
At the time, I had no idea what it was or did but it was heavy, shiny and only cost five dollars so I brought him home. Turns out that it is a fairly high-end, remote controlled robot. When new, they retailed for around $100. I figure a 95% discount was a good deal even if it was missing the remote.
A little Google-fu quickly showed how I could tap into the existing control system and add a second micro-processor. By adding an Arduino as a Master Controller and soldering a line to the wire that connects to the built-in infrared receiver, I could make the robot think that it was receiving commands from the remote control. With that, I could make it walk, wave its arms or make various noises. All that was missing was a purpose. A mission. What would it be?
Not having anything against people named Sarah Connor, I skipped the whole Travel Back In Time And Change History To Ensure The Rise Of The Machines thing. Instead, I decided to add some infrared sensors to the feet and turn him into an entry for an upcoming Line Following Robot contest that my employer is hosting.
The first step was to tie in some lines to the existing control system for power, ground and the control signal. Opening the back and accessing the control board is pretty simple. Some more Google-fu and a little time with the multimeter let me identify ground, the 6 volt unregulated supply, the 3.3 regulated supply and the control line. I would like to take a lot of credit for that amazing piece of work but the control board is labeled pretty well so it wasn’t exactly rocket science. So I soldered in the new lines, drilled a hole in the body for the cable to run through and put him back together. A dab of hot glue where the cable runs into the body provides strain relief.
Next I had to mount some sensors on the feet. That wasn’t technically difficult but the placement of the sensor is crucial to his line following performance and the place I wanted to mount them was not structurally viable. So I had to add a Flexible Support Structure to both feet. (That’s Big Words for using hot glue to attach a strip of plastic on the front that I could mount the sensors on.)
After that, I was ready to take the lines from the robots innards and the lines from the sensors and hook them up to a suitable micro-controller. I started with an Arduino Micro since it is easier to work with than the Trinket. After I got all the bugs worked out, I ported the code to the Trinket. And as they say, it was just a Small Matter Of Programming and Voila! It all worked perfectly the very first time. (For some definitions of “first”) 🙂
The cost for the hardware is very reasonable. All told, I’m into this thing for maybe $20. Of course, if you factor in the amount of time I spent working on it, the cost would sky-rocket. Fortunately, I work cheap when I’m having fun. It probably shouldn’t have taken as long as it did to build this but I was treading some new ground in my personal knowledge quest and figuring out new things can be very time-consuming.
One of the following videos show the robot standing there looking cool and the other shows him “racing” around the track. So make some popcorn, pour yourself a soft-drink, send YouTube to the big screen TV and enjoy the show.