I finely got some spare time to start working on C/C++ embedded systems and robots. So in browsing around at Radio Shack I stumbled upon the Make:it Robotics Starter Kit. Apparently a joint collaboration between Radio Shack and the folks at Maker Media, Inc. The same people who bring you Make: Magazine.
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Step 1: Line Following Robot
When I got home I quickly broke open the box and started looking over the contents. The kit comes with everything you need to build two robots with the exception of an Arduino Uno and 8 AA batteries.
In Starter Kit you can build either a line following robot or a walking robot. I choose to build the line following robot first. It took me two leisurely evenings to put the robot together. The assembly instructions were great. All of the robot parts were first class, the robot frame is black powder coated metal angle and flat brackets, similar erector set style.
The only plastic parts were the battery boxes, the wheels and the motor cases. The only comment was with adult sized hands it was a bit tough fastening the corner nuts and bolts. But if you are assisting your son or daughter with the building steps, this will be great for little hands. Once you finish building either robot, there is a link in the manual where you can download the software for the robot. Within this download there are some example programs, a readme file, and circuit diagrams for the sensors and motor/sensor shield. There is no documentation available concerning the hardware, consisting of an Arduino motor driver, sensor shield. In order to get the specifications you must read the schematic.
For the person who wants to take the robot building process further than just assembling the provided kits and running the provided software, there is little information provided. You must figure this out for yourself, by reading the schematic, a bit daunting for someone just starting out with electronics. Loading the line following program, to the Arduino is easy using the Arduino IDE or if you are an advanced user you can use one of several available development packages such as the freely available Atmel Studio, which is what I use. In my next post I will go further into reverse engineering the software provided.
After tracking down 8 AA batteries my robot was ready run run. The Make:it Robotics Kit even comes with a sheet of heavy duty white paper with a 360 degree circle for the line following robot to follow. The instructions indicate that the optical sensors that come with the line following robot are very sensitive to light an if the robot is not functioning properly to lower the ambient light around the robot. I placed the robot on the white paper just off of the black circle and turned the robot on.
My robot would only make it about 1/4 the way around the circle before loosing track of the black line. I tired several times, but still no luck. I turned off the room lights and tried again. Still no luck. I double checked my wiring and everything was wired ok. But the best the robot could do was only make it about 1/4 around the black line circle. Time to do some modifications: Here is an image of the stock robot with the sensors exposed to the ambient light.
Step 2: Duct Tape?
I have played around with line following robots before and there is a trick to shield the sensors to the ambient light.
So I took some duct tape and covered the sensors from the top.
After this modification the robot was able to make it 3/4 of the way around the circle, ambient lights on or off, better but still not good.
Step 3: Sensor Height
Time to do some more hacking.
The kit comes with some additional parts for the walking robot. I noticed that there were some shorter posts, (referred to as “Column B” in the manual). So I changed the longer posts with the shorter posts thinking this might help with optical sensors. Nope it made it worse, But the change was less than 1/4 of an inch. So I tried something else. I left the shorter posts on the robot and added 1/4 posts to each post. I picked these up locally at Fry’s Electronics. Radio Shack did not carry these parts in the store.
Fired up the robot and success, ambient light on or off the robot was able to make multiple passes around the circle without loosing it way.