This tutorial will show you how to make a very simple robot that will avoid obstacles on the ground. It uses no microcontrollers, no servos, and there is no need to program. The simple design make its an ideal project for those wanting to tryout robotics and also makes a great weekend project. After building one you can probably make a second one in less than 10 minutes.
This article was submitted by Emmanuel Carrillo as part of the “Hobby parts for articles” program. Emmanuel receives a Modern Device Company Bare Bone Arduino Kit for this great intoduction to robotics.
Update: Jerome Demers informed me that a very simular how-to was published as an instructable in 1999. You should take a look at his Beetle Robot Instructable as well.
2 – 1.5V motors
2 – SPDT switches mechanically easy to trigger
2 – AA battery
1 – AA battery holder
1 – Altoids Tin
2 – Wheels
Index Card or Cardboard
Depending on what you have lying around this should cost you around $5-$10. Mine cost me $6. You can get the 1.5V motors from the dollar store. The dollar store by me had two little “remote controlled” cars that each had a small motor in them. Switches for me were the only real expense, they were $2.50 a piece at radio shack. If you take apart some old electronic gadget, you can usually find them; old printers and VCRs are a great source of parts like this.
Hot Glue Gun
Dremel Wirecutters or Tin Snips
Here’s an overview picture (far right) showing what the insides of our robot will look like when we are done with wiring the parts together.
Solder together the top two pins on the switches together. Repeat with the middle pins.
Step 2 (right picture)
Solder together the two bottom leads on the motors.
Step 3 (below picture)
Solder a wire to the bottom on the battery pack as shown below.
Step 4 (right picture)
Solder the negative lead of the battery pack to the middle pin of a switch and the positive lead to the top pin of the other switch.
Step 5 (below picture)
Solder the bottom pin on each switch the motor on the opposite side. Then solder the other end of connection you made on battery pack to the bottom lead on one of the motor.
This is a good time to check everything. Install both batteries and check that both motors turn. When you click one of the switches the opposite motor should spin backwards. Before continuing to step 6, remove the batteries.
Cut holes for the motors and switches in your robot body. For this article I used an Altoids tin. Line the insides of the Altoids tin with electrical tape and cut an index card to place in the bottom of the tin to prevent shorting.
Un-bend two paper clips to make atennas and glue them on the switches.
Glue everything in place.
Tip glue in the motors at an angle. This allows the robot to sit off the ground higher, and allows you to use smaller wheels. I have found that smaller wheels tend to make the robot handle better. You can use whatever you want for wheels. At first I used Lego wheels but then switched to smaller wheels after not liking the way the robot moved.
Attach some wheels and let the robot roam free.