DISCLAIMER: This is not a completely finished project, it works but has flaws in code that make it a very slow tracking movement and only in the x direction.
The overall idea of our project was to pop balloons just by turning on the machine. We did some searching of the internet and found out that people have done similar things using Raspberry Pi's, Arduinos, and cameras. We decided to go with the Arduino. Some other things we knew that we would need right off the bat is two stepper motors; one for the x-axis swivel, and one for the y-axis swivel.
Small machine bolts and nuts, 2 stepper motors, stepper cylindrical extender, small bracket screw, 90 degree corner bracket mount for top stepper, flat stepper mount plate, 1 protoboard, 1 arduino, 2 L298N chips, 1 USB camera (we purchased one from Walmart for $24), 8" diameter acrylic circular plate, 3 ball-bearings and encasings (for acrylic plate stability), all different size drill bits, 4 OpenbeamUSA.com 5" connectors and their corner joints, and 2 10"x10"x1/2" particleboard/plywood sheets and 4 legs to separate the boards (wood cut to length depending on size of bottom stepper).
Step 1: Creating the Base
1. We began by making the divider for the base. I have to admit, we found our base already made out of scraps in our class room, but it is a very easy-to-recreate design. Stick the bottom stepper to the bottom board using duct tape and attach the cylindrical extender to it. Measure to the half-way(ish) mark of cylinder from the bottom board, this will give how high the upper board should be from the bottom. Then cut a 1" diameter hole in the center of the top board for the cylinder to stick through. Cut out the four legs to connect the top board to the bottom and screw them in accordingly.
Step 2: Creating the Acrylic Circle
In our class room, we have a laser cutter that we used to cut out the 8" acrylic. Once this was cut out, I drilled a hole in the center to put the small bracket screw in to attach the base to the little cylinder on the bottom stepper, as well as drilling 6 3/32" holes on three different parts of the edge of the circular base to attach the ball bearing encasings to add stability. Attach the circular base to the cylinder of the bottom stepper and the bearings should just touch the wood (this took lots of adjusting up and down to get to fit just right).
Step 3: Creating the Tower
Refer to the picture on the overview if you need visualization. Now we make the upper tower on which to mount the y-axis stepper. For this we just make a square of OpenbeamUSA.com 5" beams with corner brackets and screws that come with them. On the top beam, mount the stepper motor with the 90 degree corner bracket and mount the camera on top of this, and on the bottom, put two screws on the post and drill two more holes in the acrylic to fasten the tower down tightly. On the end of the top stepper, mount the plate and zip tie the laser on to it.
Step 4: Wiring the Arduino, Laser, and Steppers
Now the construction of the laser is complete and now the wiring begins. We were originally planning on just using Arduinos and protoboards, but then we decided to use L298N chips for the steppers and this made our lives much simpler. Just look up the schematic for this chip and follow our code for the pin numbers to use for easy wiring.
Step 5: Download the Code
From this guide, which is a little open-ended on some measurements to allow you to make it your own, you have just created color tracking laser turret!