I started building a delta robot a few days ago with the intention of using it as a starting point for a more complex robot down the line. Life has progressively gotten in the way, but I wanted to share my status partly in hopes that it will push me to continue making progress, and also maybe to inspire someone else.
First off, I’m using an Arduino to control the servos. The actual calculations are done in Processing on the PC, and sent over to the Arduino through serial as a set of angles for the servos to hit. Eventually, I’d prefer to send more basic commands (X, Y, and Z) over the serial and have the Arduino do the math to calculate the required angles.
As part of my self-imposed limitations, I’ve decided to keep costs as low as possible, since eventually I will be building 4 more of these to finish out the prototype ground soldier for my future robot army.
So far I have the servos, Arduino, custom interface board, and wiring in place. The servos are mounted around the perimeter of a CD. I was looking for something rigid, light, and about 5” diameter. It turns out a CD works perfectly, and at a cost of about $.40, it fits into my cheap critera as well.
I’m working out the armature so that I can keep the whole thing light but strong. I’ve gone with 5/64” aluminum wire. This can easily be obtained from (of all sources) ordinary wire coat hangers. This stuff is flexible enough to be easy to work with, but at lengths less than 7” it is strong enough to hold shape against most reasonable stresses. I bent the wire with 3x90deg angles to form a sort of hook, then using a drill I widened the holes in the servo arms to accept the wire. This holds it well enough, but to make sure it didn’t flex laterally while in use, I added small zip-ties to add a little extra security.
Next up I hope to finish the arms, and mount a small plate at the top that will support a stepper motor, worm gear, and some sort of rubber tire.
So far, with the servos and Arduino, my total costs for this project are right around $75. If you got the same (or slightly better) servos online instead of Hobbytown, this could easily be put closer to the $50 mark. I already had the CD, coat hangers, hot glue, wires, solder board, and the various other pieces I needed. I expect to finish this project for less than $100.
I’ll post more as I have time to make progress.