Those black and white wheels are from a Desk Pets toy called a "TrekBot" I really like the hubless wheel drivetrain setup, and finally got around to making a little rover out of them. So here it is, 2 trekbot wheels [different colors 'cause the other white one broke :( ] hot glued with some hobby sticks to a Project enclosure, with a little caster ball holdung up the rear.. front.. not sure yet which end will be which.
"IGOR!! Bring me ze brains!!"
These are "the brains".. well, robot version of brains. After seeing how the remote control of the cheap little toy car I tore apart was, I decided to keep them for other uses.. since the 2 channels transmitted were not in fact some complex variable proportional shenanigans.. but rather a "digital" on/off, in both directions... times two! So the brains on the left is a transmitter with 4 pushbuttons, and the brasin on the right is a receiver with 2 H bridges swapping polarity of the two motor plugs upon command. Here we see them stripped of their battery pack prongs and motor connectors, and also the power switch (which was JUMBO) hardwired to always be on.
"NO! zees vire here, dat one goes Zere! How many times must I tell you; do NOT cross the zappy bits with the squishy bits?!"
hookin the power posts up to my power supply, I checked at the "VCC" test point (so nice to have it marked!) to see if the thing has power. "its aliiiive!". I was pretty sure it was fine after I removed it, but wanted to make sure. Also, I needed to power it up to see which plug pin was technically "foreward", with respect to the motor it was powering.
After wiring up the receiver brains to new power source, I had to do the same with the transmitter brains... had a AAA battery pack around, to keep this part mobile. Here, we see me testing the motor out points, and finding the + voltage point when I press FWD on the remote (its upside down). This did a couple of things: prove the receiver brains were still working fine, as well as prove the transmitter brains were as well.
"Ve haff control" Using the spare black wheel left over, I tested the receiver brains to see if it was able to do a couple of things: A) drive these strange motors from another device with enough power, and B) see if the brains could themselves handle more power... like 9 volts. This was a gamble, but in the end I just told myself "so I will just be out $13.00 if it fries" and went for it. You can totally tell the difference twice the voltage makes... and hey! It wouldnt be a Frankensteins Monster if it didnt have Monster power, right?
And here will be the power for the little monster rover. A 9volt is really more compact than 3 AA that the toy originally required, and fits in the enclosure box nicely... I just wish the brains would as well... oh well. I quickly undid all teh testing jumper wires, and replaced them with the 9volt power supply, and soldered the wheel motors on with the correct polarity. As I couldnt wait... lets test it out!!
Like Frankenstein, its first steps were a little rough. It was confusing! Now instead of one set up buttons controlling fwd/rev, and the other left/right, now the left/right was fwd/rev of the other wheel! yet the buttons were sideways, and it wasnt very intuitive which way on those sideways ones was foreward... even with some practice. Still, the little monster has some power, poppin wheelies and such. And it certainly turns on a dime (that means I got the wheels positioned just right)... but the controller needs some work... if only they made spring loaded rocker switches, that would go back to center/off when let go...
(... they totally do). Again, the makers of these parts were polite enough to provide test points all over all of them, all the better to help me figure out which parts did what when I pushed a given button. After a bit of experimenting, it was simple- each button had a test point associated with it, that I could solder tiny wires to, to go up to the rocker switches. It wasnt pretty, but should certainly work better.
So lets try a final demonstration. This is what Toy Hacking is all about- taking some little electronics gizmo, using its parts for something else, and hopefully making something a bit better than the originals out of it all!
I plan on using this little guy as a test bed.. to try out new drive/steering/control schemes, from BEAM photovores to Arduino explorers, to whatever. Thus the box design. this remote control setup was just gravy, to let me put the chassis through its paces and see if it would even go in a straight line, or turn in place. It turned out just about perfect. and its certainly cooler than the original mustang toy that needed 5 feet to turn around.
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