Home Made R/C

[srobot]

Hi,
I was wondering if how to make a speed controller, a receiver, and a transmitter. Is it even posible to do it?

thanks
--srobot

[TheDuck]

Well, it's certainly possible but I get the feeling you'd want to just go to the hobby shop or eBay and get one there.

Since you bring it up, though, you could have some fun with it. For example, radio seems the obvious choice but why not light (except for the bit about line-of-sight requirements). Or how about sound? It doesn't even have to be in the human audible range though you may drive the neighbourhood dogs insane.

Now, as for the particulars about building any of the above, that would be interesting indeed. I'll be curious to hear whether you decide to take on the challenge.

[Kevin Berry]

ESC's schematics are available all over the internet, would be a great project. If you are thinking about a radio Tx/Rx, there are a BUNCH of pesky FCC regulations to consider. As El Pato mentioned, light or IR or sound would be cool, and legal.

[TheDuck]

...As El Pato mentioned...
LOL

El Pato comes from Canada so it would have to be Le Canard.

[Kevin Berry]

Duck, "made ja look!" ha ha

Here in Central Florida we speak a LOT more Espanol than Canadish! Even though our lagoon is full of sailboats flying the Maple Leaf this time of year.

[wrighthobbies]

You can take a more "robotic" approach and use a couple of small microcontrollers with a wireless link instead of duplicating RC. Replace the electronics of an old RC controller and interface the joystick pots and the buttons to an mcu and use a pair of inexpensive XBee modules to create a wireless serial link. The beauty of something like this is the freedom to interface any combination of digital and analog inputs. Plus, the communications can be both ways, allowing you to show data on the controller; battery low warning light or over-temp warning light, etc.

Might be easier than building a RC transmitter, receiver and ESC from scratch.

[dporter]

That's sounds easy enough, but for someone that hasn't used MCU's or XBee modules before where can you get the information to get started? It does sound like a good way to go, I'm just not sure how I would begin if I tried to do something like that.

Thanks

[wrighthobbies]

I'd start with learning microcontrollers. They are universally useful for just about anything and they can be had pretty cheap.

The Basic stamp isn't cheap but it's a great way to learn about MCUs. The cost can add up if you use a lot of Basic stamps. My first robot was a cheap RC truck with a BOE velcro'ed into the cab. I put a 12v lead acid battery in it and it flew! It was too fast for the sonar sensor on it so I eventually hit one too many walls with it :)

I now prefer Atmel AVR chips and you can find 8-pin and 20-pin versions for $1-$2. You need a programming cable and the software and you're good to go. Both PIC and AVR microcontrollers support in-system programming which means you can add a programming header to your circuit and won't need to pull the chip in and out of the board.

You can build a simple AVR programming cable for about $5 or less or you can buy one from $10-$20 online. There is a free version of Bascom that allows compiling of programs up to 4k (many chips don't even have 4k, this is a nice deal). You can use it with all the AVR chips but you wouldn't be able to use all of the program flash on the larger chips. The tiny13, Tiny45, Tiny2313, Tiny26 and Mega48 are all great microcontrollers with 4k or less of flash program space.

Once you get familiar with MCUs, it'll open up a whole new world of robotics. Heck, I hardly use logic chips any more...

[dporter]

Thanks, that helps.

AVR chips have popped up in a couple of discussions now so I'm really starting to get interested. I'll have to do some more research, but the cost seems right for experimenting and giving them a try.

Doug