Let's Make Robots!

Anybody know anything about building amps?

I've recently come across some fairly nice sized speakers that I'd like to hook to my TV.

But, I thought it would be cool to build an amp for them myself. They're unpowered, which means there needs to be some sort of go-between from my TV to the speakers to give them enough power.

I've done a little googling, but the most I am coming across is little altoids amps for headphones - which isn't what I'm after.

My thought is though that I might be able to take one of those schematics and upgrade the parts to a higher voltage... I'm not sure really.

Motor Controllers For BIG Motors...

Hey all,

I'm working on building an electric bike... well, doing the research for it anyway.

Right now I'm thinking about motor controllers - which are pretty expensive to buy already built.

My thought is that I could just build my own. I'm just not sure if I could use the same schematics for an h-bridge, but just upgrade the components to ones rated for higher voltages.

I'll be working in the 24V to 36V range if that helps at all.

In my head there's no problem with it... but then again I'm still pretty new to the electronics bit. 

Need A Bit Of Transistor Help...

Okay... I'm going to try to explain this the best I can...

I'm working on bypassing some switches in an RC remote, SPST switches I'm told. (See this thread for info about the switch http://letsmakerobots.com/node/17951

I've got two wires soldered to the switch, and when I touch them together, the RC car goes forward as planned.

Now, what I want to do is use a transistor (I have both NPN and PNP) to automate the "touching of the wires" via my Arduino.

Information about this switch?

Hey all,

I'm looking for a bit of information on this switch.


Namely about why the 4 leads.

I'm working on bypassing the switch in a RC remote with a transistor so I can control it via my Arduino with a simple pulse.

However, since it has 4 leads, unlike a regular switch... I'm not sure where to begin looking for information.

Another H-Bridge Post

Hey hey.

So, it's my turn for an H-Bridge post.

It's a simple one too - I'm looking for a circuit that I can build without confusing the heck out of myself.

I've gone through about 6-7 different articles (with schematics and the like) about them, and understand the concept behind them. I've even tried to put a few together, but have had zilch in the way of voltage flowing out the other end.

This circuit is the one I've tried three times so far, as it's the only one I can find that specifically uses a breadboard.

Learning Electronics

Over the past weeks since I got my Arduino, I've learned a lot about circuitry. However, I still get headaches when I see schematics - and I'd like that to change.

What websites/books/PDFs/whatever would you recommend for somebody who's new to circuitry? 

Accessing an array's size in C? (Arduino)


I'm doing a little series of flashing LEDS, sort of like the knight rider examples you see everywhere.


Anyway, I'm trying to make sure I've got clean code - and from what I understand of C, this is valid. However also from what I understand, the Arduino uses it's own form of C, so certain things are bound to be a bit different.

Here's the code I'm having trouble with.

How to use solar panel?

I bought this the other day -  http://www.radioshack.com/product/index.jsp?productId=2062564 to use for a beam bot. Problem is, it was very cryptic with the intructions, so I'm not sure where to solder to for + or -.

If anybody has any experience with this, I'd love to hear your thoughts.


Just bought a dual PC board... I feel dumb.

Hey guys.

I just got home from the rat shack with a few of these babies.


Nobody in my town has breadboards, so these have to do until I get one from the net. Anyway, I'm pretty sure I get the idea of how to use one, but I'm hoping to find a short tutorial on the basics of using it. I know they're cheap, so I can screw one up and it's a non-issue, but I'd like to avoid that if possible :)

Which microcontroller?

Let me start out with saying that I bought a Picaxe about a year back and had absolute horror getting it to work with my PC. Nothing I did would work. I've been traveling for a long while now and am finally settling back down a bit, so I'm wanting to get started back in robotics.

I haven't built my first bot yet, but will be buying supplies soon. Can anyone recommend another MC instead of the Picaxe? Maybe the Arduino? Preferably something that has a good support group I can go to if I get stuck... which is more than likely.