Let's Make Robots!

Video for robots

I would like to build a robot that uses a video camera, processes the data, and then reacts to that data. Basicly I want to be able to designate a destination using a laser and the robot will chase the laser. I do not know what sort of micro processor I will need for this and also I do not know what kind of camera will work.

 I have been looking at the parallax propeller as a possible processor, but i do not know how to interface a camera to it, or servos (which I also need to control).


I recently bought a pololu 3pi robot and tried programming it with a USB Programmer, but couldn't get it to work with Arduino.  Does anyone know how.  Its this -> http://www.makershed.com/ProductDetails.asp?ProductCode=MKPO2

where to find a specific DC motor

I just found this two rc cars, and I want to give them a new life. The small one seems to be working ok, but the motor of the biggest one doesn't want to work.


I removed the dc motor and noticed one thing I never saw, there are the two wires that connect to the motor pins, and there was a third wire but got loose. I think it was soldered to the motor body, and I wonder where must it be connected.. ground? I try to ground it but the motor still doens't work.

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.

High signal from pic to pic w/(2) pwr supplies?

So here we go:

Walter has (2) 7.2v  packs, one for data and one for servos. Each has a switch and can be turned on idependantly (manually). During the "start-up" routine, I need the main picaxe to know if and when the servos have been turned on. It would be like this:

I turn on the main brain. The LCD turns on and displays a message to tell you to "turn the servos on, please" --I need the main brain to know when you have turned them on. 

A multimeter question

Quick question- Why is it that when I set my multimeter to 9v battery it says my solar panel is putting out 0.89v and when I put it to 20v (not battery)  it says my solar panel is putting out 2.10v?

lithium batteries

I bought some li-ion cells for a dollar a piece and was hoping to use a couple in series to give 7.4v. However they do not want to co-operate. When I connect them in series the voltage just dies to millivolts?

Individually they work fine putting out 3.7v and although I haven't discharged one fully yet I suspect they'll run close to the 670mAh they are rated at. 

IS there something specific to li-ion batteries that you can't just hook them up in series like other cells? This one has me puzzled. If I can't work it out I'll just have to do a booster I guess.

motors and amps

hay, during building first robot i had some difficulties with my power source , my setup was basicaly a start here robot but with arduino  i used the l239d motor driver , my power supply was a ni-mh 9v rechargeable battery powering arduino, and 3 AA battery pack to the motor driver


my problem was my motors runing weakly, or slowly ( they are gm8 solarbotics motors ), this did inprove slightly when i switched to the battery source mentioned above .


DIY not gate


i tried building a not gate (1 input only), not one i saw on the internet but i tried to make one myself. The problem is i didn't succeed. Now, i know there are loads of examples of how to make one on the net, but i opened this post because i'd like to know why mine doesn't work, so i can improve, hopefully :), my electronics skills.

Here it is:


CNC lead screws

Im looking to find some cheap lead screws ( http://en.wikipedia.org/wiki/Leadscrew) online . I was wondering if any one could point me in the right direction to find some cheap lead screws. I would guess that the CNC guys would know where to find them. If any one could give me a suggestion on which lead to use, i would appreciate it. I think i want a lead of about .500" per revelation. This is for my chess robot. I do not want it to be too slow.