Let's Make Robots!

mosfet problems

I am having trouble with a project and hope someone can help. I have a pwm motor speed controller I bought from Carl's electronics (see http://www.electronickits.com/kit/complete/motor/ck1400.htm). I put this together and it works fine. Then I rigged a n channel mosfet to turn on and off from a rf receiver signal, with just the motor this works fine. Flip the receiver on the motor goes on, flip the receiver off the motor goes off (I used the mosfet circuit in this post from LMR http://letsmakerobots.com/node/4285).

Robot position with quadrature encoder

I'm building a robot for environment mapping. It's a simple "start here"-class robot: 2 wheels, 2 dc motors and a range sensor mounted on a servo. I plan to hook it up with my PC 1st by USB and later on by wireless somehow.

I want it to drive around and send the range sensor readings to the PC which in turn will be building a map of the environment. The hard part will be knowing the robot's position relative to it's earlier position(s). I know this would be easy with a GPS or an accelerometer, however I wish to find a more lowtech/DIY solution, so here is my idea:

Should we kick out vendors? Please vote!

Question: Are we seeing too many vendors on the pages, making challenges and pretending to be friends and stuff?

Write ***Y in comments below to vote Yes to the above question

Write ***N in comments below to vote No to the above question

We ARE planning to see lots of vendors products in a new components section that we are working on. But I am sure that will just be nice for all of us; Cool products nice to browse, and a nice place to showcase what you sell (unlike now where it is a not so nice list)

Regarding Robots which uses GPS tracking...


I am new to this forum, and I want to submit a project to school on Robots.

Aim: To feed the destination address like NMEA code to the controller and it uses GPS receiver to know its present position and compare with the destination address and move to the destination address specified by using stepper motors..

 Can u pls guide onthese..

How to decide about stepper motors and controllers I thought of using ARM7 whether its OK or not..???

PLease guide me...

Putting voltage through a photo cell and to motors?

While I wait to get some real parts, I've been tinkering around a bit. I made sure that one of my photocells could endure 9 volts without exploding (out of voltage regulators), and connected it to a buzzer and battery to see what would happen. It worked pretty well, and I found that the more light the photocell took in the more power the buzzer got (and thus the louder it got). However, when I replaced the buzzer with a small motor I got nothing. I tried a few other motors and still wound up with zip. How to I make the motor spin faster as more light is taken into the photocell?

Parallel port control for a Mac

Anyone have experience with controlling a parallel (8 or more lines) output on a Mac (OS X)? I want to control my CNC machine with a parallel interface but Macs don't have parallel ports anymore. I need to find a suitable replacement, but a serial port/MCU would drastically complicate things. Please help! What hardware should I get?

Posting a robot page from DAGU

I was a member of LMR well before I ever heard of DAGU, I miss posting robots but have refrained from doing so in case others felt it was spam. It seems to me if I show the work that goes into making a DAGU robot, from idea to prototype to final product then it should qualify as a robot page as well as a component from DAGU.


Are my designs robot page worthy or advertising?


Robot parts in Finland: Robomaa.com

Hello to all! I'd like to introduce to you Robomaa.com, Finlands first and only webshop focusing on hobby robotics products.

Our goal is to provide easy shopping experience at affordable prices to all robot-enthusiast in Finland, from hobbyist to hobbyist.

Servo controller using timeframes

I have four servos with the following specs: