Let's Make Robots!

What transistor to use?

This is a pain in my ass: I'm building an H-bridge to power a motor which draws 1.5A without load and 15A at stall when given a supply voltage of 8V. I'm using two NPN and two PNP transistors. I'm using +5V as high signal. I'm going to use PWM on this thing. Can anyone here adivse me on what transistors to use? I'm searching on this for days.


Just ordered the following:

Arduino UNO, Arduino xbee shield, 2x xbee 1mw, Sharp IR-sensor, 2 joysticks!

And I can't wait for it to arrive :D

Xbee ADC

Ok, so I'm working on a plan to bring my little brother's little Niko RC car (you know, these models that suddenly break down for no reason at all after three charges) back to life. The plan is:

Two I2C-slaves ==> i2cslave-command repeated?


In the near future I'll have to control 2 MD03 motor controllers via I2C. Now, I don't get much about the i2c-commands integrated in PicAxe µC's so I'd like to ask how I should talk to them. Should I issue the i2cslave-command everytime I want to speak to one, or should I issue it twice (euch with another address) in the beginning of the program, or is there another way that I don't now about?


Problems with I2C -- DISCARDED

I'm trying to control two motors  by means of a joystick. This means I've coupled the potentiometers inside the joystick to my Picaxe 28X1 and my Picaxe 28X1 to two MD03 motor controllers. 

While testing I'm using only one potentiometer and one MD03. The problem is that I cannot get the system to work.

The program I'm using right now is:

i2cslave %10110000, i2cfast,i2cbyte


readadc 0,b0

Motor drivers?

Does anyone know of high current ( 2.5 Amps per motor) motor drivers which are compatible with Picaxe AND PWM? I need to drive 2 motors.

Motor and wheels

Hi there,

 In a current project (for school) I'm in need of a pair of wheels and matching motors... 

I've had a look at this page, but they look a bit small (don't know the measurements) and weak... I need a pair of motors and wheels that can support about 20-30 kilo (44-66 lbs) at least... any suggestions?


Thanks in advance! 


AXE 045 RGB sensor


 Does anyone around here have any experience with the AXE045 RGB-sensor from Picaxe? I connected it to my Picaxe 28X1 microcontroller and I am only able to get readings from about max 40 for red and blue, green only gets to one or, if I shine directly into the lens with a flashlight, up to 9.

 Any help?