Let's Make Robots!

custom line follower problems[one IR led, is bright, the other two are dim]

Hi, i learned eagle basics, so as a first eagle project i made this line follower with sparkfun's QRD1114 IR detector thing.


the project is attached.


what could be wrong here?


from left to right the first QRD is dim, the middle one is bright, the last one is dimmer then the bright one, but brighter than the dim one :S



Converting a PIC program, to arduino C

Hi, i found this code on the net, but i need it in arduino C, i have no knowledge on it, and no idea where to start translating...

there is also this one, in basicstamp i presume...



DIY encoders for tamiya dual gearbox

Hi, Want to add encoders to my tamiya dual gearbox, since i'm using bulky opto switches, i have easy access to a gear that rotates 7 times per revolution of the wheel, i thought of making 4 holes on that gear(in a north, south, east, west orientation), reckon 28 pulses per rotation will be enough?

What should be the resistance between clock, and data on an I²C bus?

trying some i2c devices, though they aren't working, so i thought maybe they where shorting, my cheap multimiter reads 3kohm, is it suposed to be like this?

the device is a cheap ebay nunchuck, made myself a wiichuck adapter with vero board, though i'm measuring the resistance directly from the original socket, so it's not my homemade adaptor thats causing the probems...



i2c = PS/2?

Hi, can i connect i2c interface devices to my computer, by using the PS/2 jack?





Peculiar ldr problem...

Hi, well got my robot to follow light, to see if everything was working fine, but the weird thing is, instead of changing direction in real time, it only changes direction when i reset my arduino board, same thing happens if i watch the serial monitor.


for example


it prints out 500 to the serial monitor

keeps printing 500, even if i change the light source.

Arduino + a doorbell's wireless modules

hello, hope you had a merry christmas, and will have a happy new year!

I found a wireless doorbell, and i would like to know it it would be possible to attach the button of the doorbell, to the TX pin on the arduino, and the receiver to the RX pin, sorta like this:


I think i would then be able to serial print what ever i want, and serial read it with the other arduino. say controll severall motors, even if it just has one button, would this be possible?

Xbee modules help

HI, well, the free day is arriving, so i thought i'd go to sprakfun and fill my cart.

what exactly do i need to have wireless COM betwen two microcontrolers, or PC, to micro controller, or even stand alone Xbee's?

I have these items in my cart:

Can i control a servo with a 555 timer?


I would like to sweep a servo back and forth, and theres no point on using the arduino for this, and thats all i have at the moment, so if i supply 0v to the yellow wire on the servo(signal) and then supply it with 5v, then 0, then 5v again.... would it sweep the servo? or does it have to be modulated?