Let's Make Robots!

How to power different voltage motors from same power source?

I am taking the "There are no stupid questions" comment to heart here.

I am hoping to power DC motors and servo motors from the same power source. The problem is, the servos want 6V and my DC motors are rated for 1.5-3V. A nice simple solution like a potential divider won't work, since each motor has a non-constant resistance, and a voltage regulator would be hideously inefficient. Adding a separate battery pack seems a silly idea, especially given the Arduino will have one of its own as well.

Send your robot to Maker Faire

Can't make it to Maker Faire this year?

Maybe your robot can!

Last year, quite a few people sent their robots to me to be displayed at Maker Faire. They were a big hit! I even made up some shirts to thanks some of the folk that sent robots from far away.


question on a h-bridge circuit I found on this page

Hello everyone,

well, I´m pretty new to this community and I hope this post is not too dumb in your eyes. I´m more at home when it comes to computers but as soon as I get into contact with circuits and means to make a computer sense the "real world", I thought about giving it the opportunity to drive around next to other actions. In fact I´m trying my best to deal with microcontrollers and learn by doing.

Cheap yet relative accurate signal sensors

Thanks for visiting the nuthouse!
Anyhow, I'm trying to figure out a relatively cheap, yet accurate, distance-sensative sensor.

So, the end question is, does anyone know of a sensor type that can be mounted on an arm,
that moves from 0 degrees to 180, 6 inches apart, to detect my location by something I'm carrying?

-From what I've read, the standard RFID chips don't usually even cover 5 feet.
-I've tried bluetooth, but the sensor strength fluctuates too much for a clear reading,

Picaxe bldc ESC Driver

Hello guys!

I'm brand new to letsmakerobots and newbie of picaxe world...so forgive me for the noob question.

How to send serial data after collecting data from different functions


I need some help regarding my subject. My hardware is Arduino UNO. My setup is as follows.

I have 3 or 4 functions which collect GPS, compass and sensor data's. As telemetry i out put the data via xbee module wirlessly to my PC. My issue is when the data comes so fields missing due to delays on some operations. Example format of the data is lat,lon,heading,temperature,rpm. which is output from a serial.print

But when sometime due to some processes the some data misses. so tell me a way which i can do this much affectively.

Connecting two arduinos wirelessly

I've one arduino due and a uno. I want to connect them wirelessly i;m thinking of using bluetooth as it is cheap. I want to know is it possible using bluetooth and which bluetooth module should i use. If there is other cheaper or easier way to do the above mentioned task please let me know. thank you guys 

Source code for Srf05 and picaxe 28x1

is this the correct way to adapt the source code of fritsl's "how to make yfr" for a srf05 sensor? ... i suppose not -_- .. T_T .. can you help me fritsl? :p 




hacking the digital Sharp IR sensor

Check out this link, Ladyada bought a digital IR sensor by accident, and found a way to turn it into a analog one. Clever!

And an interesting aspect is that the D version is often cheaper than the A versions.



Make robots talk.. to each other.. dirt cheap!

UPDATE: More info on the subject here: http://letsmakerobots.com/node/5194

Original post:


I have this thing in the back of my mind that "the next step" for me must be my robots talking to each other.

LM324 question...

So, playing with oddbots distance sensor, the subject of using an op-amp to beef-up the signal was raised... I got a lm324 and did a little looking over the data sheets and quickly found there are about 4000 different applications for this little guy. Does anyone want to suggest a schematic that would be best to amp-up a signal coming from a IR photo-transistor?

Arduino Motor Control Code Help

I am currently using a arduino duemilanove, and it is awesome. I have been playing around with it for a couple of days now, and I really like it. Anyways I figured it was time to start to building a robot. I decided to start with the motors. For the motor control I decided to use guibot's tutorial. It worked fine, but the motors only traveled in one direction. Because I wanted the motors to also travel in reverse too I decided to experiment with my own code (on only one motor) that looks something like this:

Idea for Challenge? (Much needed!) (saving the fishies!)

I don't know what gave me the idea.. lol, I remember watching a video about this a while back.. but just remembered it today out of the blue.


Basically, it'd need to be small scaled for now, but maybe ideas for the future companies! (and/or countries!) But I can't believe it's seriously gotten to this point... a garbage patch bigger than the size of Texas, in the Pacific Ocean! They find fish and birds as well, their stomaches full of the plastic they ate. (I mean, FULL.. it's more plastic than meat inside of the fish!) But anyways..onto the "Idea":

Shooting mosquitoes with lasers

Straight out from Shoutbox I just snatched this:

gimmelotsarobots: On the bright side, mosquitos are now being killed by self guiding lasers. http://intellectualventureslab.com/?page_id=563

Searhced around, and found this cool video of death!