Let's Make Robots!

New Bevel Gears from ServoCity

Now you can build right angle drives inside or outside of channel with these new 24 tooth, 32 pitch bevel gears. We offer them in four bore sizes, 1/4”, 4mm, 5mm and 6mm. Great for building differentials or any application where you need to transfer rotational motion 90 degrees. Sold individually with set-screw.

What is your favorite dual H-bridge motor driver?

I am looking to find out what motor drivers people like, so that I can try them with my RoboPi controller.

So far, I have tried driver boards based on:

- L9110S

- L293D

- L298N

- a Cytron 15A/channel discrete MOSFET board

I have, but have not tried yet

- Dagu "Mr. Basic" driver board

- Dagu 4 channel board for the Rover 5

- OEM 320A (I have serious doubts about the rating) driver

Which boards do y'all like, and why? Please give amp rating and price if possible, and links would be great too :)

Mapping a range of numbers to another range of numbers ....

Hi all ... had to convert a range of numbers in my online course to another range of numbers using C code ... 

in Arduino this is easy using the Map function ... but i had a lot of problems trying to figure out to do it in C and after googling online and not finding anything of use decided id have to try harder doing it myself so got out the excel sheet and tryed working it out myself ... and after getting it sorted decided to do a little write up on it .... 

Best way to drive two motors

My goals are to (1) move the plunger of a 1ml syringe for about 0.5cm in a second then move it all the way back; and (2) move another plunger of another 1ml syringe for about 1.5cm in a second then move it all the way back. The movements of syringes are coordinated but not necessary in unison, meaning one might lag behind another.

Bluetooth controlled projects - Android/iPhone apps

Hi everyone


I'm coming to the end of a project; a Wall-e Robot, with Arduino internals, controlled by Bluetooth via an attached module.

I have made a simple python app and also found a few android apps that do a job;

The controllers send a single character to the Arduino (F, B, L, R etc) and the Arduino triggers the correct motion.


I am stumped looking for an iPhone app to allow me to do the same, however - has anyone ever found such an app?

Robot Talk Show 'Babbling Bots'


UPDATE 20/5/2014

The show was succesfully livestreamed and can now be watched by those who missed it here.

Thanks to all the LMR folk that came along! They've told me it was good and I thought it went good so I'm happy.

How to program a maze bot in PICAXE for 18M2 Kilroy? (Urgent)

Hi, I'm Eleni, a high school student :) In my technology class, we are required to participate in a robotics competition in three catergories, two of which I am already sufficient in, but the third...not so much. I'm not very savvy at coding (PICAXE), and my robot is 5.25x7.25 inches, and we're only allowed to use touch sensors to help it get through the "maze" (the set-up is an attachment). I understand the basics of coding, but I'm pretty lost...I would greatly appreciate some help, as it's due tomorrow. Thanks! :D

Robot Competition

I am beginner to robotics.  I just wanted to know if there are any local robotic competions that I can attend.  Right now, I am only a freshman in High School.  Also, I live in the New York area.

looking for a motherboard...

Hey guys,

   I am looking for a motherboard in order to assemble a high performance computer for my robot. It should support: A 2GHz quadcore cpu or better in order to support the vision system, (optional)a nividia graphic card for cuda application.

   I was thinking to assemble a pc but battery is another concern--I can't find a battery on the market to power such a high performance pc. 

RoboPi - the most powerful Robot controller for the Raspberry Pi (adds 8 core co-processor)

RoboPi stacked on a Raspberry Pi

Mikronauts RoboPi adds an eight-core 32-bit microcontroller running at 100Mhz to the Raspberry Pi in order to off-load hard real time I/O and allow more precise timing than Linux running on the Pi allows.

RoboPi Features

confusion over what voltage/amp is needed to power a wifi camera...


i have this wifi camera: http://foscam.us/products/foscam-fi9821w-megapixel-wireless-ip-camera.html

I would have liked to have powered it either through the 5v output of raspberry, but i quickly learned that that would not work.

Now the specs aren't clear on the voltage or amps that it draws..but the dc adapter that it came with outputs 5v/2amps, so i figured at minimum i needed a power supply that does the same.

Battery packs and power distribution

Before I ever started with robotics, I read Gordom Mccombs' book Robot Bonanza.  He said it's best to use two battery packs, one for the drive motors and one for the microprocessor .  And I built all of my robots like that.  But I'm wondering if that's what everybody else does?

Simplest electronic randomizer

I am trying to get some random element in the output of my latest solar powered bot. What I would like to be able to do is to have the bursts of activity from the solar engine make the motor turn one way or the other randomly. 

I tried creating a little circuit that had a comparator linked to two photosensors set close to each other so that it was mostly random what the output was but it got a little complicated and I figure that there must be a much simpler way to do that.

Motor Arm Length Calculator

Below is a picture of what I'm trying to build. This is the motor that I'm using, which has plenty of torque.

How to send Lego PF IR signal to PF receiver from PC?

I have a Lego RCX IR tower (http://www.robotika.sk/mains.php?page=/projects/robsapien/irtower.php), it can be used to communicate with RCX by LNP protocol (same as brickOS protocol http://lnphost.sourceforge.net/brickos.html).

Now I want to know if I can use this IR tower to send LEGO PF IR protocol to PF receiver? You can find PF IR protocol hear (http://www.philohome.com/pf/LEGO_Power_Functions_RC_v120.pdf).

I tried to use SetCommBreak, ClearCommBreak and nanosleep to create mark, pause, start, stop, high and low, is this possible?

trouble with a button

Hi guys, as some of you know I am trying to learn some arduino, exspand my stuffs so to speak, what I want to do is push a button and do a RGB led routine, push button again and turn it of, hoff's bling thing medalion got me thinking on this. I'm using Ladvian's excellent Attiny board an 85 breakout board. The idea for me is if I can figure it out I can turn most anything on or off with it, but also run a routine, or program. here's what I got so far bdk6 and JerZ hinted at the problem, but its beyond me.

20% OFF And Free Gift for ICStation 1st Anniversary Celebration

ICStation welcomes the first anniversary now.

To express our gratitude on your support, we are offering 20% off on all items and free gift from 20th to 31st, May.


Draw Images to ILI9340C Adafruit display via serial

It will take around 1 minute 20 seconds to draw an image to the display at a resolution of 320x240 because of SPI Data Rate

I've implimented some basic encoding Int to Hex and back again via the microcontroller which will speed things up a very tiny bit but it helps :)

translate or change the code

I need an expert in C/C++ programming to help me translate a fairly complex piece of C code  following line robot into matlab code. the C code is from webots software. The original author of the code can't do it, but we have his permission to do it.


Please reply here or PM me if you're interested. Thanks. 

Crazy problem with uint16_t colors

I'm trying to print a specific color to a specific X,Y position to a tft display however i'm running into trouble
I can't seem to convert the incomming hex values to the propper color codes

//Input String Format: XXXYYYFFFF - Data comes through as 010020FFFF as the display only has 320*240 resolution

    //Input String Format: XXXYYYFFFF
    String xA = inputString.substring(0,3);
    String xB = inputString.substring(3,6);
    String xC = inputString.substring(6,10);