Let's Make Robots!


Biped Howto: Moving servos

+++ UPDATE (12-march-2014): Rename title as "Biped Howto".

Hi, I will try to explain, in a very simplistic manner, the way in which servo motors can be controlled.

Servo motors are controlled by a PWM signal, in which the active part of the signal (known as duty cycle) define the amount of degrees the servo will rotate.

Attiny 2313/4313 servo driver

Hello everyone!

Attiny85/45s are great for small projects because nearly all pins can be used to drive servos simultaneously.

However 5 servos are nice but not enough. I found out that I have bought some Attiny4313s a while ago. They 20-pin chips that can be programmed via arduino. Now I am wondering how many servos it can control. There already are different approaches:


Microscope Camera Driver

I recently purchased a microscope to help with soldering. As a gift I was given this camera for the microscope but no software. Does anyone know where I can find drivers for this camera?

Provides better performance than normal drivers
I am participating in Google Science Fair 2013. So, I thought of sharing my idea. A simple idea. I have modified loudspeaker drivers in two ways. The benefit of … Read more
all in one robot control board
This project aims to create an all-in-one robot control board. Unlike the arduino platforms, this board will contain servo drivers, motor drivers, accelerometer, … Read more

Driving a ride on toy car motor

Hi folks,

As part of a project I'm building I need to create a rotating platform and I recently salvaged a DC motor and its gear train from a ride on toy car, so I thought if it can scoot a child around it should have enough torque for this application. The problem is that I'm not sure how to drive it.

sn754410ne dual motor driver not working on one side (one motor)

Thanks to @JAX, it's fixed. it was related to the push button. wires maybe broken or something, going to test further. But push button  2 works for both sides of the driver so it was indeed push button 1 that did not work.



A stepper motor driver where a dsPIC33 both monitors the current and controls the PWM via an L298N.
A few years ago I started building stepper motor drivers.  First it was a simple unipolar driver.  My motors wouldn't rotate faster than 1 to 2 rps.  So I … Read more

Flyback Transformer Driver

I took a flyback transformer from a crt monitor and built the driver here - http://tacashi.tripod.com/elctrncs/555sstc/555sstc.htm

Picaxe USB driver issue

I have just received my Picaxe 28X1 Starter Pack and, after an hour of trying, am still unable to install a driver for it. I am running Windows 7 Ultimate, 64 bit on an AMD Phenom II X6 1035T at 2.6 GHz (or so they say). I have tried the self-extracting, self identifying driver, I have tried the manual install. I am not getting anywhere... well, nowhere good. I have combed the rev-ed site. I assume that the driver was included on the CD I got with the starter. It seems likely that I am just missing something obvious.

Any advice will be appreciated. Thanks!  ~Allen

Pololu RP5 motor

Hi there, I have recently bought a RP5 chassis from pololu, this chassis is holding 2 brushed DC motors (6V) and I have some questions: first of all; how can I control it? I mean, do i need to control it by PWM or is just 5v or 0v?

second, I built a little pcb with a L293D to protect the controller (Arduino) from reverse current, is this ok? 

SD 20 servo driver

Hi guys, Recently I posted a post on the forum about controlling a larger amount of servos (18). A few people suggested the SD20 servo driver chip which looked awesome so I went ahead and purchased a few of these chips. I have made the board and setup my picaxe 40x2 to send out the commands via i2c however I have ran into some problems that I just can't work out. All of the servos do seem to move to the given position but they seem to lack greatly in power. Second problem is that the servo movement range is greatly decreased.

H546 Unipolar Stepper motor driver

Hi, ive been trying to make a steppermotor driver for 2 http://www.active-robots.com/products/motorsandwheels/stepper-motors/datasheets/103h546-0440.pdf

I have used a ULN2003 like this:

(the second motor is in 5, 6, 7, 8 (I have a bigger ic)

L293D Motor Driver

Hey, can anyone tell me if the L293D motor driver chip can take an analog value to its input pins?

Or does it have to be a logical 1 or 0?

Just wondering if I can drive my motor at variable speeds with it, or if I only get one speed or no speed.

Here is a diagram of the chip:


Hi everyone, This is my most recent project. It is a robot which uses two cheap drills’ motors, that I bought a while ago for my tank. I didn’t like using … Read more

Alternate 3 pin dual motor drive?

I know enough to be dangerous to components.

I had thought about using 2 4427 MOSFET drivers and tying one input from each driver together to a single uC pin. I could then control fwd/rev with two digital pins and put a pwm signal on the shared pin. The 4427 data sheet says the input current is 10uA per pin and PIC pins are supposed to be able to source 25mA max. Is there a flaw in my thinking?

As far as a schematic, I imagine many of you have seen what David Cook has posted on his RobotRoom site.

Schottky diode bridge IC for L298N?

Hi all!

Noob question: I'm using the L298N dual full H-bridge to drive my robot's 4 motors, can someone please give me the name of a chip that contains schottky diodes in a bridge configuration, so I can use it on the outputs to block back EMF? Sparkfun does the same on their boards: http://www.sparkfun.com/datasheets/Robotics/ROB-09571-Serial%20Controlled%20Dual%20Motor%20Driver%20-%20v11.pdf

I know that there are such ICs since I recall a friend using a 16-pin DIP in a similar occasion, but I can't remember it's name. I think it started with "L".

Mini Sumo Bot Parts!


I decided to make a mini sumo robot a few weeks ago instead of doing an obstacle avoider. Turns out that once you think about it, mini sumo bots and obstacle avoiders are pretty much the same! The only changes I would need to make would be to the code. Great! Sumos can also double as line followers. So in short, they're pretty versatile. Here is an image of most of the parts that will go into this sucker. 


H-Bridge Motor Driver 1A

the store that im buying all my gear for the start here robot doesnt stock the l293d motor driver

they do, however have the H-Bridge Motor Driver 1A which, in the description, is said to be a replacement for the L293D

is that true??? should i buy it or just go to another store to pick it up?

thanks muchly...

sliding parking of a robot car

A pair of picaxes, a pair of sensors and...

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.

20Amp Motor Driver/Controller

I am looking for a 20 amp motor controller/driver. I prefer an IC, that way I can integrate my own driver circuitry, but if it is cheap (under 50) post it. I'd prefer if it could provide 20 amps per channel. It will be operating on 12VDC.

RepRap Conversion for a set of Probotix SideStep Stepper Motor Drivers


An Arduino or similar microcontroller shall be used to create a RepRap-style front-end for the HobbyCNC EZ Driver board or similar DB-25 controlled stepper driver.  This front-end microcontroller application would allow RepRap applications to control a number of powerful CNC machines.


Help with H-Bridge

 Hello, I need some help to reduce the chances of burning my precious Arduino/apartment.
I managed to build and test this H-bridge 

Motors and Arduino

   Hello, is it possible to control regular small DC motors with an arduino board? If yes what limitations do I have?  can I use the PWM feature to increase decrease their speed?+

what about servos, do I need a motor driver or can I control them with just an arduino? 


Drives 2 DC brushed motors. Holds 4A per motor.
Need a 8A  motor driver but don't have a lot of cash, look no further this article describes a simple and cheap solution. This project uses just few electronic … Read more