Let's Make Robots!


Looking for ideas on a I2C Pan/tilt stand-alone sonar

This quest to build a stand-alone I2C pan/tilt range finder controller started with an article here by Ladvien.  In    http://letsmakerobots.com/node/39130, Ladvien explores using an ATtiny85 (84) as an I2C motor controller...

And in http://letsmakerobots.com/node/39222,   Chris the Carpenter   gives us an awesome pan and tilt code example... so...

PICAXE28x1, Sharp IR Sensor and Infrared sensor problems

Hi everyone,


I'm making a robot project for my mechatronics course and I am using picaxe28x1 with an infrared range sensor that I just copied from the Start Here post here at LMR. I did everything, and exactly the same set up like what the guy did. Howeve because we are required to make at least one of our own infrared circuit, I added an infrared sensor (with a transmitter and receiver circuit and a LED indicator) circuit together with the servo and the Sharp IR sensor. I did the set up and wrote my program but it's not doing the job.

So this guy happened last night. I have been inspired by the work of Mr. Protowrxs and his Box Head Robot and thought I needed a little deskbot as well. I also … Read more

Help requested with programming "Official Arduino Robot".

I need some help programming a servo routine for the new "Official Arduino Robot".

So far, NONE of the standard Arduino servo routines function with this robot. "#include <Servo.h>" is the most common servo control routine and I get an "Error 17" whenever I attempt to use it.

More recent "standard" servo routines refuse to function as well.

It was a big shock that the robot included no servo control in its list of functions. "Forget something, Arduino???" :-)

Any help would be GREATLY appreciated!

PROJECT CONTINUED! So I found a motor from a toy. Works fine. The same speed as the other. But I still have the problem with the whole robot turning. I'll post a … Read more

6 wire RC steering servo?

Hi All!

This is my first post so go easy on me. :)

I am trying to build an obstical avoidance robot and decide to salvage a chasis from an old Radio Shack RC truck. The main board is fried. when I got to the se=teering mechanism I discovered 6 wires coming form what I would think is a servo. I was expecting three wires so I'm not sure how to hook it up to my motor shield for an arduino.

I discovered that if I applied a voltage to two of the wires the wheels turn on direction and if I reverse them they go the other way.

My PCB's Are Here!!!

Hello everyone my PCB's are here, they were actually meant to make my robot more tidy as shown here (turn off the sound)

Is my servo defect? (fast one way, struggle the other)

I bought a pan/tilt kit from nodna.de, with 2 micro servos...
I hooked them up to my Fez Panda II's PWM and 5V power, then made a simple program to move them  from all the way left to right.

But when i run it, it moves really fast to one side, then it struggles to move the other way, nearly dont move...?
Same problem with both of them... sounds like they dont have the power to turn... ?

Could there be somthing im doing wrong? or are they just simply defect? 


Using Sabertooth 2x12 with motor and servo.


I have an RC car that i've stripped down to it's bare essentials.  It has one motor that provides forward/backward movement and it has a servo that turns the front wheels left/right.   I can use the Sabertooth 2x12 fine with the motor.  The problem is however the servo. 

Now available from PicoKit!http://www.picokit.com - A cheap and simple 3 servo robot walker that anyone can make for under $40. My students in Industrial … Read more

Everything you never wanted to know about two wheel drive.

Platform Drive Control.

This platform is driven by two wheels mounted so that the wheel axis
is just off center. There is a small caster wheel mounted in the 'rear'.

At this time there is no speed control feedback.

Maneuvers are accomplished by independent but coordinated control of
each wheel motor.

The drive motors are servos that have been hacked to continuous rotation.
The servo hack involved pulling the feedback control board and pot as
well as cutting the stop on the main gear. Thus the servos are converted

Need help controlling Traxxas ESC and Servo with Arduino

I'm working on an autonomous ground vehicle, guided by a U-BLOX Neo 6m GPS Module, and HMC5883l compass.

The ESC connects to the 7.2 NiMH Battery pack and is supposed to be connected to a RC receiver with a standard 3 wire servo cable, it also provides 6 volt regulated power from the same cable. Because the power is too high for an Arduino, I used a separate 5 volt power supply for the rest of the electronics, except the steering servo. Using a separate power supply makes the ESC and servo uncontrollable, creating a lot of jitter.

Potential Parts Store


I am looking into selling robot parts online, and I am curious what parts you, the potential customers, would like to see.

ATtiny servo control


After a brief discussion with fellow LMR member Maxhirez, about his Hedwig robot,
it seems as though there isn't much support for servos in the ATtiny family of
microcontrollers. After fighting with the 8-bit servo library I found HERE that was
supposed to make it as easy as a standard Arduino to add servos to an ATTiny project,

how to get wheel velocity

Hi guys,

I am taking "control of mobile robots" course on coursera and is pretty intrigued in building a 2 wheel robot car. One of the issues was the control of the 2 wheel velocities here.

So far, I've got a Uno and bought the magician chassis from sparkfun. It provides 2 dc motors. May I know using the dc motors, is it sufficient to be able to know and  control the individual wheel velocities? 

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

Servo Standards?

Hey all,

Just graduated from college and started a new job. I finally have time to pursue projects I've always wanted to do.

ANYWHO. I bought a cheap aluminum hexapod frame from the internet that recommended I use Tower Pro MG995 servos. Unfortunately I just found out through online reviews that these servos and their improved models are not so hot, to put it extremely lightly.

I noticed however that a Futuba S3003 I had lying around seems to have a casing with mounting holes that fit flush with the holes in the frame as well.

Moves a vehicle forward, back, left, and right; teaches about gimbals
All my projects & progress are available at marginallyclever.com. about They were first researched in 1938. Curtis Boirum built one that got on Hackaday. Now … Read more

what battery would you recommend for powering 10 servos at 6v ?

I am currently working on a humanoid robot and am trying to ruduce the weight and increase the opperateing time I am useing 4 AA batterys to power the top half 12  servos and another 4AA batterys to power the bottom half 10 servos  22 servos in total . The AA batterys tend to go flat quite quickly and haveing 8 AA batterys make the robot heavyer also if i could recharge the battery it would be a great help. the servos are rated at 6v maximum and 4.5v minium what would you recommend ?

Any help is greatly appreciated.  

Servomotor torque requirement for a quadruped robot


I'm planning to build a quadruped robot soon. My design is very similar to the design in the following link.


I'm not that good at mechanics. I like to calulate the torque required for each motor. Is it ok to use the formulas/procedure in the following link to design a quadruped shown in the above link?


Servo Guts Connected to Another Motor

I just got a Rover 5 chassis and I was trying to figure out an easy way to control the motors. Would it work to take the electronics from a servo, disconnect the original motor and solder it to the Rover 5 motor?

Navigate around via ultrasound
Using a
This is my very first project using an Arduino Uno. It uses 2 Futaba S3003 servos that i have modified for continuous rotation and one regular one to move his … Read more

Number of Servo's Attached to an Arduino.

Just a quick question that I'm struggling to get a straight answer from the intertubes about...

I'm looking at purchasing an arduino board to control some servo's, and wondering how many each can control?

For example: Uno R3 has 14 digital i/o pins (6PWM outputs), and 6 analog inputs. What does this mean exactly?


I tried to write a code but the servo would not stay so

Please can someone write a c++ code for arduio for me

How to contol servo speed from serial

Hello all

I have  renbotics ServoShield and I have made a code on arduino where from serialport I can send commads to servos and it happens with that way... S01P1200,S14P2300etc..I mean that  Servo 1 to 1200 posion and servo 14 to 2300 posion

Wire and Servo Connectors


I am currently am ordering parts for robot #2.  As robot #1 is a nest of wiring, this time I want to use cables that have 2 or 3 conductors and use the connectors normally used on servos.

This has leads to two questions which are:

Is there some reason to choose "twisted" wires (2 or 3 wires wrapped around each other) over flat ribbons (2 or 3 wires side by side)?

Walks around, soon avoids objects
Using a
Inspired by some other 4 servo bipeds on LMR I decided to make my own. I had to name it Bonnie, because my other walking robot was named Clyde. Bonnie was just … Read more

PICAXE 28X1, debug command and servo twitch


I came across something interesting, I thought I would mention.  I had my robot plugged into my computer and was working on the IR range sensor.  This meant I was reading the ADC pin and had a DEBUG command in the code to show me the values I was getting back.

While this was going on, one of the robots arm was ...twitching... a bit, like the robot had suddenly developed Parkinson's disease.

While trying to figure out why that was happening I removed the DEBUG command statement and the problem disappeared.

UPDATE : October 23, 2012 Apparently some guys got trouble opening the CorelDraw files attached before. So I exported those files into various extension : cmx (to … Read more