Let's Make Robots!


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Program freezing (or getting stuck?) when asked to calculate large numbers

Hi Guys! Ive done buckets of trouble shooting on this, and i THINK i have identified where the problem is, but i cannt work out how to correct it. In short i am programming my CNC router (converting GCode into CNC movements)

Record PWM values over time, tweak graph, playback to robot possible?

Hi All,

I'm trying to find the best way for me to drive an RC car around, have either the transmitter or car send the PWM values its using back to a computer which will record it over time.  I then want to tweak the graph, and then play it back, and have the computer send the RC car the new "tweaked" PWM data and it will then drive around by itself.

Charging LiPo Batteries


I have a Turnigy 2 Cell 7.4v 2200mAh battery and iMax B6AC Balance Charger.

using Multimeter as current sensor - can it output to Arduino?

Hi All,

I'm in need of a current sensor, but don't want to wait 40 days to get it shipped from China, or want to pay over 10 times as much buying it locally.

I have an old cheapo multimeter lying around, and I just opened it to see if it had a current sensor IC in it.  It didn't, and now that i've put it back together, the conductive rubbery strips that press against the LCD are misaligned and the display shows me gibberish.

how do I find the time....

Hello fellow robot makers,

This may sound familiar for some and for others maybe a stupid question, but how do you guys find the time to practice your hobby.

expandable processor

Which processor board is easily expandable? What if you suddenly end up needing more inputs/outputs

I'm afraid that when I create my robot project, I will eventualy end up using all the inputs and outputs and will need to change the processor board.

looking for ideas how to attach third wheel

Hey guys I am slowly buildibg my bot this one will stand

roughly 4 feet high. Before I jump right in and start making

any cuts or add ons I was lookibg for ideas

what to use and suggestions on place ment.

I do have two more wheels of same size as the ones currently on the motors in the pic. Plus one smaller one. I 

am looking for the castor wheel type but as of now dont have a big enough one.



Choose a motor stepper driver for Nema 17

I have 2 stepper motors Nema 17  (model and data sheet : https://s3-ap-southeast-1.amazonaws.com/...20RevA.pdf).

Do you know a good cheap driver for this motor?

I tried with pololu A4988 driver, but I don't like it. It doesn't have enough Output Current and I broke it.  


Stencil for Fun Light Switch Box

I just received a Fun Light Switch Box kit from Jameco.  The instructions call for a stencil to be found at http://letsmakerobots.com/files/userpics/u5293/Fun Light Switch Box Stencil.pdf. A request for that site yields a Requested Page Not Found window.  How can I find this stencil, which is essential for my putting this kit together?

T'Rex Robot Controller Board Discontinued ???


Has the T'Rex Robot Controller board been discontinued?

I can't seem to find it in stock anywhere. All the sites I've checked has it listed as "Unavailable, Unknown Restock Date".

If so, why has it been discontinued?

And is there another board that is coming out to replace it?

full sized robot guidance

hey guys 

I just finished salvaging a power wheels kids three wbeeler

I plan on upsizing my avoidance robot

to this frame and do what needs to be done

with motors.

I have a question and I am confused

This toy has only one motor and a gearbox i supise

How do I go about using this or can I

I am wondering how this works


Switching to Arduino

I was a basic stamp2 guy, I planned on using the Propeller for my next big robot, but instead of learning spin, I might as well learn whatever arduino uses, besides Arduinos have ADC's which I need and are fully compatible with Pixy, which I already bought. Question, what's the best (or really good) arduino for Phydo: http://letsmakerobots.com/robot/project/phydo-0 (Large, at least 6 servos, plus dc motors, at least 8 adc, tons of I/O, voice, speech, vision, etc) I was thinking Mega 2560 R3, (but not if it's going to be obsolete next month which usually happens to me) Should

3D model of psuedoscorpion

I am looking for a 3D printable pasuedoscorpion for my son. Any help and or hints will be appreciated.

Motee - the tiniest & smartest motor controller in the World


I’m Karol Karczewski, the team leader of Lime Devices group. 
I’m happy to annouce that we have just launched our first campaign on Indiegogo:
The motor controller dedicated for robotics named Motee.

Web Control of Robot (RPi / Arduino) - Software Recomendations


I am enhancing my Arduino Nano based autonomous collision avoidance robot by adding a Raspberry Pi to stream video to a web page and provide manual control of the robot via buttons on the web page with the video stream.

So far I have installed Apache2 weberver and created a web page using Bootstrap with a button on it, I have successfuly connected the Arduino to the Pi via I2C and using a CGI Python script I can press a button on the web page to turn on an LED. 

NASA SpaceX Launch Invitation

Hello LMR,

As some of you might remember, we were recently awarded a small piece in the NASA SpaceApps Challenge.As a small gesture of giving something back to this amazing community, I'd like to invite a fellow LMRian(s) to  join me and a couple of my friends at the NASA SpaceX Launch at the Kennedy Space Center this September. It would be a pleasure meeting you in person.

walking gaits.

I've been building the body of a poppy 3d printed robot to use as my biped Plat form but I'm having trouble grasping the equations for dynamic motion. Essentially I understand it to be a 2 in part; a double pendulum connected at a single point with control using a single inverted pendulum model, then switches over to the other leg and continues the set up. Granted I need to do a lot more programming tutorials to further my understanding but I know I'm going to need a ton of help. Would placing an accellerometer/gyroscope in each foot and one in the head make the system compute better.

Quadrature Decoders

There has been quite a lot of discussion regarding Quadrature Encoders and Arduino. I have typically used Microchip PIC24 with embedded hardware or added external circuity to off load the cpu. I do want to have example code for class.

Autonomous Solar Panel Spider Project (Arduino)

Hello fellow robot enthusiasts/experts,

My name is Michele (Michael) and I'm from Italy. I really appreciate all your efforts and creativity for the love of robotics! It's truly amazing to see all your projects.

diy shoulder axle/pin/shaft/dowel pin?


I would like to 

- create a shouldered pin* in order to glue gearwheels** to it 

- ask you for any advice or link that may hint me towards a solution


any ideas are highly appreciated: