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4 Axis Robotic Arm

     I am a beginner in robotics and currently I am trying to build a 4 axis robotic arm with rotating base and I need Kinematics Equations for this project . Can anyone help me with this. 

2D model of my robotic arm is attached

running 6S battery at 2S, then switching to 6S via radio control?

Hi All,

I want to test out a brushless RC system within 2S safe parameters, and then go into the danger 6S zone for a few seconds, then go back to 2S.  I will of course be using ESCs and motors that can handle the momentary 6S burst.

My question is, via radio control, how would I be able to switch the RC robot from 2S, to 6S, then back to 2S?  I have a cheap surface RC gun style 3 channel transmitter and receiver.

The 3rd channel looks like a good candidate for on/off switching, but i'm not sure how to do the 2S/6S switching.

Raspberry pi 2 + T'Rex controller -> battery

hi, I need to know, how to supply raspberry pi 2 and T'Rex controller together. I have this battery (http://emotors.cz/pohonne/11445-giant-power-nimh-1600mah-72v-10-20c-.html) - 5000 mAh, 7.2 V, 10-20C.

I dont know how big voltage can I connect to raspberry. If I can connect in series or paralel rasp with T'Rex to battery or I need new battery for rasp.

PS. - if you have some good article about connecting raspberry pi 2 to T'Rex (arduino) through I2C, send me that please :)

thanks :)


Excuse me friends,last post was full of Eng-mistakes

and I didn't get the right answer though

here is what I want to ask:

I'm just migrating from AVR to ARM and I'm reading a book about ARM

but still reading the first parts and introducing

I wanna "run before I can walk" 

I want to do small projects with ARM and experience

more than 70 MHz clock speed beside reading that

book (which is in persian) - so :

My Question Is :

GEEETech i3 3d printer

Hi to al im new in this, my printer is setup and ready, but i'm trying to make a parts from a draw and i dont know how to do that,  im using repetier for printing, also i found freecad and Slic3r

i dont know how to transfer the draw to a object!


Need help!!


Wireless control-need help

I want to learn how to communicate wirelessly, particularly using WiFi. The aim is to achieve an automatic lighting system(inputs from sensors like ldr, motion sensor) and a robot(input from sensors like android phone's gyroscope). Please help me get through, first step will be to be able to use WiFi.

How to make a robot turn while going forwards

I have my robot http://letsmakerobots.com/start?destination=node%2F17 which i want to make turn while driving forwards, how do i do that?

Arduino Motor Control


I am working on a web controlled rover and need a little help with fine tuning the controls, I need more precise control over the motors.

Bottom Line Up Front (BLUF)

How can I get the Arduino to process a command for a given time period, I know how to invoke a delay between commands using time.sleep(Number of seconds) but not how to run a function for a given time. My guess is that it would be in a timed loop but I don't know how to do this.


My Father's Day gift

     Today is Father's Day here (in Brazil), and it's my first one.

     That's what I got from my son Martin and my wife!

Yahmez I hear you know someone, who knows someone.. Well I just have a question..

So I hear you have a good source for faulhaber motors, and I'd like to hear which kind of motors you're able to supply and the cost + shipping cost to Denmark.. 



Robo-War--A call for ideas

We are having a robot war in our engineering institute, IIT Guwahati.

Need some ideas....the task is to push the opponent out of arena or immobilise it for atlest 30 seconds. Current limit-10amps, Weight limit-60kgs.


ROBOCALYPSE: WRECK OR BREAK AIM: The  objective  is to  make  a  wired/wireless,  manually controlled  bot that  can immobilize  the  opponent’s bot in  a  one  on  one  competition.

World Maker Faire NY 2015!


September 28, 2015: Post Maker Faire Review

The Let's Make Robots Maker Faire Team

We had an amazing time at Maker Faire this year! I would like to start by thanking the whole crew.

Lawnmower Project - Drive Motor recommendations

Hi All,

First post here, such a great forum!

To get right to it, I am looking at building an RC lawn mower. At this stage the plan is to just start with a 4 or 6 wheeled frame. Each wheel will be driven directly by a motor. Basically its a big, hella strong rover! It needs to be at least 4x4 because I will be mowing on a slope (not up and down the slope, but along it so traction is vital).

Need experienced users of Pyose/NUKE editor for Hexapod

ive built a Hexapod using MG90S digital servos and a Torobot 32 channel servo controller but I'm having trouble learning the IK. I ran across a program called PyPose\Nuke editor.

The easiest way to program my bot using that controller would be to write each action group seperate and download it so it will give me a Function to program the PS2 controller it comes with to wirelessly control it.

Help sequencing a hexapod ripple gait.

Im looking to see if any body can help me design a hexapod ripple gait sequence for a serial servo sequencing program? Ive looked around and can find several move lists where it tells you which legs move and in what order but not what the othet legs are supposed to do at the same time.

I would like to start from the beginning. First leg if you please.

Any help would be appreciated.

Monster moto shield + Arduino +Pololu 12V, 29:1 Gear Motor Encoder hardware problem

electronic enthusiasts!

I am trying to build a balancing robot with two wheels, using the polulu gear motor as mentioned above. In order to have a strong motor driver,the monster moto shield is used in this project. Here is the components and datasheets which is used.


Li-poly RC Battery 2800mah 11.1V 35C.

Arduino saint smart

2x Pololu 12V, 29:1 Gear Motor w/Encoder 

Monster moto shield

Problem with PID controller


i'm making a line follower project and i was thinking to use PID controller, but i don't know how to calculate the kp,ki,kd ..!

and there's a little probleme, i don't know what's beter to use, digital or analog ir sensor in PIC16F877A ?

thanks .