Let's Make Robots!

Automatic plant watering system with picaxe

I designing a automatic plant watering system

.A probe is placed in grow bag.It finds the resistance

If the resistance high ( >200 with 1 k conected ) then high 0 and a relay works

It works resistance up to 100 ohm then stops


Adding mini dissipators will improve motor driver performance or life?

I got these cheap motor drivers and they work fine, but get really hot fast, as soon as the wheel is stalled by something.
They are rated for 800mA of current for motor, 2.5v to 9v, but i wonder if adding some small dissipators can help handling more current or improve their efficiency.

T'rex motor controller HELP!!!!

Please help!!!!

My team and I are using the T'rex chassis and motor controller from Dagu. We would like to have the Arduino Due control the motor controller through I2C. However, we have been having problems. If we load the code provided from Dagu for I2C it works for an Arduino Mega but no joy on the Arduino Due. We know there are differences but have been unable to figure out what they are (libaries, pins, etc). I was able to modify the code and it now compiles and loads on the Due, but I am now receiving the following error:

Master Command Data Packet Sent

Buck/boost module for voltage, anything to boost current? charge pump circuit?

Hi There,

I was wondering how charge pump circuits and buck/boost modules work.  I have a buck/boost module i purchased on ebay, and by hooking up a multimeter to the output, I can verify that from 5V in, i can get get more than 5V out.

Does this mean that i can hook up a solar cell to the input, boost it to 30V, and power a lawnmower?  I'm guessing not because even though it is providing a higher voltage, its not boosting current.

So that leads me to wondering if there are similar devices to boost current.  Perhaps something like a step-up transformer?

Tutorials for kids to use Makeblock Robot Starter Kit -

I recently purchased the Makeblock Robot Starter Kit (bluetooth version). 

 was looking for a project to work on with my 8 year old son since he expressed an interest in robotics.

Is anyone aware of a tutorial that can teach an adult and child who are at the beginner stage how to make the Makeblock Robot starter kit work?

I have seen the the tutorials on how to assemble the robot (tracked and wheeled), but none on how to or what software to install on an iPad/iPhone, how to make them connect, troubleshooting and how to run the robots. 

How to build a delta 3d printer?

Dear: LMR

Hello LMR it is me Noah again. You should know for the past few weeks I have been trying to make a 3d printer. I have given up on my original designs. You see I had an idea for a 3d printer that was too diffucult for me to build which was a soft robot arm 3d printer but it was a failure. Now I have decided to build a delta 3d printer and this is what I am trying to ask you.

PayPal problems

Hello everyone,

I had seen some really cool stuff on ebay.com and had decided to purchase it later.

As nearly all the sellers take payments from PayPal, it was the only option to go with.

When i tried to add money in my PayPal account, I came to know that i counld'nt add money in it with my debit card.I don't have a credit card too.What's more ,it asks to link a bank account which my parents find too risky and do not help in it.

Is an Arduino Capable of Reading All Four Rover 5 Quadrature Encoders?

Note: Sorry this post is so long. I used bold text to indicate the main point of the post.

I didn't want to hijack Oddbot's Rover 5 threadso I'm starting this one here in the forum.

In replying to odong's question about the quadrature encoders I stated (among other things):

Build 18 DOF Robot Black Spider Robot

We had built this Spider robot with 18 pcs servo motors and it can "dance "  
and finish push-up under the control of the Servo Motor Controller Robot Contorller.
Here is the video which is full of fun. Listen to the background music.

How to properly secure aluminium servo horns to Towerpro servos?

Last night I finally put my Chinese bought biped together. Quite an exercise in frustration really, virtually every darn bracket had to be bend to fit. In hindsight I'd better made the brackets myself!


Anyway, the kit came with aluminium servo horns that are slightly too big for my Towerpro 996 servos. (It takes talent, I guess, to make things exactly so that the don't fit perfectly.) The result is of course that I have unacceptable play on the horn, weren't those aluminium horns suppose to be more durable and accurate than the plastic ones?