Let's Make Robots!

MP3 shield for Arduino NANO

I got this MP3 shield recently and tried it for 2 days. Things are a little bit funny and strange. When I upload the sample program follow by few instructions, most of time they are not working. But if I keep clicking RESET button on NANO once in few seconds it works after 3~5 clicks.

Arduino NANO v3 heat up with shields

I don't know it just me or everybody else too. Have you ever experience your Arduino NANO on any shield and plug USB to upload the program and NANO become very HOT? NANO works fine without shield connected.

The only shield works with no heat up issue is the undershield from Rocket brand studios. (Great job! Chris.)

and are all having heat up problem.

Merge power wire on Servos?

I am making a small hexapod. 18 servos needs a lot of room for those wires. In order to save some room I decide to cut wires and make it short. Before do that I got a question. Is it OK if I merge 3~6 servos wires together and only keep signal wire individually?

For example, Can I group 2 front legs, knees and hips voltage wire as one wire and Ground as another one set, then only keep 6 signal wires by themselves. So, I only have 8 wires from servos to controller board for 2 legs.

Serial print the String in Arduino

Hi Guys,

Maybe this is a very basic question, but I tried it and work around it with no luck. Hope anyone can show me any tips for STRING in Arduino. I use it for multiple servos. Following code works fine:

This is pretty cool!! quadrotors in formation

Check this out. Looks like UFOs.


Look at the speed and reaction. That's kinda..........fast!
(Did you FASTFORWARD the video?!)

How do you determine pins on relay?

I got this relay today but not sure how this relay works. Try to search on this particular relay but not much information or datasheet. I tried to wire it around and find out if I connect A and B with battery I can hear the TIC sound so I assume C1,C2 will be connected or C2 and D2, however it doesn't work that way. If I connect the battery on C1 and D1 and connect a motor on C2 and D2 the motor will work. So, I guess C1 and C2 is linked and so as D1 and D2.

BRAKE wire on a motor controller

Recenter I got one of this motor controller. The yellow and black wires are for BRAKE as they described. How doe s this BRAKE wires work? Should I connect yellow to one of digital pin and black goes to Ground? anyone knows what's the function of this wire?

I am guess if signal "1" send to yellow the motor stop even throttle is full? and signal "0" to release it? or I am totally wrong here?

Adjustment for potentiometer via Arduino


Hi Guys,

I have bought a joystick as picture above. I tried to connect the potentiometer(the one on stick) to arduino by using following sample code: