Let's Make Robots!

Changing Polarities on DFRobot 2A Motorshield

How to change to polarties of the motor shield to change the direction of the shaft? DFRobot's 2A motor shield has only 1 IN ang 1 EN for each motor.

From what I've learned, to be able to switch directions, you need to change the polarities. Is there something I am missing?

Arduino Uno R3 Refusing Upload

After a very long absence, I have finally returned. I'll bet none of you even remember me!

Anyway, I got  a new Arduino Uno R3 yesterday in the mail. I installed Arduino Software 1.6.3 (latest stable release) and tried to upload the Example sketch, Blink.

It compiles fine and finds the board fine. But when it comes to uploading, it always get's stuck. It never gives me a message telling me the upload is completed. The progress bar always stops at about 80%. I have been letting it sit like that for about an hour now.

Any ideas?

Seckill Activity: ICStation Atmega328P UNO R3 Dev. Board $7.00

ICStation New Seckill Activity is ON now.

Can't upload a script to my Arduino mini

I just received my first Arduino. I hooked up a pro mini Atmega 328 to a breadboard along with a mini Usb adapter.

I read all the directions on the Arduino site on how to hook both of these up and followed the recipe HERE.

This is what it looks like.

First arduino setup

Laser wood cutting

I'm working on outfitting a shop in an RV. I've been told that the noise from things like a table saw might be enough to get me kicked out of an RV camp so I'm looking at alternative ways to cut wood. Right now I'm looking at cutting up to 3/4 inch plywood and 1" of hardwood.

Would an affordable laser cutter (say under $10,000) be able to cut these types of wood?

I need to be able to cut up to a sheet of 8' by 4' plywood or maybe up to 8' of normal wood.

Is this a doable thing? Is it quiet?

pot with 6 pin

can i use a stereo pot as a mono pot to controll a servomotor


Hello..am 2 weeks old to arduino projects..i had been using timing all this while to control my rover...now, i wanted to shift to using encoders..am facing quite some problems..am using arduino uno and a two amp motor shield..this is code i am trying to use..am using a 8V Li-po battery

http://www.myduino.com/index.php?route=product/product&product_id=170&search=rover+5 (link to rover)

http://www.myduino.com/index.php?route=product/product&product_id=131&search=motor+shield (link to motoshield)

Dagu Playful Puppy

I purchased the playfuy puppy kit for my daughter to build as school project.  It is the smaller one which I believe is the newer kit.  We got it assembled and it appeared the code uploaded ok. It wasn't functioning as anticipated and I planned to investigate further this past weekend. I did that and now I get the following error message whenever I try to upload the code "avrdude:verification error, first mismatch at byte 0x0000  0x00 !=0x3b.

LMR shop

I just wanted everyone to know how freaking awesome this is. I took FritsL up on the "Buy something for a dollar to test it" deal and then told him not to bother sending the actual merchandise, just to keep the dollar, but it was too late-Gamborg had already sent it! Well, from Denmark to the U.S. took almost no time, and I got the best deal on a tilt sensor ever. Anyway, support LMR and buy and sell some shit through the LMR Marketplace. You can literally get a Propeller for $1 there!

Bluetooth module as a key sniffer on Arduino?

Recently, I've come accros a keylogger in a wallwart charger. It uses a RF transciever, I think. Would it be possible to substitute the RF with Bluetooth?

Issues with my nozzle (Whey!)

I am having a bit of trouble with my 3D printer at the moment, and thought I could gain some wisdom from our 3D printing geniuses (plural?) here on LMR.

My extruder keeps blocking, I am using PLA, printing at 190 degree's, with a hotbed of 57 degrees

The printer is a makerbot replicator 2 clone, called the duplicator.

Flame Photodiode is more like a regular photodiode

I bought a small flame photodiode for a robot Im currently working on. Being a "flame" photodiode I thought it would ignore most light and pretty much only output whenever it gets light from a flame but it seems normal day light can set it off. Even lamps or sealing lights seem to be enough for it. 

Pretty much almost makes it a reguarl photodiode. 

I can get the data from it with this line of code: FlameValue=analogRead(0);

Just read the analog pin.


Anyway I can maybe fine tune it better for flames? 

Can I connect a motor shield on the DFRobot Bluno?

Can I connect a motor shield on the DFRobot Bluno Uno?

I'm planning to use the Arduino Uno compatible Bluno with motor shield, can anyone confirm if this can be done?

[Tip] Make a Simple robot low cost

HI, My name is Mirko i'm 19 years old and i'm a student. For the last year in this school i want to build a simple robot that i can program using some programming language like c, c++, etc..i'm not very rich and i can't spent more then 50$ so i'm asking you if you can suggest me some guide or project to make a robot low cost and not much expansive. i'm searching a project like in the 'Start Here' section. Maybe with IR sensor and the wheels

getting started with nRF24L01

Hello guys I'm trying to send message from arduino due to arduino duemilanove atmega328 using nRF24L01 

arduino due is the transmitter and the code is


Trying to find the largest data value in an array

My robot needs to do a sweeping scan. Im trying to get it to sweep from 0 to 180 and collect data values from each angle. I have that part down. Im trying to read the array and find the largest value.

This turned out to be harder than I thought. So I made a new Arduino program seperate of the robot's code to make things simpler. This code does a scan from 0 to 180 and prints all the data values (Flame Photodiode), then it waits a second and prints the highest value in the array. 

Cheap MICRO USB Control 5V 2-Channel Relay Module $4.56 with Free Shipping

MICRO USB Control 5V 2-Channel Relay Module $4.56

It's equiped with the USB and Serial port which can connect to the PC and other devices conveniently.
The normal working voltage of this module is 5V and it has the 5V power port.

spreadsheet control

How do i get ioio input signals into excel(any spreadsheet) in realtime and control the outputs with excel?

Support me on my trip to Space

I am currently competing for the Hackaday Prize 2015. The grand prize is a trip to space, a dream (yes, just a dream) since my childhood. You can support me by following me and giving my project 'skulls'.

Thank you, LMR!