Archive for ‘Arduino’


Music in the Shower!

I’ve been working on this for a long time but I had some trouble geting it out of the breadboard and then iTunes changed the APIs so I’ve been trying to get it working again but for the mean time I’m leaving this video from the initial stage:

I’m using an Arduino to send the commands to the computer via bluetooth (next track, prev, play/pause, volume, random playlist). The computer is running a python script to get the commands and send the appropriate signal to iTunes, and getting the song info back to the Arduino.

The python part changed recently due to the APIs update and it doesn’t seem that I’ll be able to get it working back in the same way.

Right now I got it working again with the API changes with some workarounds with some .app’s created with AppleScript that only send the play/pause, volume, etc., one for each command, but I don’t like this approach so I’m trying to get it working as a service again.

I also want to have a good case for the board but in the mean time I only tossed the circuit inside a ziplock to avoid the water.

I hope to give an update soon.



For the Mechatronics Projects class on the last semester we had to build a functioning robot.

Me and my team came with the idea of automatizing a restaurant with a waiter robot, but we figure it out that we could very well automatize the whole experience of ordering food in a restaurant.

We started creating a web app for ordering (and paying) the food that could work on any smartphone or laptop.

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Project for the signals processing class.

The user creates a JPEG file with a certain pixel by pixel size, divided in 64 squares. Those painted different than white will be showed in a LED matrix.

Created using Processing and Arduino.


Full Rotation Servo

Last time I wrote I told you that I had new toys from sparkfun. Two of those were full rotation servos (also: buttons!).

When I bought them I though they were 360ยบ servos but instead they are servos that rotate indefinitely, so they don’t have position control, but they have speed and direction control. Also, they feel very strong.

This is a little program that I did to test the servos:

Two buttons are used to control the direction and the speed and it is displayed in the LCD display.


Sparkfun FTDI 3.3V or 5V

I noticed that Sparkfun sells FTDI breakouts in two configurations: 5V and 3.3V.

I have an old one and a new one, both 3.3V. One thing I noticed is that the new one had 3 solder points on the far side so I started investigating and realized that this is the voltage selector.

There are several reason why you would want to change the voltage, specially if you have two of them. For me, the reason was that my LCD screen is 5V and I didn’t want to alternate an external power source and the FTDI to upload the program and testing it.

Both look the same, difference is on the far side.

So, if you want to change the voltage of you FTDI breakout all you have to do is connect the solder points. If are seeing the board with the USB on to the left, connecting the top and the middle points provides 5V; on the same way, if you connect the bottom point with the middle you get 3.3V. Make sure you break the existing connection with a knife to avoid a short circuit.

Converted FTDI. A drop of solder will do.

Happy coding!


Very basic interface with Arduino and LCD screen

This is a little something I started working with this week.
I bought a Serial LCD screen from Sparkfun last year and I just realized that I have never used it.

This is as basic as it gets. Two buttons for cycling through the options and one button for action.

The next step is adding PWM and controlling it with another two buttons and maybe a setting screen for setting up the brightness of the screen.

By the way, if you get an LCD from Sparkfun make sure you select the correct voltage. I bought mine 5V but my two FTDIs are 3.3V. I had to convert one to 5V to avoid using an external source.