September 26, 2010

IR Sensor for Arduino

Since I plan to use this really great IR library, I've built an IR sensor using an IR module I salvaged from a broken VCR. This module is very similar to a TSOP17.. module:

so I've used the circuit suggested in the TSOP17.. datasheet:

Testing the circuit on a (mini)breadboard it works well (here I'm using this microcontroller board and an LCD to show decoded codes):

The IR library is really good!

Here's the schema of a realization of this circuit on a stripboard:

And here is a realization of the IR sensor, ready to be plugged to the microcontroller board:

September 13, 2010

iPod Touch charger from any USB source

Thanks to this great work from Adafruit coming from Limor I was able to make a simple circuit to let my 2nd Gen iPod Touch (running the latest iOS 4.1) charge from any USB source, not only from PC or from original Apple chargers, but also from any USB charger.

Here is the schematics I've used:

To match the resistor values I've used a couple of 1% resistors to get the nearest value I could (with the values I had).

Here is a picture of the extension cord I've made, together with the small stripboard to host the voltage dividers.

The voltage measured across pins 3 and 4 and ground is very near to 2V for each pin. The extension cord allows to adapt any USB charger to work with my iPod Touch 2nd Gen (with iOS 4.1).

I guess the same works also for iPhone.

September 12, 2010

5V & 3.3V Combined Voltage-regulated Power Supply

Here's a picture of the realization of a 5V & 3.3V power supply, combining this 5V and this 3.3V power supplies on a single stripboard, with differentiated switches and some pins to provide power.

YAMA2 - Yet Another Minimal Arduino 2

Here's a picture of another minimal realization on a 14x16 stripboard, following the schematics of this other one, without the on-board regulated power supply.

September 5, 2010

SD Card Interface

Thanks to this post on the Arduino Blog, I've managed to realize a simple SD Card interface to connect Arduino to an SD card (not only for data logging, but also for data reading - e.g. configuration info, etc.).

This is the schematic I've used, based on a MC14050B Non-inverting Hex-buffer to adapt SD card 3.3V levels to 5V levels of Arduino.

As 3.3V supply I've used this one.

Here's the realization on a stripboard:

The SD card holder has been soldered on a small piece of stipboard (on the strips side):

Here it is:


Here's another implementation following the same schematics. It uses a more stripboard-friendly version of an SD card adapter salvaged from the first version of the official Arduino Ethernet Shield (that has this adapter on-board but does not have all the circuitry to correctly interface to an SD card).