Arduino I2C expansion I/O

Did you have a situation when you ran out of microcontroller pins. Especially when you do lots of interfacing, adding many buttons or LEDs then you definitely need many I.O pins. Sometimes you can use more advanced microcontrollers, but this isn’t best solution especially when you don’t need much processing power. Why not to use I/O port expansion? Keith decided to experiment with I2C port expanders connected to Arduino board. He used Texas Instruments PCA9535 and PCA9555 16-bit I/O port expanders – one for inputs and another for outputs. This way he managed to add 16 additional I/O pins by scarifying 2 MCU pins. Author has provided a generous description about whole process and even gives us a program code for trying. Continue reading

Geeky 3 meter clock system

Seems that Arduino rocks the world. More and more great projects appearing that are built around Arduino board. And this is great because it allows to focus more on creative things than on MCU routines. This project caught my attention because of its uniqueness – it displays a time on three analog panel meters. And this is not all this clock can do – it also updates itself by logging to SNTP time server via Ethernet Shield. Adafruit Proto Shield allows easy interfacing of analog panel meters. Arduino sends time as PWM signals where OP-AMP drivers scales them to display time correctly on panels. I think this is great project to make your working table even more geeky. Continue reading

Playing real music with Arduino

Usually in electronic projects people choose to use low quality sounds like ISD chips with 8 kHz sampling rate, direct PWM, or end up with MP3 decoders. Las option is to play uncompressed audio files from SD/MMC card via DAC. Such solution can give good sampling rate and good quality especially when sound is filtered and amplified with op-amp. This project is set up around Arduino board. It takes wave files from CD/MMC card and plays them asynchronously as an interrupt. So there are resources left for additional tasks between them. It can play 22 kHz, 16 bit mono wave files of any size. Files are stored in FAT18 formatted media card – so it is easy to upload new files via standard card reader. All files and libraries are downloadable or as usually you can order a kit to enjoy the music. Over all project is well described – I recommend to read even if you aren’t going to build one. There are some good materials about audio sampling and interfacing SD/MMC cards with arduino. Continue reading

Be a Guitar Hero with Guitar Midi Controller

If you like to y guitar, maybe you should try to do this with Guitar Hero Midi Controller. It uses well known Arduino board to interface Guitar with external MIDI device. With the current version you can: play 2 octaves of an 8 note scale at a time; change the starting note anywhere in the range of a regular keyboard; change octaves’ change keys; change tonal modes (Ionian, Mixolydian, Lydian, Dorian, Aeolian, Phrygian, Locrian); change the timbre of a sound; change the resonance of a sound; use the whammy bar to pitch bend; play chords in the mode you have the guitar set to (major/minor/etc.); rock out with a video game toy. I think this is a great way to make your defective guitar useful. in order to make the program run, you’ll need a MIDI library and guitar library. Project is well documented and illustrated. It shouldn’t be very difficult to rebuild. Continue reading

Cute autonomous Para poetic device

Electronics can be romantic. The Autonomous Parapoetic Device is a self-contained and portable machine that generates poetry. The idea is really great – electronics is packed in a nice wooden box. You just need to open it and 20×4 LCD screen shows poetry. All this joy is driven by ATmega168 microcontroller programmed with Arduino (source). This could be great geeky gift for your beloved one. Continue reading

Arduino based CrudBox

It can remember 4 different loops. You can see which one you’re one on the 7 segment display and scroll to different ones with the rotary encoder knob next to it.  The tempo can be seen on the 4 LEDs in the lower right corner. “There are 4 speaker terminals on the box, into each of which you can plug any object that can run on 5 volts. In the video I’ve plugged in LEDs because it makes the interaction clearer, but my main interest is in plugging motors in, attaching them to the box, and amplifying the sounds they make. Each speaker terminal has a button and a pot. Pay attention to which of the 4 tempo LEDs is on, then press a button, then let go. It will switch on the object (motor, LED, etc), then switch it off when you let go. The next time it cycles through the loop of 4 LEDs it will switch on and off at the same points. The object will pulsewidth modulate at different speeds depending on what position the pot… Continue reading