Up until now, we have talked about working with a lot of low-power devices. Sensors, LEDs, ICs, and the like are all capable of being powered directly from your Arduino, but as many awesome 5 and 3.3v components as there are, eventually you will find yourself holding a 12v solenoid, motor, or light and wondering “How the heck am I supposed to control this from my Arduino?” Well today we are going to talk about doing just that from a magical device know as a transistor, specifically the TIP120 Darlington Transistor.
Simplified Motor Control Using A TIP120 – [Link]
I had this (wrong) idea that I could communicate with more than two Arduinos through the RX/TX ports using Serial communication. One of the issues is, (1) that it’s not possible to do so … and (2) even if it would, it would not be possible to identify the nodes in the network. Chatting on the Arduino IRC channel, I was suggested to use a protocol such as I2C or 1-Wire.
I2C Communication Between Two Arduinos – [Link]
This is another SIM900-based GSM/GPRS wireless data shield for the Arduino, this one is from Open Electronics:
This is a very low cost and simple Arduino GSM and GPRS shield. We use the module SIMCom SIM900. It’s the cheaper module now available in the market. To connect this module to Arduino I make a PCB that include a LM317 some capacitor filter and no more. I performed a GSM library to control easily the module. The GSM library is a modified version of the library of HWKitchen.
With our version we control the module throw the pin 4 and 5 (so normal digital pin) and our GSM library include also the NewSoftSerial, so you can easy control the module, send and read SMS, make call, control the GSM state ecc.
To download schematics, PCB and Library check the site
Yet another Arduino GSM shield – [Link]
Here’s a keyboard-glove prototype in development by Jeff Rowberg. The Keyglove is a glove-based USB input device that provides full keyboard control, designed for wearable and mobile computing and to assist the disabled. [via]
According to Jeff:
The Keyglove is a portable Arduino/AVR-powered glove that uses touch combinations (for keys) and an accelerometer (for the mouse) to generate keyboard and mouse control codes using only one hand. Once learned, the glove can easily be used without looking, making it perfect for embedded/wearable environments. The glove is thin and light, built to allow other activities (such as writing) without being in the way. The current design also incorporates Bluetooth wireless connectivity, a rechargeable lithium polymer battery, simple vibration feedback, audio feedback, and a tri-color status indicator LED.
Keyglove Arduino/AVR-powered keyboard substitute - [Link]
Tronixstuff has posted this classic Tic-Tac-Toe game using the Arduino and the Sparkfun LCD shield. User input is via a homebrew button board. Two variations of the Arduino sketch are provided, along with a simple schematic for the button connections.
Arduino Tic-Tac-Toe game - [Link]
Arduino based POV globe capable of displaying monocolour bitmaps upto 72 pixels high and x width. (uses 72 LEDs, and one input to get rotation speed)
Arduino byte array for images are generated using the c# program included in this project
Image displayed is synch’d to speed of motor using a reed switch, this allows image to display around hole globe correctly, and maintain a constant position.
Code has been added to move the image slowly (so globe rotates nicely)
POV Globe using arduino (atmega328P) and 72 SMD Leds – [Link]
I have been busying myself recently with some experiments into programming the Arduino prototyping platform.
I have already created some hardware, a Maxim DS1307 Real Time Clock shield and a Serially Interfaced, 8 digit 7 Segment Display based on a MAX7221 IC. So far I have created test routines to test my hardware but I wanted to really get my teeth into creating some more practical code.
And here it is, A more or less functioning LED clock.
Arduino Cloc: A Maxim DS1307/MAX7221 Based Clock – [Link]