Will O’Brien developed this project allowing him to remotely start his car via an SMS sent to a jailbroken iPhone. The additional hardware involved is an Arduino, iPhone breakout board such as the PodBreakout Mini, 4x 10k resistors, 1x TIP120 and a 5 volt switching supply cell charger.
All the details, including source code and schematic are available on Will’s Biobug website
DIY iPhone remote automotive ignition - [Link]
Nothinglabs has posted their circuit for a simple reversible motor control for use with the Arduino and other MCUs. The circuit uses two TIP120 Darlington Transistors, two 220 ohm resistors and a 12 volt DPDT relay, parts easily obtainable at any Radio Shack. This design supports PWM for variable speed control, handles loads up to 5 amps, and is controlled using just two MCU pins for “enable” and “direction”.
Reversible motor control for Arduino and other MCUs - [Link]
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]
Aki writes:The electric circuit board for controlling stepper motors came out after figuring out all the specifications of the components. Some sketches were necessary to done. Then Auto-Cad was a great tool for drawing the wires and locate the components. Mainly my circuit is similar than shown in Mel’s page. I didn’t use opto-isolators and couldn’t find TIP120 from a local electric dealer, so I used TIP122 transistors. I also placed the small hand-pad diodes on the board instead of installing them inside of the hand-pad. After soldering work and changing the InverterOutPut (!) to 1 the board started to work. [via]
Stepper Motor Circuit Boards - [Link]