Drawing an Arduino Circuit Diagram


I've had an Arduino Duemilanove now for a couple of weeks. If you're not familiar with the Arduino, it is "an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software". It has a small microcontroller, a USB port to connect to your computer for programming, a power socket for providing power when the USB cable isn't connected, and various digital and analog input and output pins, for connecting up to leds, switches and various sensors.

It's inexpensive, and there's an open source IDE for programming. Works great, but one issue that I quickly ran into was remembering my circuits. I'd make something up on a breadboard, write a program for it, and then tear it apart to build another circuit. When I wanted to go back to an earlier circuit, I had the program saved, but I couldn't always remember how I had wired up the circuit.

So I went looking for a program that would let me document my circuits, and I found Fritzing. It's very easy to use. You drag parts off a palette and connect them up with drag and drop. You can work on a breadboard view or a schematic view, and they are automatically kept in sync. You can easily put bends into wires to route them in more visually appealing ways.

Jabra SP700 Bluetooth speakerphone


I have been looking for a way to listen to music and podcasts on my IPhone 3G while driving to/from work. My current solution of wearing a headset was less than satisfactory in convenience, comfort and safety. I have experimented with a cheap FM transmitter bought at Walgreens, which plugs into a car cigarette lighter for power, and has a 3.5mm jack to connect to the IPhone. But reception was unbearable, and it was inconvenient when a call came in.

My Mazda6 doesn't have an audio input jack, or a tape drive. So there was no convenient way to play the IPhone over the stereo. I did find a product called Auxmod that could be used to add an audio input jack. But at $60 it wasn't cheap. Plus it seemed that if the connected device was also powered from the car cigarette lighter, then some additional shielding was necessary to avoid interference, which cost more. And installing the device involves pulling apart the dash.

The other device I explored was the Parrot MK6000. This was where I learnt about bluetooth streaming or A2DP. This allows stereo music to be streamed from something like an IPhone to a bluetooth device like the MK6000. The neat thing about the Parrot MK6000 is you're not having to plug in the IPhone to it. You can be playing music or podcasts, and when a call comes in, it just breaks in. And the device can be wired into a car stereo. But it's the latter that gets complicated. The only way I could see to wire it was to buy and install the Auxmod, or to get a professional to do it. And the ones I spoke to were quoting prices in the $200 range for installation. With the Parrot MK6000 itself costing $110 this was an expensive approach.