It all started out with an idea : create something that will make LEDs glow on and off, and change the rate of that glowing whenever someone gets near the LEDs. So we've bought the parts, we've made a system prototype, and we've wired up an output. Now all we have to do is package it!
There are several ways of putting together your final project. The "best" way of going about it is to make a Printed Circuit Board . PCBs have long lifespans. are easy to assemble, and look nice. In the past 5 years it's been much easier for individuals to design and purchase custom PCBs, however it can still be cost prohibitive. There are many methods of making PCBs yourself, though they involve some chemicals and lots of drilling.
For this project I decided to go with the old Wire Wrapping Technique. The process of assembling the circuit tends to be longer than with a PCB, and the end product is not quite as visually appealing, but you save time and money on the design /purchase of PCBs. Wire-wrapping is ideal for small projects or projects with a very limited production scale (like this one: I'm only making one of these devices)
Here's a shot of the finished board. You'll recognize the crystal oscillator and the ATMEGA chip on the left from my Parts blog post. The two parts above the crystal oscillator are capacitors that adjust the frequency for the circuit. Directly to the right of the ATMEGA chip are 4 resistors and 4 Transistors. These devices create "buffer circuit." Since the ATMEGA has a limited amount of power it can supply out to LEDs, we need a buffer so that the ATMEGA chip can control the LEDs, but the buffer can supply the needed power.In the upper right corner there is a voltage regulator. This particular regulator has a 5-volt output and up to a 35-volt input. This means that I can plug the circuit into a voltage source anywhere between 5 and 35 volts, and still get 5-volts to my circuit. This is handy because I can use a variety of power sources to run my circuit, and I know I'll be getting the right voltage.
I've built projects in altoid tins, tupperware containers, and cardboard boxes, but if you want to have something a little nicer looking, an ABS plastic project box is a great way to go. You can buy plastic project boxes at Radio Shack or any other electronics parts supplier. I drilled several holes in the project box so that I could connect all of the input and outputs through different jacks. Here you can see the power switch for the project, as well as as a green power LED.
My ultra-sonic sensor needs 3 wires - 1 for power, 1 for ground, and 1 for the actual data signal. A headphone jack is perfect for this since it supports 3 wires (normally 1 for ground, then 1 for left sound, and 1 for right sound).
The power port allows me to easily plug/unplug the power adaptor to my box.
The four output ports are normal RCA jacks. All the jacks have the same output for the glowing LEDS, but each one is on its own buffer. This means that each strand plugged into the box draws its own power and won't interfere with the other strands.
Here's a picture of the box with the ultrasonic sensor attached. Just add lights and power, and you've got a finished project! I've shipped this to my friend, so I'll update here when I have some pictures of her finished project.
I plan to keep everyone posted on my progress with this projects. Next week I'll start showing off some of my projects for an art show I have later this month. If you have any wiring or technical questions, or just have any questions/comments, post below!.
