I recently added this project to my blog, if you don't want to wade through all the how to 'ness then this summary might be better to read.
I made it as part of the Gift Exchange.
It works by sending out a modulated infrared signal. The detector then senses any of the reflected signal, this is how it knows if anyone has passed by.
The main board contains a pickaxe chip. There is a mode select button which allows you to cycle through the different detection methods and alerts.
It runs off of 3 x AG-13 button cells and can sense up to 15cm+ in good conditions.
For a demo watch this video.
I also made a couple of instruction manuals which are attached.
Instructables reduces the image quality of uploads so I've included a PDF with all the diagram illustrations at high res.
Step 1: Materials
I've included links to techsupplies.co.uk so you can see what the pieces look like, as well as places you are likely to find the component.
Components: Likely places to find them:
- Picaxe 08M chip
- Perf / strip board
- IR sensor 38kHz
- 2mm red LED
- 5mm IR LED Any Remote control
- Piezo transducer Anything that makes a beep noise
- 6mm tactile switch Anything that clicks when you press it
- PCB mount slide switch
- Resistors with rough values of 32k, 10k, 1k, 300, 180 Ohms
- <1.2mm insulated wire
- Button cell battery contacts Anything powered by button cells
- 3 x button cell max size AG-13
- Small nut & bolt
also a Zippo style lighter, or other pocketable housing
(small altoids tin etc)
- Soldering iron with fine tip
- Drill with 1mm, 2mm, 4mm and 12mm bits
- Small files / sandpaper
- Needle nose pliers
- Side cutters
- Tin snips
- 2 part epoxy glue / hot glue gun
- Pva glue / nail varnish
These images show what I was able to get out of a broken electronic die.
small electronic things like this are the best place to look for battery contacts.