In Part I, we discussed the game and how to pick up the wand data using a common IR receiver meant for remote controls. In Part II, we discussed a routine for parsing the pulse-width IR data into bytes suitable for further processing.
We put our newly-discovered knowledge to use in building up a little circuit to make Magiquest wands “magically” do stuff. It’s centered around a PIC12F508 and Radio Shack IR Receiver Module that watches for a wand shake, then actuates a relay to power a light, sound, or other effect of your choosing. We’ll actually show two versions, one running from a single 9V battery that can actuate a smaller 1A relay, and one that runs from 12V (or 2x 9V batteries) that can run a more heavy-duty relay. Some simple options are programmable via header pins and DIP switches, but more about that soon.
The MQ Widget
The widget is sized 1.175″ x 3.625″ so it can fit inside a low-cost 3/4″ junction box available for a few bucks from your local big box store. The specific junction box used was called a 3/4″ PVC Conduit Body, C Style. Although it’s not easy to find on the Home Depot website, it was right there in the conduit section of electrical. Manufacturer is CANTEX.
There’s enough room inside this cheap watertight enclosure for the board, battery, and to feed through a chopped off outdoor extension cord for the relay to activate. Our store was out of gray Cantex plugs for the endcaps, but 3/4″ white PVC plugs fit just fine. Drill holes in them to feed the extension cord through, then drill a hole in the side of the enclosure for a little plexiglass window for the IR receiver, and you’ve got yourself the makings of a great outdoor Halloween effect for the kiddies.
MQ Widget Features
Header-programmable momentary or toggle on/off function – Blink a light, play a sound, or run a fog machine (with a fatter relay, of course) in momentary mode, or turn on and off your lamps, TV, coffeemaker, all with a magic wand!
DIP-Switch selectable momentary time – Choose time from a minimum of 200ms for triggering an external effect, to 5, 10, or 60 seconds for longer effects or operating secondary equipment.
RS-232 Wand Data Output – Read out your wands with a PC, or extend the widget with some kind of crazy networking scheme. Warning: 5V RS-232, needs FTDI or MAX232 to interface PC.
Built In Debounce – Tested to avoid double-triggering, even with the wildest of kid-wand-shaking!
Open Source and Freely Hackable – Soon, you’ll get the schematics, PCB layout, PIC code and hex files. Have at it.