I just built a wireless USB button using really simple parts. A quick description:
I used this cheap wireless doorbell so the range is about 100 feet, though I haven't tested the range yet:
ACE TRADE- HEATH ZENITH AC6150 CHIME DOOR WIRELS OFFWHT . I like it because both the button and the receiver are battery powered. I bought it at a local Ace Hardware (ubiquitous in San Francisco) for $19. Note that its the same doorbell as this one, but rebranded:
Hacker's Bench : Wireless Doorbell Hacking 
Remove the speaker, then put this relay across the speaker wires:
RadioShack.com - Cables, Parts & Connectors: Component parts: Relays & transformers: Compact 5VDC/1A SPST Reed Relay
Now when you press the button the relay should be triggered. Note that until I removed the speaker, the doorbell didn't produce enough current to trip the relay.
Now your wireless button can trigger any external switch.
For the camera part:
I used this voltage regular, as suggested by a previous poster:
RadioShack.com - Cables, Parts & Connectors: Component parts: Transistors & analog ICs: +5V Fixed-Voltage Regulator 7805
Connect a 9v battery to the voltage regulator's input (positive line of the battery to the input pin, negative to the ground). Obviously one of those 9v battery sockets from Radio Shack (a bag of 5 costs $2) is handy here.
Then splice a USB mini cable. Mine had 4 wires: red, black, green and white. USB mini has 5 contacts, one of which usually isn't used; two are data; two are power. You want to connect the positive power (in my case, that was the red wire) to the output pin of the voltage regulator, and the negative power (black wire) to the ground of the voltage regulator.
Obviously you should figure out which pin on the USB cable goes to which wire. I used this chart and a multimeter's continuity mode:
Tech Info - USB & Firewire
Now connect the output pins of the relay in-line with the output from the 9v battery, so when the button of the doorbell is pressed, the voltage regulator gets 9v power, which sends 5v to the camera, which makes the camera do whatever you want it to do.
Remember to enable the USB button in your firmware.
Here's a crappy picture before I put everything back together.
I should note that the link at the beginning of this post to the guy hacking the wireless doorbell is a more complicated circuit and probably much more correct. But mine works just fine for my purposes.
Here's a basic script to test it out. I'm using AllBest, not sure about other builds:
@title Remote Button
while 1
wait_click 1
if is_key "remote" then shoot
wend
end
Here's my timelapse script that has a couple of nice features:
- shoots a picture every X seconds
- prints how many seconds remain until the next picture is taken
- if the USB button is pressed, it takes a picture and resets the countdown for the timelapse. Handy for emphasizing certain moments in your timelapse.
@title Timeless Lapser
@param a Interval (Seconds)
@default a 10
print "Timeless Lapser!"
rem shot counter
b=0
:looper
b=b+1
cls
print "Shot ", b
print "0 seconds until next"
shoot
rem routine to pause in a way that will show countdown on console
x=0
:pauser
r=a-x
x=x+1
cls
print "Shot ", b
print r, "seconds until next"
wait_click 1000
if is_key "remote" then x=a
if x < a then goto "pauser"
goto "looper"Feel free to email me with any questions, wrybread at gmail dot you know what.
Edit: I've since made the modification from that "hacker's workbench" page, and it indeed works better than my simpler mod. It simply involves shorting one of the resistors, and installing a single capacitor, and the unit is much more responsive now.
