Elph Rig Video Downlink Module - built in May 2003
A year ago I started building a video downlink module for rig 2. My motivation was to
improve the framing of my photos - for example, the picture on the right
would look much better if the whole house were visible.
Just tilting the camera up a few degrees would have made all the difference.
Encouraged by the information on Simon Habord's and Olivier Humez' sites and the reasonable cost of 2.4GHz transmitters and receivers at Maplin's, I bought a pair. The Elph outputs video all the time, so apart from the transmitter all I needed on the rig was a 12 volt supply. I built the 5v to 12v DC-to-DC converter circuit on Brooks Leffler's site (using components from RadioSpares).
The total weight of the module is 80 grams and adds just 10% to the weight of the rig.
Although the video rig worked, the project was sidelined while I explored various viewing options. I tried it with a portable pocket TV but (as many others have found) on a sunny day it's very hard to see the picture. I acquired a demountable viewfinder for a Sony CamCorder which works much better, but the various power supplies needed for R/C transmitter, video receiver and viewfinder eventually led me to build a customised transmitter to make it easier to power, carry and operate all the stuff.
||This shows the module on its own. The jack plug goes into the video out socket on the Elph and the other connector plugs into the charging socket of the rig's battery pack. The module has its own on/off switch and there's also a small slider (just to the left of the aerial) which switches between the four channels that the 2.4GHz transmitter/receiver pair can use. Behind the aerial is the bracket for fixing the module to the rig. Inside the plastic box is the transmitter itself and the DC-to-DC converter circuit.|
||A view from the back showing the module attached to the rig with the camera pointing horizontally. There is just enough room between the Elph and the camera frame for the jack plug - a fortuitous accident - when I built the rig I had no idea I would be adding video. If the camera frame had been just a bit narrower the plug would have fouled the tilt servo axle and I would have had to rebuild it.|
||Another view from the back, with the camera pointing vertically downwards. The module is held in place by the plastic bolt that screws into the camera's tripod socket. When the video module is not used, the thin rectangular plate dangling below the rig is used as a spacer. It takes just a few seconds to attach or remove the module. The temporary aluminium legs shown on the construction page have now been replaced with carbon fibre ones.|
||A side view with the camera pointing down at an angle of about 45 degrees. The plastic tube projecting rearwards through which the aerial is threaded serves two purposes - it's a useful indication of the direction in which the rig is pointing and it keeps the aerial out of photo shot.|