Step 7: the Control Box
Now to make the brain of the matrix. Its real simple like a dinosaurs brain but needs to be pretty robust if you are going to take it in the field.
The control box will have a grid of switches, one for each camera. It will also have 1 master switch to rule them all. In most scenarios you will have the individual camera switches in the on position, and then toggle the master switch on and off to take photos. Putting a switch on each camera makes it easier to debugging problems and can be used in a number of new ways to create content.... and it makes your control box look really... intense. In addition to the switches, the control box will need two kinds of terminals that will allow you to quickly plug in the camera cables.
To make the box you will need:
- a drill
- a soldering iron
- liquid flux
- (25) SPST switches
- (2) power terminals
- (4) 6 channel screw down terminal blocks
- a large plastic enclosure
- stranded wire 24 AWG
- wire ties
- wire anchors
These parts can be found in your local hardware store or radio shack. See Materials List in Step 1 for links to parts.
( see the scan of a hand-drawn [.:.:.] schematic for the detailed circuit and control logic table in the images below)
Drill all of the holes needed in the box to mount the switches. We used 4 rows of 6 switches on the top face of the enclosure, and one master on the front side. We mounted two 6 channel terminal blocks on each side of the box (for a total of 24). To feed the connections from the terminal blocks to the switches we drilled 12 small holes on each side of the box. Finally we drilled two large holes on the side of the box for the power terminals.
Mount the switches using the mounting hardware they come with, including the master switch. Use the washer they provide with the switch and drill a very small hole to utilize the small tab on the washer. This will keep the orientation of the switch consistent so you know what's up from down.
Mount 2 terminals on each side of the enclosure, using the self-tapping screws provided. You can screw them directly into the plastic. Drill a small hole above each terminal for you to pass conductor inside the enclosure.
Solder a stranded wire to one contact on each SPST switch, then feed the other end of the wire through the corresponding hole leading to the terminal blocks. Cut the wire to length, strip it and screw it into each channel of the screw down terminal blocks on the side of the enclosure (See photo below).
Solder a stranded wire to other contact on each SPST switch, then solder the other end of the wire to a single continuous bus (camera control bus) on the component or perf board. You are connecting all the of the control cables from the camera together.
Solder a wire on one contact of the master switch. The other end of this wire can be connected to the camera control bus on the perf board. Solder 2 wires to the other contact on the SPST and the solder (or attach via terminals) the wires to both of the two power terminals on each side of the enclosure. You can mount you perf board on the lid of the enclosure or just cram it into the box. You already know which one we did.
At this point your brains should be online and ready to go. Label the terminals and each switch with a label maker, tape + a sharpee or a paint pen.