WMD Part II by G-gnome

Timer - Pulling It Apart

In the front of the case is its most dominant feature: a huge, red LED timer. This is a CK-3000 countdown timer from ElectronicsUSA. In fact, it was probably the timer that gave me the inspiration to build a WMD-type mod in the first place; I know I had it at least a few months prior to even starting the project.

The website claims that their clocks and timers are used in US government establishments and research facilities including military bases and even the lab at Los Alamos (the home of the atom bomb). What could be more perfect for this project? The timer is the count up/down model and will count down from a maximum of 99hours, 59min, 59sec. The idea behind the timer (besides the whole cliché movie-bomb-thing) is to enable the case to go to an event or show and the timer can count down the seconds until the show ends. The timer came in its standard, plastic housing.



I was curious to see what was inside and took it apart. Initially, when it arrived, I thought I'd have to make the timer cover the same size as the original case. Luckily, when I opened it up, I saw there was a lot of wasted space inside, and that the LED board was quite narrow; barely wider than the numbers.



A lot of LEDs! I liked the way the numbers were displayed using round LEDs instead of the usual 7-segment display. Another thing I found was that the LED board was only connected to the PCB by 15 wires: 13 at the bottom edge, and a pair of wires in the back. This raised the possibility of mounting the LED board at a distance from the controller PCB, which would enable a much narrower timer box.



There were jacks for a remote programmer and power.



Two power jacks, in fact, plus an enormous alarm. Comparing the size of it to smaller ones in the local electronics shop, I estimated it would be ear-shattering; after all, these timers were designed for industrial applications. Later I stuck some earplugs in and tested it - yep, woke the neighbours!



The PCB has a switch on it for the alarm. The socket for the remote cable is the same sort as a network socket.



There is a battery backup in case of power failure (the numbers aren't illuminated, but it keeps the timer going until the power is restored). The number on the back looked like an NSN - very government. Also, as the timer runs on 12v AC (not DC) it has to be powered from a mains adapter. This is because it uses the frequency of the AC current to keep time, and I had to specify, when ordering, that I wanted it calibrated for the 50Hz that Australia uses. If I should run it in the USA (with its 60Hz mains) the timer would run a little faster, though the difference can be calculated and allowed for.



I also discovered the connecting wires to be a standard width. Easy enough to cut off, leaving a short length, and use a standard-size plug to connect later. The CK-3000 remote is a small, heavy duty plastic box.



I took the remote apart and had a good look. The switches looked standard and easy enough to solder wires to.

The plan was to be able to run all the remote controller functions from the keypad on the case. The up / down timer switch would be run to a switch in the cable-bay.