Strobe Quench Controller Power Supply - Part 1
I had gutted a SEA & SEA TTL C converter and was replacing the innards with a home brew Arduino board that would provide a strobe Quench controller. To review: the Quench Controller would allow me to manually control the power output of my strobes (up to 2 sets of 2) from a single control knob on the TTL converter housing.
But I needed to provide power for my Arduino replacement board located inside the TTL converter housing. I had the following options:
- steal power from the camera
- steal power from the strobe(s)
- use an onboard power supply
The camera (Canon G16) did not provide any useable power source - especially considering that I would need to route the camera power to the external TTL converter housing via the "standard" Nikonos 5 wire cable. So the camera was a non-starter. Strobes on the other hand do provide a handy 5 volt signal. At this point in time I was experimenting with a spare YS50 strobe. It provided a 5 volt source via the X signal line (I am not sure how much current). But this signal line needed to be dragged to ground to fire the flash. It seemed counterproductive to short your power source to ground. So I discarded that idea. Newer Nikonos compatible strobes provided a 5 volt signal on both the X and the RDY signal lines. I am unsure if the SP signal line could be used. Heinrichs Weikamp has figured out how to do this for their Digital Adapter and Remote Slave Unit (RSU), so it is possible.
I opted to pursue a self contained onboard power supply. The SEA & SEA TTL converter included a user replaceable battery compartment (craftily isolated from the internal compartment so that a battery flood had limited damage). Next question was how much power did I need? The Arduino board I had chosen was a 5 volt model. This was based upon the Nikonos wired protocol using 5 volt signal levels. My minimum preferred dive time was 60 minutes so I wanted at least 90 minutes of power. A whole week would be optimal, a whole day (3 to 4 dives) would be satisfactory.
The original TTL Converter used a CR-2 battery. Not common, real expensive and not enough volts for me (3 to 3.6 versus the 5 I needed for my chosen Arduino). So how to provide 5 volts from a battery compartment designed to hold a CR-2? The second issue was could I provide enough current?
A CR-2 is 15.6mm diameter and 27mm in height (length? Depth?). A lengthy survey of standard battery sizes and a further filtering of battery's commonly available in my neighbourhood revealed that there was no suitable 5 volt drop in replacement battery.
Time to improvise. During my battery research I had discovered a commercial battery that was just a stack of 4 button battery's shrink wrapped together and resold at a premium, Maybe I could make my own battery?
The 15.6mm diameter was my first restriction...