Wednesday, November 25, 2015

Tackling the battery box

The back box of the Star Laser Force pack is pretty much all batteries, which is not uncommon in the industry to this day, although technology has vastly improved since then! Each of the three separate power supplies used conventional NiCd cells.

View of the aluminum box on the rear of the suit, packed with rechargable batteries of various sizes
All hand built, too.
The single remaining AA cell was removed due to corrosion.

The pack has standard D, C, and AA carriers, which are not wired; instead, the solder-tab cells are connected with short wires and stuffed into the carriers to keep them from ratttling around. A block of foam on top kept them in place and quiet. Each supply is fused. All the fuse holders were the cheap type with weak metal, so all the fuses were a bit loose.  From numerous personal experiences in electronics repair I can guarantee that these low-quality fuse holders were the source of horrible, intermittent problems with the packs during their lifespan.

The largest power supply is the 2-cell, 2.4V full "D" size which is routed to the gun. These were date-coded 1984 and could have been original. The gun, which used a xenon flash circuit from a pocket camera, consumed more current than any other part and required the large, dedicated battery pack.

The 4-cell full "C" size, at least one of which seems to be dated 1985, furnishes 4.8V to the 5V terminal on the logic board.

A chain of four cells connected in series with thin wires
They had to solder the wires into place. Spring-loaded clippy connections just won't stay in contact in a high-vibration wearable device in "combat."

Also in the pack being refurbished there was one full "AA" cell which got removed immediately on arrival due to corrosion. This appears to power the two sound boards that are in the front box. With wires broken due to corrosion it's not clear whether there were more "AA" cells.  I'll conduct some experiments and see if the sound circuits will even power up.

The back box also includes a 4PDT power switch (which disconnects all three supplies at once), one team LED, one sensor, and a "Euro-style" barrier terminal strip. The helmet attaches to the top of the back box; helmet signals and the LED and sensor pass through the fixed left shoulder harness to the front box.  The right shoulder harness, on the other hand, can be disconnected from the front box and plugged into the vesting room battery charger.

[Side note: I have a (transcribed) note suggesting that cylindrical 2 volt Cyclon SLA batteries were being used, or at least tested, as replacements for one or another of these power supplies. (I'll try to dig up and interpret this data at some point.]

The placement of fairly lightweight batteries in the pack, rather than providing a separate, heavy battery belt as was used in Photon, was a key advantage of Star Laser Force in its time, and this design is still in use today in arenas around the world.

SLF was very primitive, but considering what was available to the engineer in the early 1980s, it made practical sense to build the system this way. It wasn't until the introduction of affordable, mass produced cordless telephones that the modern battery pack became readily available outside specific uses. Today these pre-soldered, pre-wrapped, robotically assembled units come ready to connect to phones, power tools, R/C vehicles and drones, and have considerably greater current capacity as well.  For the laser tag player of today, it's a better world.

1 comment:

  1. It is interesting to see this. My dad got in to video stuff early on, and we had a luggable VHS recorder and separate camera that we took to Walt Disney World in 1982. It had packs that inserted in to it, and when I finally saw SLF a few years later, I assumed they were just using camera batteries like this. interesting.