UC Berkeley's washing machines

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dg1261

Active member
Oct 22, 2020
36
17
Wow, Deja-Vu moment!

I just listened to Episode 1043 (yeah, I'm a few episodes behind), in which Steve described being at UC Berkeley in 1973. He mentioned:

UC Berkeley also provided coin-op washing machines in pre-Internet 1973, when I happened to be there. And, really, what did they expect? The machines had been placed in Ehrman Hall, which was the engineering dorm, where I was. It turned out that the coin-op box that had been added as an afterthought to the machine, had a sheet metal screw in the back, the removal of which created a hole through which a properly shaped length of coat-hanger wire could be threaded.
[...]
with a little bit of fishing around, it turned out, the lever that was normally actuated by the insertion of a quarter into the front could be tricked into believing that that had just happened. So let's just say that I never needed to bring laundry home on the weekends for my mom to wash.
Click to expand...

I'm a few years older than Steve (I graduated in 1973, while he was just starting). I had also lived in Ehrman Hall, and remember those washing machines and that sheet metal screw. The hack had been discovered by some guys prior to us, and the lore had been passed down to us. Obviously, it was still being passed down by the time Steve got there.

I won't mention what happened when a couple of EE students stumbled across the wiring diagram for the elevator controls, but I wonder if that lore also got passed down to Steve's generation.
 
Oh no, I am quite sure that enough time has passed that you can now safely tell us what happened when "a couple of EE students stumbled across the wiring diagram for the elevator controls".

Please do. :)
 
Well, I was not an EE (Electrical Engineering major) or a participant in the hack, so am not certain of all the details, but from my second-hand knowledge I can relate my understanding of how it was pulled off.

They didn't start out trying to hack the elevator, it was just a crime of opportunity that presented itself when someone managed to duplicate one of the RA's Master keys. That enabled access to the roof of the dorm building, and also access to the elevator control room on top of the roof. A quasi "rooftop expeditionary force", including a couple EEs, found an array of relays and a rolled up set of blueprints in the control room, including the wiring diagram for the elevator controls.

The EEs easily figured out how the relays worked -- essentially, the elevator CALL button on each floor would set/energize a corresponding relay, which would reset when the elevator eventually stopped at that floor. (Remember this was pre-digital era, so these were all electro-mechanical controls.) They also identified a Reset line, which would reset/deenergize all relays. IOW, grounding the Reset line would cancel all queued up CALL buttons. The Reset line was accessible via the wiring bundle in the wall behind each floor's CALL button, and this gave the EEs an idea.

They lived on the 8th floor, so they dismantled the CALL button on the wall of the 8th floor, added a magnetic reed switch in parallel across the Reset line, stuffed the reed switch inside the wall, and taped it to the backside of the wallboard in the hallway, about 4-6" to the left of the CALL button. Then the CALL button was reinstalled where it belonged.

Then, whenever the elevator got busy -- such as at dinnertime when everyone in the dorm was trying to get downstairs to the dining commons -- the guys on the 8th floor could surreptitiously place a magnet over a seemingly blank part of the wall next to the CALL button, then press the CALL button. Instead of stopping at every floor, the elevator would go straight to the 8th floor.

The cleverness of this hack was the elevator worked perfectly normally at all other times, and there were no obvious signs of tampering. If anyone reported the elevator wasn't working right, the maintenance guy wouldn't find anything wrong.

It wasn't perfect, and the elevator would still stop on another floor if anyone on that floor happened to press their CALL button after the Reset line had been triggered. But OTOH, that just helped the subterfuge and made it less likely anyone might guess it had anything to do with the 8th floor. While it may not have been perfect, it still saved a lot of time getting downstairs.

I don't know how widely known this hack was. This was probably an expellable offense, so I wouldn't think anyone would have talked or passed the knowledge on to others. But then, I also didn't think the washing machine hack was that widely known, and it startled me when I heard Steve mention it on the podcast.
 
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