Pelican crossing doorbell project , part 2

When last  I mentioned the pedestrian crossing project, we’d just got the button box open. It didn’t take long for me to wire up the bulb to a mains lead and get it plugged in…


It was glorious. I’d already cleaned off the stickers and filth that had amassed on the button box over the years (a trip to Pound World had equipped me with scrubbing brushes and wipey things for another project) – now it was time to turn my attention to the beacon thing itself. (An aside – I don’t know the correct terms for these things, in case you hadn’t noticed. It may be called a Head Unit in the trade. Contact a civil engineer if these things concern you.)


I put a small tarpaulin across the kitchen floor (from Pound World – hurrah for affordable products) and started figuring out how to get inside the lights. It didn’t take long. I’d had a notion that the lights were modular and could be reconfigured in different ways, but I hadn’t thought about the fact that the entire light boxes were interchangeable – each one is an entirely self-contained unit, proven by the fact that these ones have their own individual transformers inside instead of sharing one for the beacon as a whole.


Getting it apart meant I could wash a decade or so’s grime off the lenses of the lamps and, in doing so, I discovered why those transformers were required. Rather than using mains voltage incandescent bulbs like the button box used for the WAIT sign, this pedestrian crossing was equipped with halogen capsule bulbs. 12V, 50W (so a smidgen over 4 amps a piece, electrical current fans) kicking out somewhere around 900 lumens (roughly a 60W incandescent bulb). OH HOW EXCITING THIS POST IS!


The red man unit had all the wiring coming in at the back, so it was pretty full of wires – but an inordinate number of wires were disappearing into the green man unit. This turned out to be because, lurking behind the lamp , there was a Radix control unit – a mysterious, sealed box of intrigue! It appears this was responsible for running the operation of the button box because the labels on the side refer to the sounder and Tactile Control Unit (the fancy term for that weird spinning nodule on the bottom of the button box) and the wires that were attached matched the colours of those we found when we forcibly entered the button box.

I really want to open up this control unit but it can’t be done non-destructively. Boo. I know it’s going to have some sweet switching hardware within – maybe I should write a fan letter to Radix, who make both it and the Tactile Control Unit, and tell them how hot they looked last Tuesday.


With everything cleaned, and having already had the WAIT light working, I had to get red and green men illuminated to keep me happy. Enter Pound World again, where I got a domestic wiring 4-way junction box – the white circular thing above – and screwed it into a couple of the myriad of screw holes in the back of the red man unit. (These things were clearly made to be customised!) I kept the two transformers rather than trying to run both lights off one transformer because I figured the guys who make these things know what they’re doing far better than a hacker like me…


POW! Light!

Next time in the saga, your host starts modding the electronics, with hilarious consequences.