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Bonfire of the Sanity 2020

OneTenner

LE
Book Reviewer
Mid 80s
you could still order them from RS components, but then you would have an account, I think it was to stop the cash sales, lots of older cars used them to trigger boot lights, I think I have a few tucked away someplace
I guess the mercury switch was more reliable and easier for unskilled people to use than to fabricate something

we also found some very very old Smoke detectors in Bristol that contained some very radioactive stuff, which rather upset my boss as he had not budgeeted for the disposal costs of the detectors, associated wiring, and the paint scraped off the ceiling above them, plus the masks and paper suits, think they went to the National Physical Laboratory in the end, Radium was the main component, not sure how much, but not the sort of thing to get in the wrong hands
Seems to still be a 'thing' you can buy without any checks

Radium 226 is still used in smoke detectors without any associated clean-up costs after the ten year life expectancy of the source
 
When was that? We were still buying commercially available mercury tilt switches and other IED components in 2008.

There’s no point bannng the sale of such items or pointlessly accounting for them, switches are easily improvised - tilt switch just requires a bit of plastic tubing, ballbearing and hot glue, pull switch requires clothes pegs and drawing pins and pressure or pressure release could be the door switch of a car courtesy light.
2 years ago I passed through Heathrow with 4 Asian lads. in our luggage we had batteries, wire, radio control gear and a variety of commercial and improvised tilt switches. No drama except that we arrived in Abu Dhabi, our luggage had gone to Qatar...
 
Mid 80s
you could still order them from RS components, but then you would have an account, I think it was to stop the cash sales, lots of older cars used them to trigger boot lights, I think I have a few tucked away someplace
I guess the mercury switch was more reliable and easier for unskilled people to use than to fabricate something

I was duty terrorist in ’93 and frequented tandy and radio shack. Many IED components were available - mercury tilt switches, LDRs, SCRs, 555 timers, microswitches. Only limited by your imagination.

Stick a fluorescent screen in front of a LDR, it makes an excellent x-ray switch.
 
I was duty terrorist in ’93 and frequented tandy and radio shack. Many IED components were available - mercury tilt switches, LDRs, SCRs, 555 timers, microswitches. Only limited by your imagination.

Stick a fluorescent screen in front of a LDR, it makes an excellent x-ray switch.

Thread drift, but I was gobsmacked to stumble across this website, as I had no idea all of this stuff was available to gen public?

 

RABC

LE
I was duty terrorist in ’93 and frequented tandy and radio shack. Many IED components were available - mercury tilt switches, LDRs, SCRs, 555 timers, microswitches. Only limited by your imagination.

Stick a fluorescent screen in front of a LDR, it makes an excellent x-ray switch.

555 timers. Do they still sell them ?

Anyway, I digress, our dog is a collie and she listens and thinks too much. Thinks nothing of chasing a petrol lawn mower, but fireworks petrify her.
 

wheel

LE
I was duty terrorist in ’93 and frequented tandy and radio shack. Many IED components were available - mercury tilt switches, LDRs, SCRs, 555 timers, microswitches. Only limited by your imagination.

Stick a fluorescent screen in front of a LDR, it makes an excellent x-ray switch.
@Joshua Slocum is known to come out with the the occasional tall story.
 
@Joshua Slocum is known to come out with the the occasional tall story.

I don’t think he’s telling tall stories, im just disputing some things. Components such as memo park timers were illegal to possess in NI, but were still readily available in GB.
 
555 timers. Do they still sell them ?

Anyway, I digress, our dog is a collie and she listens and thinks too much. Thinks nothing of chasing a petrol lawn mower, but fireworks petrify her.
A 555 timer chip will cost you about 30p... The mechanical Parkway (?) timers which were popular with the players are pretty rare, and a good one will cost you $40 or so.
 
I don’t think he’s telling tall stories, im just disputing some things. Components such as memo park timers were illegal to possess in NI, but were still readily available in GB.
ISTR that the U.K. bought the Swiss company to end production? I have one in the shed somewhere, still works fine after 45 years...
 

TamH70

MIA
Walking back from Sainsbury's in Pollok/Darnley/Not Sure tonight, I passed through some housing schemes in which they were re-enacting First Somme. I was too tired to do more than a bit of mild yelling in response.
 

NSP

LE
Jesus H. Christ! Worse year ever around here. It sounds like a bad night in Berlin circa 1944 outside at the moment.

FFS...
 

philc

LE
Jesus H. Christ! Worse year ever around here. It sounds like a bad night in Berlin circa 1944 outside at the moment.

FFS...

Showing you age, its more Beirut on a Saturday night, yes I was their man. Mostly in a basement bar watching Football.
 
Radium 226 is still used in smoke detectors without any associated clean-up costs after the ten year life expectancy of the source
I thought modern smoke detectors used Americium? Still dangerous if intentionally misused of course.
 

Joshua Slocum

LE
Book Reviewer
I thought modern smoke detectors used Americium? Still dangerous if intentionally misused of course.
They do
Amercium 241 used since the 1963 into the early 70s

However these only operated on 24v and 50v rail systems ie the early electronic control panels
Before this time most fire alarms were either 240v 3 wire mains operated or 24v 3 wire systems using drop flag indicators
Ie electro mechanical, these ayatems were initiated by either call points where you broke the glass or bimetallic strip drop arm heat detectors

Several American companies manufactured 240v powered smoke detectors with an on board power supply that would trigger the system via a relay across the 3 wire circuit
They used radium 226 as a source and were often fitted in lift shafts and service voids
 

OneTenner

LE
Book Reviewer
I thought modern smoke detectors used Americium? Still dangerous if intentionally misused of course.
Yer, they do - I had to get some kit moved by air a few years ago containing Radium 226, I made the assumption it was ionisation smoke detectors - looking back through emails it turns out it was medical kit for part of the same project.
 
Yer, they do - I had to get some kit moved by air a few years ago containing Radium 226, I made the assumption it was ionisation smoke detectors - looking back through emails it turns out it was medical kit for part of the same project.
I thought so. I haven't had to deal with Physics for years but I have a vague memory of Americium being preferred as it is only an alpha emitter so if you've got a few centimetres of air between you and the detector you're safe. Radium emits alpha, beta and gamma so is much nastier to have lying around.
 

TamH70

MIA
I thought so. I haven't had to deal with Physics for years but I have a vague memory of Americium being preferred as it is only an alpha emitter so if you've got a few centimetres of air between you and the detector you're safe. Radium emits alpha, beta and gamma so is much nastier to have lying around.

Yeah, just ask M'sieur and Madame Curie - if you can get passed the lead-lined coffin at the Pantheon in Paris.
 
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