Another defibrillator teardown - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 22, 2012, 03:51:14 pm
content: Includes a special cameo appearance from an upcoming teardown star.

author: firewalker
author_rank: Super Contributor
timestamp: September 22, 2012, 04:44:20 pm
content: Alexander.

author: Bored@Work
author_rank: Super Contributor
timestamp: September 22, 2012, 05:13:03 pm
content: Yep, 8:40 LAMO

author: M. András
author_rank: Super Contributor
timestamp: September 22, 2012, 06:29:26 pm
content: a pick and place machine at home ok alright you work with it, but a bendsaw? and a huge xray machine? ohh man what else do you have there?

author: Zad
author_rank: Super Contributor
timestamp: September 22, 2012, 07:23:35 pm
content: All I'm going to say is... I hope people saw Dr Who this week. Very timely!

author: pickle9000
author_rank: Super Contributor
timestamp: September 22, 2012, 08:09:12 pm
content: Awesome lab.

author: IanB
author_rank: Super Contributor
timestamp: September 22, 2012, 08:19:58 pm
content: I trust you didn't want to use those side cutters again...

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 22, 2012, 09:47:59 pm
content: Quote from: IanB on September 22, 2012, 08:19:58 pmThey've seen worse, and are only a cheapo pair.

author: saturation
author_rank: Super Contributor
timestamp: September 22, 2012, 11:14:57 pm
content: Incredible, Mike, no tear down can now match yours! Are there any legal issues to having x-ray equipment?

author: IanB
author_rank: Super Contributor
timestamp: September 22, 2012, 11:46:55 pm
content: Quote from: saturation on September 22, 2012, 11:14:57 pmGood heavens! Why should there be? Please don't give law makers ideas to make our societies even more Orwellian than they already are. It's bad enough already without imagining ways to make it worse.Go wash your mouth out with soap and wash your brain out with bleach

author: akcoder
author_rank: Contributor
timestamp: September 22, 2012, 11:54:10 pm
content: I met the inventor of the defibrillator about 6 months ago. You couldn't help but know that he invented it because the dude didn't miss an opportunity to tell you that he was the inventor. He was a pretty pompous guy...

author: IanB
author_rank: Super Contributor
timestamp: September 23, 2012, 12:34:13 am
content: Quote from: akcoder on September 22, 2012, 11:54:10 pm...on the other hand, he may simply have lost a bet:Wouldn't it suck to be in that position?

author: amyk
author_rank: Super Contributor
timestamp: September 23, 2012, 09:36:05 am
content: Another awesome teardown!"Alright, let's try another method."*goes to x-ray machine*That was totally unexpected.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 23, 2012, 10:02:42 am
content: Quote from: akcoder on September 22, 2012, 11:54:10 pmI typically find people like this are full of crap - "I was part of the team that worked on some minor detail" turns into "I invented". The other type is those who think they came up with something new (but typically obvious or inevitable) but were "ripped off by The industry" who stole their idea and they just keep whinging about it for the rest of their lives.

author: Psi
author_rank: Super Contributor
timestamp: September 23, 2012, 10:40:00 am
content: Quote from: saturation on September 22, 2012, 11:14:57 pmI dunno about other places but in NZ you have to be trained by the National Radiation Laboratory if yourworkinvolves dealing with x-rays.However, for repairing the electronics, only one person present needs to have this training. Others can do the actual repair work.(Since soldering and PCB repair doesn't involve x-rays directly)Getting the NRL to accept there own rules though, wasn't so easy, as my dad found out.They kept trying to force him to get certified and pay the yearly fees (which cost more than he was getting paid or the occasional repair work needed).The main x-ray technician there was fully certified and was always around during any repairs so dad didn't need to be certified.Eventually they backed down.As far as i know there are no rules for private x-ray usage.Only for paid work.

author: saturation
author_rank: Super Contributor
timestamp: September 23, 2012, 11:57:01 am
content: Why? Its known cancer causing radiation and is considered hazmat, regulated both by federal and state law, at least in the USA. At light doses, its mutagenic, unless of course you enjoy having your new babies with extra or short on toes, eyes, or limbs. But maybe the laws are different elsewhere. One can easily get a China based dental x-ray unit to use for small PCBs, but working it legally is another thing.http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm291539.htmhttp://www.ebay.com/itm/DENTAL-X-RAY-MACHINE-SYSTEM-DIGITAL-PORTABLE-MOBILE-c9-/190548488163?pt=LH_DefaultDomain_0&hash=item2c5d932fe3http://www.state.nj.us/dep/rpp/xrm/index.htmQuote from: IanB on September 22, 2012, 11:46:55 pm

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 23, 2012, 12:16:21 pm
content: kids they like to find small compartment they can fit in thats their playground for "find and hide" or "small/mini house" game. many times i was unaware my kid present in the lab while i enter and work on something, usually they sneak below the bench (i have 4). if i have that machine with that black curtains, turn it on without knowing something is inside, oppps! genetic mutation.

author: Psi
author_rank: Super Contributor
timestamp: September 23, 2012, 12:18:47 pm
content: The xray machines used at the airport for checking your hand luggage don't have massive xray output.The rad meter says ~0.057 mSv when we put it through the Rapiscan 500 machines.For comparisonAn upper or lower GI tract xray is 6-8 mSv and a basic chest x-ray is 0.1mSv.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 23, 2012, 12:28:29 pm
content: but in hospital, its only for a moment right? how about exposure of that low dosage but for an extended amount of time?i also suspect the airport one can be stronger because it has to penetrate some metal bags, no?

author: Psi
author_rank: Super Contributor
timestamp: September 23, 2012, 12:39:32 pm
content: Quote from: Mechatrommer on September 23, 2012, 12:28:29 pmSievert (Sv) is an exposure dosage rating. The rad meter records the total exposure of a trip through the machine.Also inside the machine the actual beam of xrays is <5mm wide.There is a little side scatter though, which is why they put those lead flaps on each end.But yes, if you disabled the conveyer belt and held your hand in the xray beam continuously your radiation dose will keep rising.In fact medial xrays often need to be more powerful because they need to expose an xray film rather than just be picked up by some semiconductors electronically.The usual way they pick up the xrays in a airport machine is just an array of photodiodes covered with a phosphorescent coating that glows when hit by x-rays.They have two types of sensors arrays, both the same except one has more of the coating than the other so it takes higher energy xrays to penetrate through and produce some light the photodiode can detect.This produces two types of data,- The amount of xrays that got through the bag (which gives the image contrast)- The ratio of how many low energy vs high energy xrays made it through the bag (this is used to give color to the image)

author: SeanB
author_rank: Super Contributor
timestamp: September 23, 2012, 12:47:58 pm
content: Airport scanners are a line scanner as the moving belt provides a raster scan on the image. The hospital scanners are a simple point source that exposes a plate of sensitive material ( used to be film but now a sensor array that records the secondary emission from the transmitted radiation) to make the image. Low power in a line is much easier to shield as against a large area flood. Distance the beam travels is under a half metre, as opposed to a hospital where you might have a meter or more of air and body to penetrate. The airport and other scanners are heavy, most is the shielding plates and steel secondary shielding. I would hate to change he belt in one, you have to almost take it apart, and i have enough difficulty with conveyor belting at work as it is.

author: Psi
author_rank: Super Contributor
timestamp: September 23, 2012, 12:51:46 pm
content: I dunno about the others, but with the rapiscan machines changing the belt isn't that bad.You just unzip the old belt, untension the rollers and feed the new belt through then zip it back up and retension.changing/realigning the xray generator however, is quite a long process.New generators have to be powered up gradually in multiple stages with the high voltage being tweaked up and up.Then you have to align the huge heavy oil filled monster to within a fraction of a mm or the beam wont hit the side and top sensor arrays evenly.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 23, 2012, 02:05:37 pm
content: QuoteThere is also a copper filter in front of one of the sensor arrays.Changing the belt on this one looks like it would be a major PITA - had to remove one conveyor end to get it in the van and ended up just cutting the belt on a diagonal as I wasn't intending keeping it running it for long - the duct tape repair is holding OK...BTW anyone know any service passwords for EG&G Linescan 210 machines?

author: G7PSK
author_rank: Super Contributor
timestamp: September 23, 2012, 05:48:50 pm
content: Is that the X ray machine that was on ebay a few weeks back.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 23, 2012, 06:29:43 pm
content: Quote from: G7PSK on September 23, 2012, 05:48:50 pmYes.

author: Magicmushroom666
author_rank: Contributor
timestamp: September 23, 2012, 09:37:16 pm
content: Lol i remember seeing that machine on ebay and dreaming of having a shed big enough to set it up like that! Bravo

author: akcoder
author_rank: Contributor
timestamp: September 24, 2012, 03:52:15 am
content: Quote from: mikeselectricstuff on September 23, 2012, 02:05:37 pmDid you try 12345 or password? You probably wouldn't be surprised at how often those are used as the default