EEVblog 1489 - Mystery Teardown - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: July 28, 2022, 12:00:13 am
content: Teardown of a bizarre looking Banshee 343 Ultrasonic Gas Leak DetectorThumbs up this video and pinned comment if you want to see a countdown timer refit project!Datasheet:https://www.instrumart.com/assets/Net-Safety-Banshee343-datasheet.pdfManual:https://www.instrumart.com/assets/Net-Safety-Banshee343-manual.pdf

author: ace1903
author_rank: Regular Contributor
timestamp: July 28, 2022, 08:13:23 am
content: Can we expect detailed photos onwww.flickr.com/photos/eevblog/site?Want to try to identify that mysterious ADC chip.

author: golden_labels
author_rank: Super Contributor
timestamp: July 29, 2022, 02:23:02 am
content: Soldered-in fuse in that kind of equipment seems fine to me. I assume that, due to safety requirements, the PCBs are not serviceable.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 29, 2022, 06:41:26 am
content: Soldered fuses are not that rare - just using classic 20 mm fuse to be soldered MELF like is a bit odd. Not all fuses (depends on the speed and current) like the soldering and may be damaged, especially with lead free soldering.

author: Barny
author_rank: Frequent Contributor
timestamp: July 29, 2022, 08:15:06 am
content: The custom optocoppler where inEEVblog #1277 - Electric Fence Controller Teardown@05:20And:EEVblog #1292 - $2 Meter vs JVA Electric Fence Controller!@11:00An individual count down thingy in the lab would be funny.But why don't go the full way & use C-cell battery-sticks wrapped in red paper, alarm - beeper for tamper / opening alarm ....On the other hand:You could make an nice alarm-clock out of it using one of the nice RTC chips.

author: Barny
author_rank: Frequent Contributor
timestamp: July 29, 2022, 08:25:56 am
content: Could it be that the rods in the video are only to protect the sensors from impact?Have the rods small holes drilled in them?(In the 0,1 to 1mm region)If thats the case, perhaps the whole thing gets pressurised externally with air or nitrogen with an external pressure line and produce the "real test leak" that way.This would be the cleaning function too.Are the wires to the potted part under the shiny dome NTC or PTC resistors?Perhaps the heater get mounted externally if needed & the wires are only to monitor the heater.Quote from: golden_labels on July 29, 2022, 02:23:02 amI think its due to cost reduction, prevent corrosion on the terminals & prevent the fuse from falling out when the thing gets dropped.

author: tunk
author_rank: Super Contributor
timestamp: July 29, 2022, 09:45:33 am
content: In addition to a countdown timer, maybe you could add a big vibration motor and a speaker?

author: tszaboo
author_rank: Super Contributor
timestamp: July 29, 2022, 11:46:33 am
content: You can see lasered EX marking on those ports, they were ordering special explosion-proof bolts for this.Those sensors can be outside the EX d area, and have thinner metal wall, because there will be limiters in between. They have less power and current and everything so they cannot set the gas on fire. This is the marking "ib" on the type plate, and this is why we have optocouplers and large resistors on that second board.I would correct a few things that you said at the end. This is not really "intrinsic safety", only for the sensors. This is "protection by flameproof enclosure". Meaning that it's not gas-proof, the flammable gas can totally get into the enclosure, and it can explode in case of a failure. The flameproof enclosure can handle this small explosion inside and the protection makes sure that the entire gas plant is not set on fire.That being said I'm not in the design of EX d stuff.Thanks for the teardown.

author: bsdphk
author_rank: Regular Contributor
timestamp: July 29, 2022, 05:21:21 pm
content: Quote from: Barny on July 29, 2022, 08:25:56 amThe studs are so you dont destroy the connector.On one of the early sequences, you can see that the "cup" containing the sensor has matching grooves for the stud, so that you can only get it to fit in the right orientation for the connector.It may even look like the connector is a bajonet style, as the groove in the "cup" is not just a hole but a grove.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 29, 2022, 06:47:11 pm
content: The outer case looks like it has provisions for some air blowing just a cross the sensor from the side. So it really looks like there is the option to have studs with air, but the currently installed ones don't look like they are made for it. Just of the orientation of the connectors smaller pins would be used. The studs have quites some play and would be only a crude first alignment.

author: thm_w
author_rank: Super Contributor
timestamp: July 29, 2022, 08:50:37 pm
content: Quote from: Barny on July 29, 2022, 08:25:56 amThe youtube replies from Mike/Sean/others are relevant:QuoteQuoteQuote

author: golden_labels
author_rank: Super Contributor
timestamp: July 29, 2022, 08:54:09 pm
content: All people coming with the bomb-like ideas: that reminds me of Mark Robber’s glitterbombs. For many reasons Ido notsuggest that to Dave and strongly discourage any of you from doing such things, but just imagine a thief stealing a box with something like that, opening it and seeing the countdown timer.

author: Neutrion
author_rank: Frequent Contributor
timestamp: August 05, 2022, 09:15:35 pm
content: So many of you are suggesting that the case would withstand an explosion by a full filling of perfect air/gas mixture? It is so hard to belive.As for the countdown timer:I would include the text as well: "Fuse nr 1-2-3 OK" and fill the thing with lead of course.And how to get it through the airport sec.? Its easy: "This is a design kitchen timer given to me by that nice guy with a big beard at the entrance as a present."Most important is, to have 1-2 hidden camera guys focusing on the faces of the security guards while saying this, and also to have someone to upload the video later. We don't want to wait for months to watch it.It might could be also hacked to a swiming pool speaker emitting dolphin conversations. Or as a star/galaxy projector. It's so cool, it begs to be repurposed somehow.

author: tszaboo
author_rank: Super Contributor
timestamp: August 06, 2022, 09:46:18 am
content: Quote from: Neutrion on August 05, 2022, 09:15:35 pmIt's been certified to that, otherwise it wouldn't be on the market. And this sort of certification is only given if they are done by a third party, a NoBo, with actual tests performed in the worst case conditions multiple times.Quote

author: Neutrion
author_rank: Frequent Contributor
timestamp: August 06, 2022, 11:25:48 pm
content: Hi!It was not a serious doubt from my side, but the feeling, that I had, that it had to be a bit more thick for that.Dave could also fill it, and explode it in the lab as a nice experiment. (Or at an airport of course.)