Continuity tester with glitch capture - Page 1
Forum section: electronics / general

author: hammil
author_rank: Regular Contributor
timestamp: March 30, 2013, 01:06:50 am
content: Hey allAfter my first foray into reverse engineering, I found that a decent continuity tester is completely invaluable. The trouble is, they only tend to come with high-end multimeters.I reasoned that the circuit wouldn't be too complex or expensive to make... So with that, I thought I would create one.Here's a simulation of the concept:http://bit.ly/14tB0osI guess I was trying to come up with the 'ultimate' continuity tester - adjustable sensitivity, adjustable pulse duration, /very/ sensitive glitch capture, and a voltage low enough that it wouldn't turn on even the finest Schottkey diodes.The schematic is attached to this postPCB layout:http://uploads.oshpark.com/uploads/project/top_image/VjPcSEKu/i.pnghttp://uploads.oshpark.com/uploads/project/bottom_image/VjPcSEKu/i.png( I can't seem to get logos to flip properly in KiCad.. )The components are all generic and as labelled, with the exception of the buzzer (http://uk.farnell.com/projects-unlimited/ai-1223-twt-5v-r/audible-signal/dp/1653527) the connectors (http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1698984&MER=baynote-1698984-pr), and the comparators (http://uk.farnell.com/stmicroelectronics/ts393idt/comparator-dual-micropwr-8soic/dp/1750194, although an LM393 could be used without any problems ).Power consumption should be in the microamps while not buzzing, so I didn't bother with a switch.I'm thinking I might make a little line of devices like these... A low-cost JFET probe is in the pipelines, as is a redesign of the differential probe I talked about before.

author: ivan747
author_rank: Super Contributor
timestamp: April 06, 2013, 01:04:25 am
content: Neat! But I think the switch is really necessary. I like these sort of little circuit boxes. Now we have the µCurrent, the 4-wire resistance adapter Dave got in the mail and this continuity tester .What kind of pots are you going to use?I am planning to make a True RMS to DC converter box with this form factor.

author: timofonic
author_rank: Frequent Contributor
timestamp: June 25, 2015, 07:18:43 pm
content: Necroposting...Are there any news about it? My shitty & old DMM has a very bad continuity tester.Some.circuits...http://archive.siliconchip.com.au/cms/A_30755/article.htmlhttp://www.electro-tech-online.com/articles/programmable-continuity-tester-to-build.712/https://github.com/valencra/Continuity-Testerhttp://electronicdesign.com/analog/ultimate-continuity-tester-hides-many-tricks-its-sleevehttp://www.electroschematics.com/9232/continuity-tester-differentiates-resistance/http://www.brighthubengineering.com/diy-electronics-devices/67224-build-yourself-a-simple-continuity-tester/http://www.talkingelectronics.com/html/ContinuityTester.htmlhttp://www.eeweb.com/blog/extreme_circuits/continuity-tester-circuit-diagram

author: Marco
author_rank: Super Contributor
timestamp: June 28, 2015, 04:45:09 am
content: None of these seem able to catch discontinuity glitches.AFAICS a continuity tester should work like this :- If short in last X seconds and not beeping for last X seconds then toggle beep on- If open in last X seconds and beeping for last X seconds then toggle beep offCan't do this with a simple Schmitt, need some logic.

author: timofonic
author_rank: Frequent Contributor
timestamp: July 02, 2015, 04:31:56 pm
content: Quote from: Marco on June 28, 2015, 04:45:09 amI see.What kind of logic? Secuential?

author: ivan747
author_rank: Super Contributor
timestamp: July 06, 2015, 03:47:34 am
content: I bet you you can do it with an op amp, an RC charge circuit and a comparator. Op amp can even be optional.

author: Marco
author_rank: Super Contributor
timestamp: July 06, 2015, 02:40:19 pm
content: Quote from: ivan747 on July 06, 2015, 03:47:34 amA simple latching continuity tester sure, but as I said ... ideally it should be able to catch discontinuity glitches as well.If there is a break while it's latched beeping it should remember that break and latch silence after the reset period, the circuit needs memory.

author: timofonic
author_rank: Frequent Contributor
timestamp: July 07, 2015, 07:54:37 am
content: I found another circuit here...https://www.eevblog.com/forum/index.php?topic=45769.0Memory = flipflop or microcontroller?

author: Marco
author_rank: Super Contributor
timestamp: July 07, 2015, 12:48:06 pm
content: In this day and age, probably a micro ... even if it will only be a 10 line program.

author: kripton2035
author_rank: Super Contributor
timestamp: July 09, 2015, 06:50:08 pm
content: a list of some here :http://kripton2035.free.fr/continuity-repos.html

author: timofonic
author_rank: Frequent Contributor
timestamp: July 09, 2015, 10:35:50 pm
content: Quote from: kripton2035 on July 09, 2015, 06:50:08 pmThanks! Too much options. What's the best? I got confused! :O

author: kripton2035
author_rank: Super Contributor
timestamp: July 10, 2015, 06:59:30 am
content: I made the cypress lockin milliohmmeter and I like it.I'm now extending (trying to) the range to 100 ohms or so, trying to change the measuring frequency,and adding a speaker to hear the continuity... I made it on a veroboard and the last digit is really stable !I also like the elm-chan one, and the elv kd1 (that could for sure be simplified)

author: timofonic
author_rank: Frequent Contributor
timestamp: July 16, 2015, 11:20:21 am
content: Quote from: kripton2035 on July 10, 2015, 06:59:30 amPlease post your modifications if you want. It could be greatly appreciated

author: flashdrive71
author_rank: Newbie
timestamp: March 07, 2019, 01:13:37 pm
content: because you listed url's for different websites did you ever see article for Ultimate continuity tester hides many tricks up it's sleeve 10-2-2008 .by louis vlemincq. I looking for the fig.1 and fig.2 schematics from Electronic Design Magazine they are missing on article on website and Electronic Design does not have them in their data base. If you have them can you email them to me. It was great article but need to see what the schematics looked like.

author: Gyro
author_rank: Super Contributor
timestamp: March 07, 2019, 01:21:02 pm
content: ... and that's why I never get around to throwing anything away!P.S. Irrc, fig.2 just showed how it worked to identify wrongly phased transformer windings.https://www.electronicdesign.com/analog/ultimate-continuity-tester-hides-many-tricks-its-sleeve