Product design for test & installation - Page 1
Forum section: electronics / projects

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 26, 2015, 11:33:05 pm
content: A look at one of my LED control products, showing design features aimed at helping with installation and test

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: March 27, 2015, 08:27:50 am
content: Very informative videojust one thing about testing with led, i designed once a board ( a small AC voltmeter with 3 7-seg display) when powered up the software go to display test where he just count from 000 to 999 with 111 step just to see if there is any problem. what happen is after testing few board that work correctly the operator miss faulty one, as someone explained to me they had visual memory thing so they don't see the fault any more. same thing happened with a led board ( 8 power rgb led ) but here LED are so bright that after testing few one operator can't tell the difference if the led is really on or it's a perpetual light on their eyeswell that was stupid thing to handle they just covered led with some translucent material. the point is, even if the test is pretty much easy, observing a led lighting sequence to valid a product is not that evident.an other observation is the little adapter board with plug-in phoenix contact connector, is there any reason why they are mounted face to face and not back to back , why ask , is that i designed once a board with that same configuration and the cable of curse with insulated cable ferrule, and after all cable being placed unplugging or plugging a cable was not that easy.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 27, 2015, 10:33:43 am
content: Quote from: hamdi.tn on March 27, 2015, 08:27:50 amThis is where you need to consider possible faults. counting 000 to 999 is pointless - all you need to do is test all segments, so just 888 would do. If you also wanted to check for sorts, maybe a couple of other patterns, but ten patterns would be useless, and make errors harder to spotQuoteIt's so the wires come out the centre, keping the pairs close togther and the buttons accessible.

author: HP-ILnerd
author_rank: Frequent Contributor
timestamp: March 27, 2015, 01:26:02 pm
content: Terrific video, Mike! As usual, I learned something.

author: Rufus
author_rank: Super Contributor
timestamp: March 27, 2015, 03:22:19 pm
content: Quote from: mikeselectricstuff on March 27, 2015, 10:33:43 amI have used patterns of one of each segment lit in turn, (spread across digits to check segment and digit drive shorts) followed by all segments lit on all digits to check all segments function and maximum load. Not hard to spot that either one segment is lit or all of them are.

author: rollatorwieltje
author_rank: Unknown
timestamp: March 27, 2015, 08:00:49 pm
content: Do you have any problems with those 4 pin Phoenix connectors? At work we use those often, but I find it really annoying that the cable is not mechanically fixed, putting all the stress on the copper itself. This often results in cables that break near the connector. The wires are terminated with a crimped ferrule. Either the copper breaks near the ferrule entrance or the ferrule just cracks (probably overtightened the screw, which is just too easy). The ones where you push in the ferrule without screws seem a bit better (probably because they allow a little movement?).

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 27, 2015, 08:05:33 pm
content: Quote from: rollatorwieltje on March 27, 2015, 08:00:49 pmNo, but once installed they don't get moved much. Bootlace ferrules help.