Yeah you need to use wires to switch around the first two
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I am curious if this design could be coded to show Power/Amperage Draw on a Module.
Would be a nice easy way to get specs for modules we make.
I can’t think how you’d do it with anything much like this circuit. I think measuring current would require sticking a small resistance, say 10R, in series on the rail and measuring the (small) voltage drop across it. Which would be complicated with an Arduino since it wants voltages 0–5V above ground. You’d need to subtract off the power draw of the testing circuit itself which would be non negligible with an Arduino in it, unless the Arduino’s powered separately. You’re also stealing about a millivolt per milliamp from the module, which probably doesn’t matter a lot for testing purposes but might affect the module’s performance.
Or you could just build a stripboard with two connectors and series resistors between them and measure the drop with a multimeter. That’d be a lot simpler. Hm, I should do that.
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I2C INA219 could possibly be used but I am not sure on how much sensetivity you can get. not done too much research. was considering something for the PSU build as we realy have no idea what each module is drawing ( I think I will try and document this if I ever get time. )
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thank you very much , tried paths of each pad and !!! see that now through traces . again a beautiful masterpiece pcb
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yo, what about a current sensor?
https://www.digikey.com/en/articles/the-basics-of-current-sensors
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Woah y’all are using fancy parts!
I was thinking of something more basic, like that:
(The LT1677 can be replaced by any 5V rail-to-rail opamp)
Basically, that would be the same as the INA219, but with negative rail support, and no ADC, obviously.
But yeah in the end it would be easier to find some kind of (positive and negative) current sensor.
This way we could make a device that would test everything: power supply, consumption, and the cables!
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Ordered two Y+B screens from a UK supplier, hopefully arrive before the PCB’s that way
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I mean, yes for sure, but if we were aiming for simple, we wouldn’t do DIY things to begin with, no ?
“Simple” is such a subjective thing, that I don’t want to take it into account when I’m building stuff. “Is it fun”, or “is it interesting/challenging” are better pointers for me to choose a project…
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Absolutely! But this was a tool, not a project, for me…
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The undeniable fact about the simple version is that there’s less to go wrong. For me it’s also aesthetically more appealing, but your mileage may vary.
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Finished up the tester today and it works like a charm. Thanks again!
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UK Ones…
“2020-08-28 18:27:00 Arrival of goods at destination airport”
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I tried this and I’m not sure I did it right. I tested it on working and nonworking modules and got the same “shorted” result. Can you elaborate on the way you set this up?
I realize now that it won’t actually work because it checks between individual pins carrying the same signal. I do still have the short, though 
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Probably a simple software change would make it work — i.e. if it sees the three ground lines shorted but no other problems it could display “Module OK”…? Something like that?
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That would be awesome
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If my other weekend projects flop, I’ll take a look at the code. Could be fun.
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maybe a tester for the cable tester .