Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot

Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by setq on Tuesday June 27, 2017 @02:17PM (#14647809)

Take a look at the output switching on different variants of 555s (there are about 6). This isn't always the case. Not only that if you pull lots of current through them, and 100mA is a lot, then the Pd of the sink transistor is pushed a bit hard. I've let the smoke out of a few over the years working on that assumption.

Good tip: measure voltage between the output pin and gnd or Vcc in both states and then have a think.

Plus when you're not an idiot like I was, a MOSFET is cheaper.

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Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by HeyLaughingBoy on Tuesday June 27, 2017 @02:29PM (#14647929)

Fair point.

I sometimes overestimate the ability of the average electronics hobbyist to properly understand a datasheet.

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Re:Show HN: GreenPiThumb – A Raspberry Pi Gardening Bot by setq on Tuesday June 27, 2017 @02:53PM (#14648147)

I don't think many people read the data sheets to be honest even some of the professional engineers. It's mainly gluing canned circuits together and see if they work or not. This is a little difficult if you didn't start with analogue and work up.

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