Scott Rowland 🏳️🌈
Technology ConnectionsI have a new video.
I don't know how exactly I thought these things worked before I looked it up, but it sure wasn't anything close to how they actually work.
Semitones@TechConnectify Thanks for the video! I use these things (photoresistors) as part of a DIY apparatus to teach kids about Water Quality Monitoring. :) They build a detector that reacts to the resistance from the photoresistor, and once that works they swap it out with a conductivity cell to measure water.
Primm@TechConnectify just as i was binging lots of your other videos - perfect!!
Max von Webel@TechConnectify JUST TWENTY MINUTES? WHAT DO YOU THINK WHAT I AM, A PERSON WITH STUFF GOING ON IN MY LIFE?
Michal Chodzikiewicz@343max @TechConnectify oh gawd, I am I father of a 2yo, so I guess I have planty things to do but I relate to this anyway...
Miss Aemilia🎀@TechConnectify I appreciate your foresight into the demand for "Hysteresis".
Thankyou. It is an excellent word that I revel in all opportunities that it is relevant. Kinda like "verisimilitude".
James 
@TechConnectify great video just watched it.
I also have no idea how I thought they worked but I don’t think I would have guessed reality either!
Rev. GothAlice@james @TechConnectify Mild spoiler if you’ve ever worked with civic engineering departments: the sensor needs to be free of debris to operate. Melting snow off as a side-effect is beneficial.
ʎllnɔs@TechConnectify flashing back to when I was a kid and we’d shimmy up the lamp posts and shine a flashlight into the sensor to turn off the light so we could play flashlight tag. Surprisingly (to we kids) the lights would stay off for a long time after they were flashed.
Freyja Domville
iaian7@TechConnectify Wow, definitely not what I expected! And the conclusion about making creative connections was fantastic. 👌
Mani1989Loved the hysteresis joke
J.P. Stewart@TechConnectify Our house came with a photoelectric switch controlling the outdoor fixtures (no manual override).
That switch failed several times and I finally replaced it with a zwave relay & smartthings (plus some smarts around guaranteeing that it’s on either in darkness or during evening hours). This also allows for an easy override now as well.
Now I understand precisely why it always failed with the lights on all of the time. :)
@jpsays True story, what inspired this video was that my new home was built with one of these for controlling the garage lights. My neighbor has a malfunctioning one and their lights come on and off repeatedly during the day and stay off at night.
I was trying to come up with a failure mode that would result in that behavior, then realized I don't understand how they actually work. So I looked it up, was very surprised, and boom. Video!
I still have no idea why theirs behaves like that, though
@jpsays My only guess is that it's wired to itself somehow. So the heater comes on only during the day, but then it turns itself off once its hot.
Not sure if you could miswire it that way during installation or if it's internally buggered up
danielfalk@TechConnectify
That is fascinating and you're right, it is very Rube Goldbergian! I don't understand how you manage to keep coming up with interesting video subjects like this
That is fascinating and you're right, it is very Rube Goldbergian! I don't understand how you manage to keep coming up with interesting video subjects like this
Alessandro@TechConnectify very neat! The bit about the lights turning on after a blackout was a fun piece of trivia too.
grant 
@TechConnectify ahh so that's why you needed that sketchy power stuff a couple days ago...
@grant you actually haven't seen the results of that test! It went... very weirdly. I'll probably talk about it on Connextras, though.
eater@TechConnectify I'm a bit confused about the focus on micro-controllers, because at the point you're stepping power down to micro-controller level, wouldn't the thyristor method work, and be leagues better?
@eater The thyristor method on its own isn't binary and doesn't have any hysteresis.
Now, there definitely are ways to get those things without moving to microcontrollers and software. But it would be more complex than simply hooking the nightlight circuit into a relay.
Full disclosure, though, that was mostly just for a cheap joke
makemake@TechConnectify I really enjoyed this one! Definitely one of your best videos to date
J. Peterson@TechConnectify As I software engineer I concur that juicing resistors out of spec to cook a thermostat could indeed be more reliable a microprocessor running code.
@TechConnectify OK even as a power systems engineer that is still a huge TIL for me. I now also want to see how cold it would need to turn the lights on.
Pat Squall Hey@TechConnectify I honestly thought it was a solar cell attached to a relay with some kind of timer to keep it from oscillating on/off in weird lighting conditions. Way simpler than expected.
@TechConnectify I'm a little curious about how ambient temperature impacts these. Obviously it works out ok because my street lights behave reasonably in Winter. I'm just curious about the possibility that these are tuned for different climates.