Bike light design
Sep. 20th, 2017 08:12 pmFor a while I had the impression my back bike light remembered whether it was on or not when you removed and replaced the battery. And I wondered how that worked. A push-button that moved a physical toggle between three positions seemed implausible. But so did some tiny bit of persistent memory. My best guess is that there was a capacitor which held charge for a short time.
Now, I think I was completely wrong. I think that when you put the battery in, it *always* comes on. I just assumed that it would usually be off and didn't actually check that was true. So I got the impression it was lit *sometimes* on battery-connect, and connected that to the state it had before the battery was removed.
Wow, it's really easy to manufacture evidence for something even when you think you're avoiding that.
Presumably the "power on lit" is so that loose connections don't turn it off. OTOH, that would mean if it has a loose connection when it's being carried about, it might come on and drain the battery. Or maybe no-one thought about it and this just happened to be the case. Or maybe there's a regulation? I don't know.
Now, I think I was completely wrong. I think that when you put the battery in, it *always* comes on. I just assumed that it would usually be off and didn't actually check that was true. So I got the impression it was lit *sometimes* on battery-connect, and connected that to the state it had before the battery was removed.
Wow, it's really easy to manufacture evidence for something even when you think you're avoiding that.
Presumably the "power on lit" is so that loose connections don't turn it off. OTOH, that would mean if it has a loose connection when it's being carried about, it might come on and drain the battery. Or maybe no-one thought about it and this just happened to be the case. Or maybe there's a regulation? I don't know.