We’re not entirely sure where the lightbulb-idea concept came from, but it’s a cultural touchstone rapidly becoming outmoded by the prevalence of compact fluorescent and LED lighting. Despite this, [Alex Glow] and [Moheeb Zara] whipped up the Prometheus Lamp to let you experience it for real.
The build starts with a glass lightbulb souvenir from the Neon Museum in Las Vegas. Inside, a TinyLily Mini microcontroller board is tasked with talking to an accelerometer to detect movement. When the lightbulb is picked up and oriented in the vertical axis, it lights up a NeoPixel LED, glowing to indicate that you’ve just had a remarkable idea! It’s all powered off a single CR2032 coin cell, thanks to the low voltage requirements of the modern TinyLily components.
It’s a build that serves as a good way to learn about accelerometers, and it makes a fun desk toy, too. We’ve seen some other projects go by the name “Prometheus”, too — like a wrist mounted flame thrower. How’s that for variety?
I just want it to say “Light bulb!” in Gru’s voice.
Why not just use a tilt switch to turn it on when oriented in the vertical axis? You obviate the need for all the hardware and have zero power use when not activated.
One obvious feature is that with an accelerometer you can adjust the angle that counts as up. Or even have it light up on any movement, and then stay lit if up.
You could also add an auto-off timer, in case you’re mounting it on something.
You’re also ready to add remote activation if you want.
You could, but once adjusted you never have to do that again, so it’s a pointless feature. A tilt switch can also be built with different angles of activation.
The rest of your list has nothing to do with the accelerometer part, and can just as well be implemented with a physical on switch.
One obvious downside of the accelerometer is current consumption, this runs on a coin cell.
Any modern cheap but decent pedometer uses an always-on accelerometer, and last for more than a year on a smaller coin cell than the one used here. Heck, my phone has an always-on accelerometer plus a whole lot of other things going on at the same time, and it draws less current than this does.
No, it’s not the accelerometer. The issue is between the keyboard and the chair. Specifically, the lack of interest in making even the slightest nod to current consumption issues. In lieu of time spent chasing clicks, no doubt.
Good points. Of course he ought to make use of the 328p power saving features like you describe below.
I meant the tilt switch could literally be in series with the battery and LED. But an accelerometer requires the microcontroller.
Not to mention the lily mini is pretty expensive.
I couldn’t find anything in the linked article about current consumption. The arduino sketch they include doesn’t appear to use any low power techniques at all – no reduced clock rate, no turning off unused parts (like ADC), no sleep modes, no disabling brownout detector, no disabling watchdog… I’m guessing that circuit continuously sucks 10-20 mA out of that poor CR2032. They’ll be lucky to get a couple of hours of runtime out of it at that rate — A CR2032 is good for 200-250 mAh, but only at a 2 mA rate.
The decisions we made on this project were based on what we had on hand. It was just a random late night hack for funsies. So yea we could have used a tilt switch and employed some power saving techniques, but that wasn’t really the point.