Faucet light - Page 1
Forum section: electronics / beginners

author: kt315
author_rank: Regular Contributor
timestamp: April 18, 2013, 12:58:27 am
content: I came across one of these on the ebay:http://www.ebay.ca/itm/230867280850?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648#ht_3115wt_1378Any ideas how it is powered?

author: IanB
author_rank: Super Contributor
timestamp: April 18, 2013, 01:02:48 am
content: It says "no batteries required" so it probably uses a small turbine that spins as the water flows. It only needs to generate a few mA to power an LED.

author: FenderBender
author_rank: Super Contributor
timestamp: April 18, 2013, 01:11:32 am
content: That's pretty good for US $3...

author: David_AVD
author_rank: Super Contributor
timestamp: April 18, 2013, 01:13:07 am
content: I bought one to see how it worked. There is a battery - the packaging lied.Basically a pair of button cells, an LED and a (water) pressure switch.

author: c4757p
author_rank: Super Contributor
timestamp: April 18, 2013, 01:15:38 am
content: Quote from: David_AVD on April 18, 2013, 01:13:07 amShocker.

author: FenderBender
author_rank: Super Contributor
timestamp: April 18, 2013, 01:15:51 am
content: I figured as much. Not that a little dc motor and a turbine and some diodes costs that much, but for $3 idk bout that.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 18, 2013, 01:16:33 am
content: And seems like it has a temperature sensor, since the color changes based on the water temperature.David.

author: David_AVD
author_rank: Super Contributor
timestamp: April 18, 2013, 01:18:29 am
content: I don't recall if the one I got was colour changing (with water temperature) to be honest. It could have been, but I do recall the coin cells.

author: IanB
author_rank: Super Contributor
timestamp: April 18, 2013, 01:45:42 am
content: Quote from: David_AVD on April 18, 2013, 01:13:07 amAh, makes sense. A bit like those (fake) magnetic "shake to operate" torches then, that also have a coin cell inside them...

author: FenderBender
author_rank: Super Contributor
timestamp: April 18, 2013, 01:46:24 am
content: Wait no I thought he meant, just a switch that turns it on, not powering it.

author: IanB
author_rank: Super Contributor
timestamp: April 18, 2013, 02:14:45 am
content: Quote from: FenderBender on April 18, 2013, 01:46:24 amYeah, I know. They used to sell those torches that pretended to have a generator inside them, but all along they just had a battery and a switch that activated when you would shake them. All seemed fine for a year, until the battery expired and they stopped working.

author: David_AVD
author_rank: Super Contributor
timestamp: April 18, 2013, 02:19:10 am
content: You mean somebody was making and selling something that was a sham? Say it ain't so!

author: kt315
author_rank: Regular Contributor
timestamp: April 18, 2013, 03:10:08 am
content: Yeah, I was wondering where does it actually take power from. But I guess the phrase "does not require battery" can be a bit misleading.

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: April 18, 2013, 05:29:32 am
content: I got one of these and it is powered by a turbine. You can hear the buzz as it turns.It has three colors, rather bizarrely arranged. Cold water results in green light, warm water in blue and hot in red. It does take a second or two to change with temperature. Seems kind of gimacky, but it quickly becomes natural to check the colors before washing hands with cold water or getting a scald with too hot of water.

author: David_AVD
author_rank: Super Contributor
timestamp: April 18, 2013, 07:42:53 am
content: There must be different varieties of them. I think I got mine from an AliExpress seller.

author: Hydrawerk
author_rank: Super Contributor
timestamp: April 18, 2013, 01:05:12 pm
content: Quote from: IanB on April 18, 2013, 01:45:42 amEsactly. I got one in about 2002 and it was crap. In 2003 I got this rotating mobile phone charger with a white LED. It's been produced for a long time. I put a 1 Farad 5V capacitor there. This is now my real hand powered torch.

author: daveshah
author_rank: Unknown
timestamp: April 18, 2013, 03:42:08 pm
content: I once had a 'solar powered' torch that had a solar panel and diode (to prevent the battery from discharging through the panel) connected in parallel with an ordinary non-rechargeable CR2032. When I took it apart, the battery had an open circuit voltage over 5V! It dropped to almost nothing under load though.

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 18, 2013, 04:43:59 pm
content: Quote from: David_AVD on April 18, 2013, 01:13:07 amThey Lied, surely not, advertisers don't lie do they.

author: amyk
author_rank: Super Contributor
timestamp: April 19, 2013, 10:59:29 am
content: This is something I'd like to see a teardown of (one with generator preferable, but "fake" one would be fine too.)