Whats in an electronic toothbrush? --Author request - Page 1
Forum section: electronics / beginners

author: battle1
author_rank: Newbie
timestamp: January 29, 2014, 03:44:37 am
content: I am an author looking for information on the materials that are found in a Philips Sonicare Toothbrush.For example, I assume magnets use rare earths, lithium etc in batteries, but am curious about the transistors, resistors and other components. I would be grateful for the help.Thanks!

author: IanB
author_rank: Super Contributor
timestamp: January 29, 2014, 03:51:18 am
content: Why "Philips Sonicare Toothbrush", specifically?Philips is only one brand of toothbrush, and toothbrushes are only one kind of electronic consumer device (like CFLs, televisions, computers and any number of things), all of which share the same basic components in manufacturing.If you want to know about the contents of electronics and electronic waste in general, there must be a ton of material out there which is easily researched.What is it you want to know, exactly, that you can't find by a normal literature search?

author: battle1
author_rank: Newbie
timestamp: January 29, 2014, 04:07:33 am
content: http://www.spiegel.de/international/spiegel/globalization-the-global-toothbrush-a-398229.htmlDiscusses where the components of a sonicare toothbrush come from. Im interested in where the materials themselves come from.I dont want e-waste in general, just perspective on what is -- or very likely -- in some of the components of an elec toothbrush, ideally sonicare.Thanks!

author: IanB
author_rank: Super Contributor
timestamp: January 29, 2014, 04:17:46 am
content: Well, circuit boards use copper. Solder uses tin. Transistors and chips use silicon. Rechargeable batteries use nickel. The raw material for plastic usually comes from crude oil.

author: EEVblog
author_rank: Unknown
timestamp: January 29, 2014, 04:23:07 am
content: If you really want to get down to the finest details, then it can get very complicated. You have to know exactly what each manufacturer is using to construct each each aspect of each part.The major things that mattered where covered in the ROHS directive:http://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: January 29, 2014, 05:23:22 pm
content: Not sure about this model but I took one of these apart and there was a small motor with a cam on the shaft. This causes the "sonic" effect. Just vibrations. So add some steel and probably some aluminum to the list, maybe.Maybe you should donate one to the eevblog for a teardown.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 05:27:27 pm
content: Quote from: IanB on January 29, 2014, 04:17:46 amAlso natural gas -- polypropylene and polyethylene come from propane and ethane, respectively.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: January 29, 2014, 05:33:11 pm
content: Quote from: Phaedrus on January 29, 2014, 05:27:27 pmPretty sure propane is by-product of crude oil refinement.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: January 29, 2014, 05:44:31 pm
content: It can also be extracted from natural gas. My step-dad worked at a plant that turned natural gas into high-grade plastic for prescription bottles and saline bags. Now he works at a refinery that turns crude into a bunch of things including propane, which then turns cows into burgers and occasionally runs taxi cabs.

author: SeanB
author_rank: Super Contributor
timestamp: January 29, 2014, 05:58:31 pm
content: Funny enough I just repurposed an old electric toothbrush. Was worn out but otherwise pretty good. Took it apart ( thanks Dave for that teardown showing how it comes apart) and took the mechanism off the motor. Had lying around a milk frother that had a dead motor, so combined the two by cutting the front off of the toothbrush and using epoxy to fix a washer to cover the hole. Removed the whisk and adaptor from the frother and push fitted it with a tiny drop of epoxy to the motor shaft. Added a brass bushing to provide better support, held in place with 2 part epoxy, and now it works a lot better than before. Cut the charger down to only the potted section and the charge post. Now no longer need 2 AAA cells for 10 cups of froth.

author: IanB
author_rank: Super Contributor
timestamp: January 29, 2014, 08:42:39 pm
content: Quote from: Phaedrus on January 29, 2014, 05:27:27 pmFair enough. I tend to lump all categories of "hydrocarbons you get by drilling holes in the ground" into the same general category. You can even get intermediate stuff out of some wells that is lighter than oil but heavier than gas.Olefins like ethylene and propylene that are used to make polymers are usually obtained from other hydrocarbons by thermal cracking in a furnace. Basically you feed hydrocarbons down a hot tube. The heat breaks the molecules up into small pieces and when the gas cools down again the pieces reassemble into other molecules. You control the feed and the operation of the furnace to obtain the maximum yield of useful molecules. Typical feeds to an ethylene cracker are naphtha or natural gas. Naphtha is a distillation product from refining crude oil.

author: IanB
author_rank: Super Contributor
timestamp: January 29, 2014, 08:46:26 pm
content: Quote from: GiskardReventlov on January 29, 2014, 05:23:22 pmThe Sonicare in particular uses a vibrating magnet rather than a motor. There is magnet on the inner end of the toothbrush shaft and an electromagnet in the handle. The circuit in the handle activates the electromagnet with an AC field and this makes the magnet vibrate in sympathy.