Hi!
My "cool idea" is based on the video on Youtube:
It is possible to "bump up the voltage" by pressing the piezo disk continuously. The electricity is saved in capacitor. So i thought that maybe it is possible to make an battery-free energy source to Arduino by using larger capacitor. Arduino Duemilanove needs at least 5 V to operate. I have heard about "Joule Thief," by which it is possible to make for example 3V to 6V. As my current project involves measuring the temperature, I need the arduino to work only some of seconds
Well yes if you had a large capacitor, large piezo device and something moving it constantly.
It will produce hardly any current so it unlikely you could get it to work very well. The arduino would also have to be off most of the time and you would pysically need to turn it on to have it measure a temperature, unless you have something generating power with the peizo constantly.
You can get the arduino power down to about 5uA when in sleep mode but with the power that a peizo can generate, I doubt it would last very long. It uses a lot more power when on (more like 5mA), then you would need to power some kind of storage device presumably.
You would be better off using a cheap solar panel out of one of those 3 LED torches you can but for about £1 off ebay... Or just a better solar panel and ni-mh battery still wouldn't set you back more than about £10 and would be able to power it for so much longer...
you are probably right. But still i think that piezo elements are very cool. I was thinking to mount these in my shoe, and when i walk, it generates electricity to light up bright led and so i can see in the dark when i have no torch with me I connected a small led to a piezo buzzer from an old clock and it really works - when i tap it with my finger, the led flicks, i haven't tryed with the capacitor.
I just found a snowboard which cover works as display and is powered by piezo.
There's a university researcher (I believe in the U.S.) who's made fairly good progress with that idea. Ultimately, he wants to be able to power things like mobile phones and Shuffles from "shoe electricity". Unfortunately, I can't remember any of the names, places, or links.
alternative power sources are definitely an interesting field. In my country there was an exhibition, where people were able to turn on led by just holding it with both hands.
Speaking about solar energy - last year i was in the army and when we had a camp in the woods, i charged my cellphone with a small solar panel which was integrated to rechargeable battery. Im very interested in such energy sources. At the army i also planned to buy a shakeable flashlight.
In instructables.com - there was a tutorial how to build shakeable light into tic-tac box.
Unfortunately these are not very bright. I still like my old 3W LED torch.
I just found a snowboard which cover works as display and is powered by piezo.
Yeah, a concept though...
I think solar is still the best way to go although the self-drive watches work well. My father has one still going from his dad!
Very expensive in those days though.
i just connected my 5V 800mAh solar charger to Arduino and it started to work. Unfortunately, as i have connected temperature sensor + 2 leds to it, it doesn't show the right temperature.
with 5v solar charger: 32 degrees
with 9v battey: 24 degrees (which is right)
I haven't seen any "self-drive watches" in our shops. Very interesting things...
The "self drive" watches are an old idea for winding a standard mechanical movement wristwatch. They were usually referred to as 'self winding'. It was an entirely mechanical system with a rotating bob weight that moved around as the wearer moved his arm thus winding the mechanism. Not really suitable for an electrical device.
My wife has a quartz watch that (sort of) works on the auto-wind idea. There's a very tiny generator connected to a pendulum. As she swings her arm, the pendulum rocks back and forth, moving the generator. I believe it uses a capacitor to store the generated electricity. It has never worked very well. But it's a first generation so that isn't too surprising.
USA has always been the leading electronics producer. Most innovative gadgets come from there. At least in my opinion. You, Coding Badly, are very lucky to live in such country. When I want to buy something from US, the transportation costs + taxes + money transfer fees etc. will make me pay almost double price of the product.
USA has always been the leading electronics producer.
In the case of my wife's watch, the credit goes to the Japanese.
You, Coding Badly, are very lucky to live in such country.
When it comes to buying things I want or need, I strongly agree!
When I want to buy something from US, the transportation costs + taxes + money transfer fees etc. will make me pay almost double price of the product.
Yikes! That's painful! I don't say the following to make you feel bad but to acknowledge just how lucky I am: A typical order from Mouser takes two-to-three days to get to my house and the shipping is $3 to $6. DigiKey takes just a day more.
yeah, that makes me check different places to get the best price. Actually I haven't purchased anything from US, but my father bought some telescope parts and the extra payment was as much as the parts cost. So it must be very rare and hard-to-get thing when i'm going to order it from US. In China there are places, that ship worldwide free...One quite safe place to order gadgets is http://www.dealextreme.com. my friend bought a green laser pointer from there, but unfortunately like almost all cheap things from China, it got broken. I recently found an interesting thing from there: http://www.dealextreme.com/search.dx/search.tritium - it's a keychain with tritium gas inside. It's told to glow continuously at least 10 years. Also the radiation of these are claimed not to be danger. However i'd like to see a person who'd like to carry radioactive keychain 10 years in his/her pocket. Ofcourse if not aware of the health risk then person just dont know about it. I guess even if i order it, the customs wont let it in, because of "possible terrorist attack".
i just connected my 5V 800mAh solar charger to Arduino and it started to work. Unfortunately, as i have connected temperature sensor + 2 leds to it, it doesn't show the right temperature.
with 5v solar charger: 32 degrees
with 9v battey: 24 degrees (which is right)
just guessing but if you're feeding the solar 5v into the same place as the 9v battery your arduino will see less than 5v so the temp will read high. Maybe if your solar setup delivers 5v reliably you can feed it directly to the arduino and bypass its regulator.
I recently found an interesting thing from there: http://www.dealextreme.com/search.dx/search.tritium - it's a keychain with tritium gas inside. It's told to glow continuously at least 10 years. Also the radiation of these are claimed not to be danger. However i'd like to see a person who'd like to carry radioactive keychain 10 years in his/her pocket. Ofcourse if not aware of the health risk then person just dont know about it. I guess even if i order it, the customs wont let it in, because of "possible terrorist attack".
The old BT Trimphone had tritium in the dial to make it glow.
When they were recalled, there were strict limits on how many they could store in one place, because of the radiation.
The luminous dial contained the mildly radioactive element tritium,
I once saw a documentary about tritium on Discovery channel. The scientists believed that tritium is good for health and so made some cosmetics like creams that everyone used to spread all over their body.
I'm trying to make a small led flashlight using piezo disk.
I'm going to use ultra bright led (5V / 25 mA).
Which electrolytic capacitor should i use (haven't bought any yet)?
On the video it was used 10 uF capacitor. I don't understand what do these volts mean.... can i use a 50 V capacitor or is it better to use smaller 6.3V capacitor for piezo disk..
