which type of connection will yield more output from peizodiscs

what about the energy harvesting chips from LTech? they sent me a kit with a disc on and some other bits, it's a pretty neat kit. I am waiting to get hold of the weurth one . With the LT one It's a 25mm diameter disc, tapping it with a pencil and it charges a small smd bank of caps, this then drives a energy micro geko board with LCD. so far its been pretty good. I will do a vid when I get the weurth one tho, that also has the Geko dev board in it
 
okay i will build one right away

can i use a Mic 9u wo4m bridge rectifier ... it has four legs ..so i concluded that it might be a full wave

also,
did you mean i have to connect each peizo with a full wave diode and then take the output from these diodes in parallel
and feed it to the capacitor and test the current
 
can you send me more details about the board you got from Lineartech
also how does it work , did you try implementing it non something ??
 
there are loads of dev boards from them, I have the multi source board DC2042a.
Start here http://cds.linear.com/docs/en/datasheet/35881fa.pdf
then goto there site, there is loads and loads of info.
Then look at weurth electronika there is a big kit they make in a red box, EEVblog has done a video about it.
I havnt used the kit, my dad has. all I am allowed to tell you is, your using the wrong type of generator, there is a flexible strip one, its designed to flex and bend, the discs are not as good.
The parts are expensive but without them your flogging a dead horse!
Please go look at Linear technology there is a great deal of information on ENERGY HARVESTING.
I would like to help you more, and tell you about what my dad is working on, but I cant, Yes with the right parts its possible to harvest small amounts and use them, but you will need to do alot of reading. also think about storing the energy, and maybe some way to have more than one source.
For your application, I think your on the wrong track, you are using the wrong kind of disk.
 
I cannot find spec's on your bridge rectifiers. Their leakage current might be too high. Try them.
Connect one bridge rectifier's AC terminals to one piezo disc then connect the DC outputs of all the rectifiers to the capacitor.

People use a piezo disc as a microphone on a drum. When they hit the drum HARD then the piezo disc is violently flexed and produces a voltage and current spike.
It is completely different when compared to a foot moving in a shoe.
 
thats why I sugested he look at linear techs, energy harvesting chips, also there is a kit with a flexible strip, it might be alot better in a shoe. Also look on the weurth site, type in energy harvesting, there are 2 video's one is long. somewhere around the 30 min mark is a fair bit of good information on harvesting energy like this.
I cant tell you how or why I know this, but I have seen some amazing stuff done with tiny amounts of harvested power .
 
BTW where is the original thread? I have no idea what your doing
 
He has many threads here and on other website forums.
He is trying to charge his phone from the piezo discs in his shoe. It is a school project and he must show that the phone is charging.
Maybe he uses the phone until its battery shuts off then charges it with his piezos then uses his phone to make a call for a few seconds.

Maybe he can cheat a little. When a battery goes dead then rests, some of its power comes back.
The battery in my car ran down when I left the lights turned on and it would not start. After resting for half an hour with the lights turned off it started fine.
My electric RC airplane battery ran down and the motor turned off. After resting for half an hour it flew for a few minutes again.
After his phone shuts off then he can pretend to charge its battery but actually the battery is simply resting. Then after resting for half an hour it might work again for a few seconds.
 
what about the harvesting chips? they are designed to help charge a battery? now I am totally confused .
So question
1) are you trying to power the phone this way? or trying to charge the battery this way?

2) When is this for? is it after the 24th feb?
 
I didn't read about Energy Harvesting chips but I think they were designed to power an extremely low power LCD watch, unless you have thousands of piezo wafers on a sidewalk with hundreds of people (or cattle) trampling on them.

Lets wait to see what he gets from the circuit in his shoe after he walks in it for 1 hour. Maybe 5V into a huge 10F capacitor then he discharges it with a 100k ohm load. The voltage does not stay at 5V, it drops quickly to 1.85V so the average voltage of the capacitor is 3.4V.
3.4V into a 100k load is a power of only 0.1mW. His phone charges with 500mA at 5V which is 2500mW.

Then he will be walking for 25,000 hours which is 2.85 years without stopping.
 
Dad is involved in something with silicon labs and linear technology and weurth, he and a university have put alot of money into a project, in part it will use energy harvesting, Dads main part in it all is from the biology side, they are looking for developers at the moment. But anyway, I have seen some of the Dev boards for energy harvesting working, Honestly Mr AG they are mind blowing! Personally I have only seen stuff using upto 50mA being powered, but I was told 200mA was possible.
I have read alot on Linear tech site, because of dads project I am doing an assembly at school, mine isnt exactly energy harvesting tho. But kind of similar.
Anyway I promise you that from what I have read and seen, it is more than possible to get useful power from piezo, enough to run a phone?? I dont know. Enough to be worth while in assisting the charging of a phone battery?? I would say yes, with the right Piezo transducer, then useful power available, the one I have seen in action is a kind of plastic strip, looks alot like a strain gauge type thing. I have piezo disc's like used in drums, and I totally agree , having played a little with the Kit, those disc's are a non starter for a shoe type set up, but I can make a Led light if I place the disc on dad's phone and make it vibrate .
As a School project I like it alot, but even with the flexi strips, I cant see them taking the strain day in and day out, inside a shoe. Also I dont know what kind of power you need to make a call, but I doubt you could power it solely from a piezo, but help charge the battery, I would say yes.
One of the energy micro boards we have, has been running for two weeks non stop, doing all sorts. And its powered by TEG and charges a cap bank up, but the whole setup dosnt use much current. It reads some sensors and sends data six times a day by wireless, then sleeps, but the LCD is on all the time.
 
On the subject of phone charging shoes, have a look at this link from 14 years ago:
**broken link removed**
The link mentions a phone call to Tony Blair, the UK prime minister of the day.

Now look at this link:
https://everything2.com/title/The+Electric+Shoe+Company
Which relates to the same pair of shoes, but the phone call was to Richard Branson.
Why the switch from Blair to Branson you may ask?
Because Teflon Tony did not want to be associated with the project.

A more up to date link:
https://techcrunch.com/2011/08/25/nanopower-shoes-could-generate-20w-of-electricity-during-walking/
which shows a different technology for your shoes, dismissing piezo power as being a bit lacking.

JimB
 
The articles showed high tech devices designed by a team of experts over many years.
They did not use some cheap Chinese piezo discs from beepers and assembled (not designed) by a student in India.
 
Interesting stuff Jim. The Nature Article was really interesting!
 
I have had a chance to play with some of this. The best stuff for this project is this
**broken link removed**
Dad has the evaluation kit for this, I have had a play with it! From what I have seen on the scope and from using it on the harvesting boards from linear Tech, I think two small patches of this stuck to a fairly rigid base will do it!
Also on Linear tech download LT spice, on there harvesting page they have a piezo sim heres the link
change the .txt to .asc then run it in lt spice, from what I have seen the patches I linked too will out perform that sim by a long way. So i have gone from being unsure to being pretty convinced if you use the right parts, then its more than do able, in fact depending on how much power you need for the phone, I dont think it thats hard! Those patches will bend upto 20mm radius, but I found a 2-3mm deflection was plenty!! it gave 36V taped to a ruler and bent 2mm then let go.
good luck
 

Attachments

You must log in or register to reply here.

Similar threads

Output transformer of homebrew inverter.
Replies
6
Views
2K
shokjok
S
Will this work for building a bench supply ?
Replies
6
Views
264
schmitt trigger
S
Y
  • Question Question
analog connection for converting single ended to differential
Replies
5
Views
2K
danadak
  • Question Question
Find output of optocoupler for variable input
Replies
6
Views
3K
crutschow
  • Question Question
Looking for a part which works like
Replies
11
Views
3K
Electroenthusiast
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…