Official circuit design help post :/

[flare09]

Hey everyone. It's been a while since I have posted here, I have had some family issues and random stuff pop up and take me away from my rgb build. It's sitting in a box under my bed :/vim still trying to figure out the pcb there since I was scammed, and can't really put more money into it.

Where I'm looking for help is with a project that I have diverted most of my time to now. It is a ring I'm hoping to build for my gf before she comes home. I can't really talk about where she has been but I have a bit more time to try to finish this project.

I'm hoping to use the ltc3105 chip to convert thermal energy into just enough voltage to lite a few LEDs. Does anyone have experience with this chip? Or would anyone like to help design the circuit? As a side project with reimbursement...

And I was wondering why somewhere doesn't have a place that can produce customizable partner chips for microchips. Think, resistor array, except with different values, capacitors, inductors and other passive components all in a single chip.

 

[pschlosser]

monster.com

Something this special, for a fiance's ring, warrants proper funding. Not low-balling hobbyists.

Get the right help and get it done.

 

[Bionic-Badger]

Have you even done any research on that specifically named chip? Looking at the specs on the website it looks like a typical step-up regulator, not something that could harvest thermal energy. Anyway, that thermal energy harvesting idea is a crapshoot for those low temperatures: you need large temperature differentials for usable power. You'll never get that in a ring unless you attach it to a radiator or something. Why don't you just use a battery?

Hell, if you want the ring to light up, go fix a tritium vial in it. It'll last for 30 years and requires no electronics... if that costs too much you need to GET A (better paying) JOB like Pschlosser is implying. Your GF will be more happy with that than some ring.

As for your last pondering: because manufacturing custom components is expensive, and reconfigurable components are expensive too. Think of the orders of magnitude price difference between even a potentiometer and a resistor. Whereas a cheap pot may go for $1 in bulk, resistors cost $0.01-0.05 a piece. Same thing for making computer chips (I got to make an integrated circuit for a mere $1000, and all it does is ADD TWO BITS!), vehicles, artwork, or basically anything in the world.

 

[Things]

Just as a reference, it costs about $10,000 to make a custom design 1x1cm chip on silicon. That'd be why

 

[Bionic-Badger]

The $1000 figure I quoted above was for 1x1mm^2 so 1/100th the size -- and that was still a good deal for that process (normally it's $1200/mm^2 if you buy a bunch at a time), and included the workshop too.

 

[flare09]

pschlosser: this is a special project, but not that special...

im sorry to have misled you guys, im not proposing yet..haha but it is for a special occasion. at which i am not at liberty to discuss publicly.

i feel like the hobbiest community contains professionals well suited for the needs of this project. as i am not an EE, i have trouble understanding most of it, but i know there are plenty of people out there that can throw this (design the board) together in an hour.

bionicbadger: this dc/dc converter will be used in conjunction with two HV56 eTEG modules by micropelt, they will be putting out .6V at 60mA each at 50K delta. the average i am predicting is 30K which is about 25mW total. all insidde a 3mmx3mm package. im using ultra low power leds, i will test a few different ones, the 1mA 1.9V up to the 5mA 2.9V to see which work best for diffused lighting. i know its not going to be that bright.

the body of the ring i will be using is not cheap. i have two ceramics, the first, which i may use is zirconia stabilized alumina. the other is a yittria toughened zirconia alumina.
if these end up too brittle i will fall back to a nice titanium. i have a machine shop that can work the tolerances. i just need the circuit to put in it.

i came across moses, they do custom dies apparently? but i just think it would be a decent investment, if TI came out with a chip, that was going to sell in the millions, and made a companion chip that contained all the resistors and capacitors the chip needed externally. saving on size and complexity of the final product