I love this kind of stuff. The thermoelectric heatsink for a computer was the first I've ever heard of generate electricity from heat alone. That is based on what travelin said, Peltier.
But also.. I started thinking about Oxygen sensors on automobiles and how they generate their own voltage.
I started diggin in a little more on the oxygen sensors and I came up with this:
"When hot (at least 250 °C), the zirconium dioxide element in the sensor’s tip produces a voltage that varies according to the amount of oxygen in the exhaust compared to the ambient oxygen level in the outside air. The greater the difference, the higher the sensor’s output voltage."
I can't break that down enough to understand what would happen if you put an oxygen sensor in a fire and were able to test its output with a multimeter. But I may have my old O2 sensor to test it.
For if you do not know, an oxygen sensor measures your cars exhaust to check if its rich or lean and will adjust the fuel to air ratio accordingly. The adjustment is made via a voltage signal. Which the oxygen sensor generates on its own.. not by the alternator or battery.
These O2 sensors can generate up to 1 volt. If I can figure how one works exactly, I could hook 6 in series and charge a phone or run my tape player, or charge a few batteries.
But I'm thinking that even at worst but in a perfect world if I have to replicate the exhaust system, I should be able to screw 6 of these into a pipe and run smoke from a fire all day.. they would read that there's no oxygen.. send a 1volt signal each.. x 6 for my 6volts.
I'm sure I'm missing an important element in there.. I'll have to test hands on to understand.
Sweet stuff. These can be had at junk yards for free too. They're a common wear part, cost $20 for my truck. People don't buy O2 sensors at the junkyard. It would be like buying used guitar strings. Great project and cool product these guys got. I don't ever buy stuff like that, but appreciate the tech.
