Thermoelectric Lamp

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I got the idea here:

It's very attractive and well made. However I went to look to buy one; and the source that I found is selling them for over $240.

I'm not paying that! I've decided to design my own. I found a good price on a Peltier module, TEC1-12706 for about 2 bucks apiece with shipping. I bought 10 of them to experiment with. I might buy more; as I'm already dreaming up other possibilities. About 10 minutes after I ordered them I found some going for about a buck and a half apiece with shipping.

I;ll need some LEDs. I'm thinking about buying a Harbor Freight 50 lumen headlamp for about 2 and a half bucks each. They run on 3VDC. All that is left is doing some calculations and adding a voltage regulator.

Since I can grow sunflowers, and press my own sunflower seed oil; I think that I will experiment with that renewable resource. I'm also thinking about building one on an old fashioned kerosene lantern.

I'm in the middle of a huge project right now; so I probably wont get to the build until this spring.

However, when I have some working models; I'll post pictures, dimensions, and a list of materials.

 

[Mark Quayle]

Do some looking elsewhere for the LED's. My guess is that a headlamp will not be as efficient (lumens per watt), as, for example the light on the back of a phone. And I'd start with very low wattage. On the other hand, using a higher wattage LED may itself hold your source voltage limited without regulation. Regulation necessarily will consume some of the energy. But if the source is stronger than I suppose it to be, you still may want to limit it.

I haven't bought much in over 20 years, but there were several good places to buy small quantities back then. Lately I've bought from Mouser and Digi-key.

Have fun!

 

[HARK!]

Do some looking elsewhere for the LED's. My guess is that a headlamp will not be as efficient (lumens per watt), as, for example the light on the back of a phone. And I'd start with very low wattage. On the other hand, using a higher wattage LED may itself hold your source voltage limited without regulation. Regulation necessarily will consume some of the energy. But if the source is stronger than I suppose it to be, you still may want to limit it.

My thoughts were with a variable flame, that I would need to protect the circuit from overvoltage, at max flame, but keep the module close enough to the heat source, that I will still get good light at low flame. Another consideration is that I will have to be sure not to overheat the module. I bought extra modules to give me versatility in how many I might use in the design, and also to allow for damage caused by mistakes, and losses through trial and error.

I haven't bought much in over 20 years, but there were several good places to buy small quantities back then. Lately I've bought from Mouser and Digi-key.

Have fun!

I looked at Mouser and Digi-key; but their modules were kind of pricey; but then again I was looking at different part numbers. There are also shipping charges. I used to be a buyer for an electronics company. I would buy hundreds of thousands of dollars of components per year. Mouser and Digi-key were some of my vendors; but my favorite vendor was Future/Active out of Canada. They would give me excellent pricing for the volume that I was doing; and they trade on the world market so they could track down difficult to find parts. I was looking for a rare, unique, component for the repair of a piece of medical equipment, to find that there were only 7 left of them in the world. They were in Israel. I managed to buy them and have them delivered the next morning; so that I could repair the like saving equipment that day, on the East coast, and ship it to the West coast to save the patient the following day. Future came through! The parts were something like a buck a piece; but the shipping for these small pats, overnight, from Israel, was at least $100. The shipping often would exceed the cost of the parts, on small orders, no matter which of the big vendors I would buy from. I would do my best to consolidate orders, to offset the shipping costs.

All that has changed with Ebay. I got these parts coming on the slow boat from China, on the cheap, with free shipping.

When I have a working model; I'll also list my sources for the materials. Thanks for calling that detail to me attention.

 

[Mark Quayle]

My thoughts were with a variable flame, that I would need to protect the circuit from overvoltage, at max flame, but keep the module close enough to the heat source, that I will still get good light at low flame. Another consideration is that I will have to be sure not to overheat the module. I bought extra modules to give me versatility in how many I might use in the design, and also to allow for damage caused by mistakes, and losses through trial and error.

I looked at Mouser and Digi-key; but their modules were kind of pricey; but then again I was looking at different part numbers. There are also shipping charges. I used to be a buyer for an electronics company. I would buy hundreds of thousands of dollars of components per year. Mouser and Digi-key were some of my vendors; but my favorite vendor was Future/Active out of Canada. They would give me excellent pricing for the volume that I was doing; and they trade on the world market so they could track down difficult to find parts. I was looking for a rare, unique, component for the repair of a piece of medical equipment, to find that there were only 7 left of them in the world. They were in Israel. I managed to buy them and have them delivered the next morning; so that I could repair the like saving equipment that day, on the East coast, and ship it to the West coast to save the patient the following day. Future came through! The parts were something like a buck a piece; but the shipping for these small pats, overnight, from Israel, was at least $100. The shipping often would exceed the cost of the parts, on small orders, no matter which of the big vendors I would buy from. I would do my best to consolidate orders, to offset the shipping costs.

All that has changed with Ebay. I got these parts coming on the slow boat from China, on the cheap, with free shipping.

When I have a working model; I'll also list my sources for the materials. Thanks for calling that detail to me attention.

Ha! I bet you are familiar with the name, (rats—old person moment), —ah yes! Murata-Erie, from State College, PA. They made high quality (as in NASA duty) ceramic chips and boards. I've done some electrical work there. I have an AA in EET (1977), so I understand something that the circuit board assemblers there didn't, who asked why, if the only difference they could find in two different boards was the size, that the smaller one had a higher operating frequency! I felt so smart, because I knew why! Me—a lowly electrician!

 

[Mark Quayle]

My thoughts were with a variable flame, that I would need to protect the circuit from overvoltage, at max flame, but keep the module close enough to the heat source, that I will still get good light at low flame. Another consideration is that I will have to be sure not to overheat the module. I bought extra modules to give me versatility in how many I might use in the design, and also to allow for damage caused by mistakes, and losses through trial and error.

I looked at Mouser and Digi-key; but their modules were kind of pricey; but then again I was looking at different part numbers. There are also shipping charges. I used to be a buyer for an electronics company. I would buy hundreds of thousands of dollars of components per year. Mouser and Digi-key were some of my vendors; but my favorite vendor was Future/Active out of Canada. They would give me excellent pricing for the volume that I was doing; and they trade on the world market so they could track down difficult to find parts. I was looking for a rare, unique, component for the repair of a piece of medical equipment, to find that there were only 7 left of them in the world. They were in Israel. I managed to buy them and have them delivered the next morning; so that I could repair the like saving equipment that day, on the East coast, and ship it to the West coast to save the patient the following day. Future came through! The parts were something like a buck a piece; but the shipping for these small pats, overnight, from Israel, was at least $100. The shipping often would exceed the cost of the parts, on small orders, no matter which of the big vendors I would buy from. I would do my best to consolidate orders, to offset the shipping costs.

All that has changed with Ebay. I got these parts coming on the slow boat from China, on the cheap, with free shipping.

When I have a working model; I'll also list my sources for the materials. Thanks for calling that detail to me attention.

I'm guessing you'll have to have several of those things 'in the chimney' to get much light from LED's. I would think the no-load voltage rating is pretty much meaningless.

 

[HARK!]

I bet you are familiar with the name, (rats—old person moment)

No.

Murata-Erie, from State College, PA. They made high quality (as in NASA duty) ceramic chips and boards. I've done some electrical work there. I have an AA in EET (1977), so I understand something that the circuit board assemblers there didn't, who asked why, if the only difference they could find in two different boards was the size, that the smaller one had a higher operating frequency! I felt so smart, because I knew why! Me—a lowly electrician!

Shorter traces have a shorter wavelength, therefore a higher resonant frequency?

I don't know why; but off of the top of my head, that is my best guess.

Years ago I had the opportunity to visit the Wells Gardner factory in Chicago. I was escorted to a room where the top techs were trying to figure out why there was noise in the picture on a monitor. They had spent significant time studying this problem. They said that they had already replaced the board with a known good board. There were two curved, parallel, vertical, rails that connected to the CRT. The board rested between these rails on the bottom; and a metal plate was screwed. between these rails. on the back, to help protect the neck of the CRT.

I told them to take off that plate. To everyone's surprise the noise on the screen disappeared. There is a 90 degree phase shift through a resistor. Different metals have different resistances; so where they meet, in effect, one becomes a resistor. There was a phase shift in the ground plane which was causing the noise.

I had run into the same problem with my own company, when we ordered to have some metal enclosures fabricated for an audio device that we had designed. Some of them were fine; but some were not. Some of them would give us 60 cycle hums on the output but only when we screwed the covers on. Upon close inspection we saw the difference in the covers for some of the enclosures. The factory who made them for us must have run out of one type of metal stock and switched to another. We sent all of the enclosures with unlike metals back; for them to make it right.

When I saw the unlike metals at Wells-Gardner; I instantly knew just what to do. They looked at me like I was a genius; but I had already gone thought the headaches of gaining the experience of understanding why such problems can exist.

 

[HARK!]

I'm guessing you'll have to have several of those things 'in the chimney' to get much light from LED's.

I'm not sure. I'm considering attaching one to a heat sink, and applying flame directly to the heat sink. it will take some experimentation. I'm also considering water cooling the cold side of the module for greater efficiency.

I would think the no-load voltage rating is pretty much meaningless.

I would tend to agree. I don't have much experience with these components. I used to see them in lab grade centrifuges; but I never had to replace one.

 

[Mark Quayle]

Shorter traces have a shorter wavelength, therefore a higher resonant frequency?

Yes, basically, though it's almost like saying the opposite of resonance. It's antenna theory. Long story short (no pun intended), a long antenna radiates EMF at a certain long frequency (and nearby frequencies, also, but less efficiently), and a shorter antenna at higher frequencies, because of those shorter frequency wavelengths.

The length of co-ax feed to an antenna is pretty much irrelevant, as long as the grounded conductor is the same length as the core conductor. But the antenna length has everything to do with the frequency. The longer the antenna, the longer the radiated wavelength.

The 'lead length' of the conductors of the printed circuit board also, if signal frequencies on them are high enough, begin to radiate EMF. Longer wavelengths won't radiate off them. So the shorter the conductor length (smaller the circuit board), the higher the frequency at which it can operate without losing efficiency and causing cross-talk etc.

This is also, BTW, the reason tiny chips can do higher frequency nowadays.

Let's say you choose a certain alternative voltage frequency (visualize a sine wave) to put onto a wire (antenna) of just the right length to resonate. You will get a 'standing wave', that is measurable at its peaks and troughs (one quarter and three quarters down the length of the antenna, but zero at where the waveform crosses from positive to negative and back, thus, no reading at the beginning, middle (1/2 wave) and end of the antenna. And no current is being drawn and no radiation is occurring. But if you shorten that antenna to 3/4 wave, or even lengthen it to 1-1/4 wave, it will draw current and radiate EMF off the end of it. (Too high a voltage waveform will draw so much current that a less robust system will burn at its weakest link.)

 

[Mark Quayle]

I'm not sure. I'm considering attaching one to a heat sink, and applying flame directly to the heat sink. it will take some experimentation. I'm also considering water cooling the cold side of the module for greater efficiency.

I would tend to agree. I don't have much experience with these components. I used to see them in lab grade centrifuges; but I never had to replace one.

I've never used one, though I've seen heat-operated fireplace/wood stove fans, but they aren't very strong.