I got some cheap solder with my solder station and it was the bane of my existence. Found some leaded solder I think I got from radio shack years ago and it works so well. I hate to say it but I haven’t yet had good success with unleaded solder. Someone please save me from the brain damage.
MELF stands for Metal Electrode Leadless Face although anyone who has had the pleasure of working with them will tell you it stands for Most End up Lying on the Floor.
Sam Zeloof (sam.zeloof.xyz) has been working in the area of DIY semiconductor fabrication, and has successfully fabricated working ICs (from 6 - 100 transistors). He’s done an incredible job at reaching ~1970’s technology levels in a home lab.
These examples are still very small-scale compared to even simple microprocessors, etc - but it’s fascinating to see this level of technology becoming more accessible.
That does actually exist, it’s called a toroidal transformer. Instead of a tube shape though it’s a donut shaped piece of ferrite with the primary and secondary wound one on top of the other. The different types have different use cases though, as far as I remember the toroidal ones have higher leakage current. Marco Reps has a good video on his YouTube channel where he explains some of the differences if you’re interested, although he mainly focuses on what’s important for precision electronics.
Depends on the use case. It is a very good idea to harvest small amounts of energy for example to use it in a calculator or a clock or a remote control or button or light switch. This way you never need to replace batteries or have them leak and destroy the thing.
Apart from that. There aren’t many use cases for those very small amounts of energy. You have to ask yourself what you’re going to use that small amount of energy for. Because batteries and wires are way cheaper. And they store amounts of energy you’d need 20 years of harvesting with equipment that costs a lot more. It just depends on the use case. And for little amounts of energy, the use-cases are severely limited.
Inspiration for building something hit me when the following things happened:
I learned that small amounts of electricity can be harvested from a single drop of rainwater, both from the kinetic energy and shorting two electrodes. I don’t know the how, but I’ve seen something like 200mV from a small trickle of water from a faucet.
I moved to a place that where it rains a lot and bought a house with which I could do some experiments. This house is also on a slope.
I got a 3d printer.
I figured that I could create a small, maybe 1cm x 1cm device that could harvest 200mV when a drop of water hits it. 200mV isn’t much, but if I had 100 of them hooked together in a 10cm x 10cm square, that could be somewhere between 1-100x that voltage (though, more likely lower than that unless it’s a downpour).
Then I got thinking, well it’s water, so after the kinetic energy and whatnot has been harvested it could go into a large bucket at the top of the slope. That large bucket could then be connected to a tube that’s connected to this mini 12v dc hydro generator I bought off amazon. Of course then I could use the energy generated/harvested during the day to pump water back up to the bucket at night… (ok, would have to be a large bucket and I realize this is still small amounts of electricity)…
I guess the reason we don’t see commercial systems like this has to do with energy density. After printing and prototyping and hours of trial and error, I may arrive at a device that can harvest/generate 0-15v depending on the weather. I imagine if I were to buy some TI energy harvesting devices and put them all together, I would be able to get enough energy to charge my phone in a day, but it may set me back the price of a house and may take up the size of a room to do so.
I guess my realisitic-use case would be to take something like what I just described and use it to power some outside LEDs. Then, everytime it rains, the LEDs would twinkle, and that would kind of be neat to see. Especially if these devices were installed in something like a raingutter system with individual LEDs, sort of lighting up roughly wherever rain drops were hit. No energy stored, just used as it’s harvested. It sounds like if it did work, it would be a big undertaking and would require quite a lot of time and money to build.
Wow. Thanks for the link. Unfortunately this video isn’t very scientific. You don’t measure electrical energy in millivolts but in Jules (or watt-hours). Or in an experiment like this you would measure electrical charge (Coulomb) generated by a certain amount of water.
And I would expect the charge to come from the clouds or air or something. That would mean the water wheel shouldn’t generate any electricity in his experiment.
Measuring Voltage is kind of wrong. You also get a reading of a few hundred millivolts if you randomly stick your multimeter somewhere. Or take the probes in your hands and squeeze them. That also generates a few hundred millivolts. But it isn’t energy.
I’d love to see his experiments repeated in a bit more scientific way. And someone to figure out how to do that at scale. How to connect a square meter of those electrodes. And how to arrange them.
If you actually build something, make sure to document that in a blog with pictures or video for us. I kind of want to know if it’s really 50W per square meter of free energy in the rain drops.
Hopefully I picked the right video here, he has hundreds. In one of the videos robert measures mA with some of these in series and powering some LEDs, I believe, or I’ve confused that with another video.
From the paper, I just skimmed but it seems that most of the energy is kinetic, then possibly converted into static? I’ll obviously need to do some actual reading.
They are 22ohm resistors. You can see they are resistor by the marking R on the pcb. The first two digit is the value (22), the last is the multiplier (0), so it would be 22*10^0 =22 ohm
I am pretty busy this week, I am posting when I have breaks and I don't have it with me. When I'll have the time I will make a post with photos and measurements and I will probably also open it up.
Quartz heating elements are also resistors that emit light, but i’ve never seen anyone complain about them, people tend complain when they dont actually
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