So what is a Peltier device? Well its a thermoelectric device, or a heat pump. When you apply electricity to it, it pumps heat from one side of the device to the other, creating a very cold side and a very hot side.
Well what is it used for? Most people use it to cool computer processors, or make small mini fridges and coolers. Since it doesn’t require moving parts its very quiet. Plus it can reach freezing temperatures very quickly.
However, there is a catch, remember how I said one side gets hot? Well you need to cool that side somehow otherwise it will overheat. Normally a good way to do that is to use a large piece of metal called a heat sink, some thermal grease wouldn’t hurt either.
Here is one in action via “laszlofabian,” you can see it go from room temperature to frozen 50 seconds into the video.
Another really cool thermoelectric property of this device is the ‘seebeck effect.’ If you apply a very large heat to one side and a cool source to the other you can generate electricity. Sweet!
Now of course there is a catch. Most of these devices have a low efficiency (4% or so) and in order to generate more power you need it to be very hot on one side and very cold on the other. The bigger the difference in temperature the more power, and that is hard to accomplish. Plus the devices aren’t what you would call super cheap (approx $15 for a 350W device).
Now if you had a wasted heat source and a cooling source you could turn that wasted heat into free energy. Awesome!
Green technologies are eco-friendly by reducing/collecting wasted energies or creating more energy efficient methods to perform common tasks. There are a lot of people posting amazing “perpetual motion machines” that skew the public to be skeptical of what a real break through looks like. I think that its great that a lot of DIYers are trying to create new breakthroughs that save energy, but a lot of times these projects aren’t realistic and many creaters rarely point out their design flaws. Sometimes you have to realize why the big corporations aren’t doing it and there are no miracles that the government squashed. Trust your common sense and the publications from reliable sources like engineers and scientists, they studied this much longer than that infomercial guy.
Now I just want to rant about two items, one from the infomercial world and one from the DIY community. The shaky flashlight and the awesomely cool spinning Tesla Turbine.
1. Shaky charge flashlights are not a breakthrough, they are at best semi efficient, a hand crank one would be able to generate more power for the effort you put in. The shaky flashlights push a magnet through a copper coil to create a current. Here is the flaw, the current created in relative to the speed in which you shake. Plus the magnets stop moving after each shake because its hits a side, wasting effort. Hand crank machines rotate a magnet to induce current into a coil at a constant speed. Plus with gearing it can be done with fewer coils and the user could spin at a lower speed. If you consider the shaky flashlight a breakthrough you may as well buy a snuggy
Tesla turbines, are really cool, I personally love to watch them, but essentially they are still just a turbine. Why are they important? They are more efficient at high rpm and easier to produce designs. Fans that are spinning at a high a speed are harder to design and are more suceptible to mechanical stresses. A lot of people design these without any mention of where they plan to harness their energy from or how they are going to translate the high rpm to electrical power. Now just because you designed one you can power from your air compressor doesn’t mean you saved the world. Unless you find or channel a high enough wind source into your turbine and integrate it into a real system with a charging bay its not green. If you want to learn more about tesla turbines see this link.
Now if you want to save the world but you don’t have any ideas there are some much easier ways than creating turbines and mythical machines.
1. Buy energy saving devices, they use less electricity and though the initial cost is higher they save more over the years you need to operate it. Energy efficient bulbs, refrigerators, washers and driers.
2. Don’t turn your heat so high in the winter and don’t turn your air conditioner on to an icebox. You will save in your bills and you will stop causing those brown outs in the summer.
3. Live closer to where you work or use public transportation. This way you don’t need to drive so much and use a non renewable energy source.
4. Don’t spend as much on tools and miracle items that you won’t use or do not have a dual purpose. Otherwise you produce trash when you finally give up and throw it out.
5. Don’t be lazy, pick up your trash and sort it. Many states fine when you don’t and relying on the public services to clean it up costs tax payers money that could have been invested elsewhere.
6. Reuse what you can rather than buying a new one all the time. Use Craigslist or give away items that you just upgraded from. A lot of people will still need them.
Anyhow its kind of crazy how old that list sound, but its the easiest thing to cut.
So its finally suppose to be a warm weekend here in NY. If I’m lucky I’ll get the chance to test out my new Arc Welder. Someone donated it a couple months ago, but its been too cold to start testing it. If you don’t know what welding involves check out the video below. Its definitely a skill that requires practice. I’m not any good but I hope to get there. This video gets me drooling.
The donated welder came with some welding sticks and a disappointing hand held mask. It was flimsy and the lens didn’t fit well. I finally dug into my wallet and bought a mask from harbor freight that could auto darken. I chose the blue flame design because as we all know flame decals make things go faster.
The auto darken feature was pretty handy. Normal welding masks have a very dark tint, you are pretty much blind until the electrical welding arc starts to form. In arc welding you have to have good coordination, feeding the weld rods into the joint while maintaining a very slim distance. If you feed too slowly the arc gap becomes too wide and it stops welding. If you feed too fast you get the rod stuck to the metal and it starts shorting. With an auto darken mask there is a sensor which detects the presence of the arc and darkens only when you are welding.
The mask I bought was solar powered (had a battery too) and it could also adjust darkness levels. It was a bit expensive ($59) but safety wise it sure beats these guys.
Expert Village has some really good video tutorials to start with.
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I was thinking of little innovations to make in my usual thinking spot. Then it hit me, I should building an automatic toilet flusher. I needed a little intro to what all the little moving parts in a toilet were called and I decided to take Toiletology 101. Its kind of amazing how we take bathrooms for granted.
I thought this video was a bit impressive. I’m glad all that junk mail I recycle is going in its proper place.
So I’ve been thinking about making a 3D prototyping machine for a while now. I’m lazy and making the parts by hand is a chore. 3D printers and cutters open the ability to draw a model on my PC and create it without actually measuring and cutting all the parts.
So far I’ve seen a couple types
CNC Mills/Lathes (computer numeric comtrol)
Deposition 3D Printers (Melted Wax or Plastic)
SLA (Stereo Lithography Apparatus)
Liquid Powder Printers (liquid hardener added to a powder bed)
Paper 3D Printer(sheets of cut A4 paper with glue)
http://www.mcortechnologies.com/
1. CNC routers are great tools, they are subtractive and are used to manufacture parts out of wood, plastics, and even metals by cutting chunks from a solid block of material. Most CNCs have a cutting tool mounting on a XY linear slide which allows a cutting tool head to travel across the entire region. The tool head is mounted on a Z axis which lowers the head to cut or lifts it up to jog to the next area.
One of the big drawbacks of a typical CNC is the inability to cut underneath the material. Since the tool only cuts from the top you would not be able to do things like cutting the bottom of an arch without flipping the material over.
CNCs can produce very strong models. The result will have the strength of whatever material you cut, so long as your tool head is powerful enough to cut through.
Some great CNC links include
www.cnczone.com
2. Deposition/3D Printers are additive. Instead of cutting away material they have a tool that deposits little droplets of wax or plastic. The plastic or wax is melted in the tool head and ejected out of a nozzle.
Most of the wax/plastic units I have seen offer no choice in colors. Wax tends to be weak and will break if dropped. The abs plastic depositing machines are usually strong. Comparable to Lego bricks. These typically can’t print archs either since the print head needs some support underneath in order to print successfully. Some printers offer two heads, one that ejects the material and one that creates supports that are removed after the model is finished.
RepRap is an interesting deposition type printer that uses a thermoplastics to create models too. Its more of a hobbyist machine that has the ability to machine it’s own parts. Replication! Well at least the non metal parts, circuits and others are still bought.
Another open source machine that has achieved some popularity is Fab@Home
Most of these machines though only print in a few colors, pretty much the color of the material being feed through the thermal extruder.
There are also some versions of these machines that use chocolates, sugar glue and other fun materials but the general rule is they liquidfy and deposit it in layers which eventually harden
3. Now SLAs are the definitions of awesome. They work with a bath of a UV sensitive resin. There is a platform that first sits near the surface of the bath exposing only a hairline fraction of the entire UV resin tank. A fancy 100mW or more UV laser turns on and cures the resin that it hits. The SLA machine does this layer by layer and since the laser is such a fine tool and more controllable than a extuder head it can achieve higher resolutions than deposition printers can.
These models have great accuracy but their models also only come in one color. The models are fairly strong, stronger than wax but most plastic printers can printer stronger models.
To my knowledge no one has made a homemade SLA.
4. Now I added the powder type 3D Printers into their own category because even though they deposit materials they act similar to SLA. In a powder type 3D printer there are two trays. One for powder to be used and one for the model. The model tray is initially empty. It then gets filled with a layer of powder and a print head moves over the powder depositing a liquid hardener that reacts and hardens the powder at select locations. Another layer of powder is then added and the process repeats until the model is done. Then the model is separated from the unhardened powder and is dusted off and sealed. Because the powder acts as a support complex shapes can be made. If the model was a hollow ball the powder material would support the shape while its being printed but it would come out as unhardened powder.
Since these liquid deposition tools don’t need to be heated they usually rely on a inkjet like tool head which allows it to easily achieve higher resolution since the tool head is created by a stereolithograpy method and it is typically faster since the print heads have a matrix of nozzles.
Also a lot of these models use actual inkjet print catridges so a wide variety of colors can be printed on the model. Something the other machines did not offer.
There have been some successful replications of these machines but none that also produce color on the DIY side of the world. Let me know if you find one and I will post it.
5. Paper 3D Printer? Now this one is a completely new concept. MCOR had the bright idea to glue layers and layers of paper while cutting the paper to make a 3D model. I have to say this was pretty smart. The models come down drastically in cost since glue and paper are commonly avaliable and cheaper than thermoplastics. (I don’t even want to think about how expensive the SLA resin is ) Now this company hasn’t actually sold their printer but its pretty interesting. It seems like it would be a lot greener than the other methods. CNCs produce waste, thermoextruders produce heat and their models are not always recyclable and SLAs are extremely expensive.
