Wednesday, April 26, 2006

Launching your own satellite

OK, I have to admit, this is probably out of most peoples reach but it isn't as far fetched as it can sound. To build a satellite doesn't take the wealth of a small country anymore. With the CubeSat program started by California Polytechnic State University it mustn't cost more than US $40,000 to launch your own hamster space station. For this sum, they will take care of everything pertaining to the launch. You just have to supply them with your satellite to be, conforming to their CubeSat standard. The CubeSat is standardized to a cube (hello!) with the size of about 10 cm so leave the next Hubble to the big guys.

The CubeSat program is really aimed at universities and high schools (over 60 world wide so far) but private companies have also joined so if you can fork up the dough, I'm sure they will launch your creation.

Tags: , , ,

Tuesday, April 25, 2006

Choosing an actuator

When building an electronic project you often want something to move. If you were building a robotic arm, that sure as hell would be boring if it couldn't move, now wouldn't it. You want it to bend like a regular arm and you might even want it to be able to grip things. And then of course you want to put the arm on a moving platform so it can go pinch your collegue's buttocks. So you want the platform to move somehow. All these types of motions require actuators and it is crucial that the right type of actuator is chosen for every job.

First of all we can divide the different types of actuators into electric, gas and fluidic (the rubber band is not to be despised but I won't cover that here anyway). By electric, I mean powered directly by electricity, not controlled by electricity. Controlling an actuator by electricity is something you can do with almost all actuators.

Let us start with the fluidic ones. In that group we have pneumatic and hydraulic actuators. These are most often linear devices and the most common linear device is the piston. A piston works by letting compressed air (pneumo-) or liquid (hydro-) in through a valve. This pushes the piston forward. To make the piston go back, the pressurized fluid is let in on the other side of the piston, pushing it back. Repeat this fast enough and you have a jackhammer.

Another type of pneumatic actuator is the artificial muscle (you can even build these yourselves). It is build up of a woven tube which, strangely enough, shortens when filled with air. As it shortens it thickens, thus allowing it to contain more air.

They seem very simple operations but to build a system using any type of pneumatic or hydraulic actuator you also need a pumps (this can of course be an electric motor but I count this as indirectly powered by electricity) , filters, valves and pipes. This can be quite cumbersome if you are making a small project. Though, since you can store compressed air, you don't need to have the generator in you machine while it is running (if you are running it for a limited time). This is not true for hydraulic systems since liquids are next to incompressible.

The big advantage with fluid system is that by separating the actuator from the power generator, the actuator can often be quite small even though it is very high powered. So even though the whole system is large, the actuator part of it can be very small compared to the forces generated. Also an advantage, if you have a tank of compressed air, it can be released very quickly generating huge forces. And with a closing of a valve, the pressure can be held up thus exerting a force without loosing energy.

Moving over to electric actuators, the most common is, of course, the motor. Turn on the electricity and it starts spinning. Very simple. Of course, when it comes time to choose a particular motor it gets more complicated (brushless or not, AC or DC, torque, gears, etc.) but I'll leave that for another day.

The one thing a motor lacks is an easy way to control its position. To do that you need some sort of feedback (on the axle for example). If you need to know exactly how fast a motor is turning or what angle the axle is at, the stepper motor is probably the way to go. A stepper motor is a motor with multiple electric coils. By choosing which coils are active at a certain time the motor's position can be controlled very accurately. The downside is that it is not trivial controlling the stepper motor. But it is not that hard either so with a stepper motor controller or some tinkering with a MCU (microprocessor controller unit - basically a processor and memory in one IC-packet) I'm sure you can handle it. If you are on a budget, cheap stepper motors can often be harvested from used disc drives (the 1.44" kind, not any new hard drives since they have abandoned the stepper motor).

If you are not interested in continuous rotation and only want to control the angle of a axle, the servo-motor is very convenient (built into every remote controlled car). It is basically a regular motor with a feedback system built in to it. It is controlled with PWM-signals (pulse with modulation) which are very easy to generate. The only problem is that it is very time consuming to generate so you probably have to dedicate one MCU for controlling servos. There are of course ready made servo-controllers if you need to control multiple servos.

There is one more electric actuator that is quite interesting and that is the muscle wire (also known as flexinol, nitinol and a number of other brand names). It is an titanium alloy that contracts a few percent when heated. So by running current through it (thus heating it) it will contract. Let it cool down and it can be pulled out again. As it won't return automatically, you will need something to pull it back such as another muscle wire or a spring (or maybe gravity is enough, depending on the application). It is hard to build a system more compact than this. It also has advantages such that it is completely quiet.

I've left the gas category and engine to last. If you own a car or if you live in Taiwan, as I do, and have a scooter (13 million scooters on 23 million inhabitants) you should know the basics of the engine; exploding gases, the Carnot cycle and that kind of stuff. Sufficient to say is if you need much power and your project is an outdoor project an engine can be useful. It doesn't have to be too complicated, just look at all the RC-cars and aircraft with engines. There are engines from one horsepower and up so if you are preparing for the next DARPA race (or ELROB 2006 in Germany) you'll probably find something. Your neighbors lawnmower is of course a prime target for a engine on the cheap.

Think I left something out? I know I have; both some more common actuators (steam engine, ultrasonic motor, piezoelectric motor) and some less (tractor beam). Whatever you are building there is something out there for you, but if you didn't find it here, you have to start looking yourself.

Tags: , , , , , , , ,

Monday, April 24, 2006

Pringles antenna

Do you get a bad connection in your WiFi-network? Is is probably because you have a to bad antenna. If you know where your accesspoint is located or if your computer is stationary it is really no point in blasting out those precious radiowaves everywhere. A better solution would certainly be to use a directional antenna. Cell phone operators use them all the time alongside roads and surely you can too.

There are many plans out there for building your own directional antenna. Most famous is absolutely Rob Flickenger's Pringelscan antenna. It is (probably) a Yagi-Uda-antenna much similar to the one you have on your roof receiving TV-signals.

If you don't want any more Pringles after finishing building your extreme macro lens you might want to consider other designs made from tin cans (finally we know what Warhol was doing with those Campell cans). These are waveguide designs and apparently work much better (about 9dB or 8x in signal strength) than a Pringlescan. So if you need some long range WiFi go out and buy yourself some tomato soup and start building!

Tags: , , , , , ,

Sunday, April 23, 2006

News from the Faire

I, like the most of you, couldn't go to the Maker Faire today and therefore had to read about it all over the web. Seems like it was a big hit though. Hack a day mentions that the people from monome were there showing of their cool music control unit monome 40h. Really cool stuff. They got a very cool video over at their website showing it off.

Cnet has posted a long article about the fair too; a very good read. They talk about how they are getting the kids involved in DIY from a very young age. Apperantly the stop motion animation was a big hit for the five-year olds. That's the right way; get them when they are you and impressionable, just like the church!

There should be a faire like this in every bigger city once in a while. I would have loved it had I been five years old. In my mind I am still five years old and I would love it.

Tags: Maker Faire, monome

Boards for electronic projects

There are many electronic circuits out there you can make yourself. And designing your own is not that hard either. But whatever you make you need to put it on something. Here there are multiple alternatives depending on both the complexity of the circuit and how permanent it is. I'll give you an overview:

The first thing is usually to place the components on a breadboard. A breadboard is really only a board with holes and connection in strips between the holes. It is very easy to build on these but circuits can very soon become very complex on hard to look at. It is also very easy to put a component in a wrong hole and get hell trying to find what is wrong with the circuit. A tip for those building on breadboards is to always cut the wires as short as possible and not let them become a big nest above the components. Otherwise it is quite easy to pull one out and not remember where it was supposed to go, or even seeing that it was out. They are great for prototyping but after that you really have to move on to something else.

If you need something a little bit more permanent than a breadboard, a stripboard is the way to go. It is a board with holes just like the breadboard. One of the differences here is that the holes are connected with copper tracks that you can break yourself. By breaking the copper tracks and creating new tracks with wire simple circuits can be made. The other difference is that the components need to be soldered into the holes. Since the tracks are very wide this is very easy. Just be careful so you don't connect two tracks that shouldn't be connected with solder. It can be a bitch removing, even if you have a solder sucker (a vacuum pump) or solder wick. If you have a cut close to where you are desoldering the track can very easily come loose.

The stripboard is the easiest method for building a permanent circuit. But after a while you will want to move on to more complex circuits that don't lend themselves easily to be transferred to a stripboard. Then you really need to move on to a custom made PCB. There are many ways to make these, all depending on how complex circuits you have.

The most common way to create your own PCB is through etching. When you get board made for etching it is made of three layers.
1. Photoresist
2. Copper
3. Glass fiber board

The first thing you have to do is cover the photeresist where you need to have copper tracks. If you have a very simple circuit this can be done with black tape. If it is more complex you can print out your circuit on a OH-transparency or through a laser toner transfer (have not tried this method but it looks promising). Then you subject the photoresist to UV-light. This removes all of the photoresist which wasn't covered and leaves clear copper. This copper can now be etched away with chemicals. You are then left with a glass fiber board with copper tracks just where you wanted them. After drilling holes to attach the components you are done.

There are some limitations here but basically it is a very good process that works with most circuits you are going to make yourself. Some cicuits though are too complex to make in this way. If you need very high accuracy, e.g. for surface mounted components, or if you need more than two layers (front and back) of tracks, you really need to send away for a professional firm to make the board.

This is not hard, there are multiple firms that do this. In the States you have Pad2Pad and ExpressPCB and back in Scandinavia, Elfa can take care of this through Elprint. There are of course many more, wherever you live.

Another way to make board are by milling away the copper. Companies or universities that want high quality PCBs without needing to send it away might have a PCB milling machine but unless you work in such a place you will probably not encounter this method though I can attest to it being very good (no need for drilling the holes yourself).

There you got it! Now you only need a CAD program for circuits too. Easy enough. Can recommend Eagle which have a freeware version of there program (maximum 100x80mm boardarea). Only remember that if you are sending it off, it should be able to handle Gerber-files since this is the standard for printed circuit board.

Tags: , , , , ,

Building your own mp3 player

I have to confess, I am perfectly happy with my tiny iRiver mp3 player. But for those of you that value homemade more than Korean massproduced stuff, you can actually build your own mp3 player. Of course, you could always take that extra computer you have in your closet but that's kinda cheating, isn't it. Wouldn't it be much more rewarding to build it from scratch? Or from as close to scratch as you get with todays IC-cicuits. There are kits on the market that allow you to do just that.

If you are not looking for anything portable, the PJRC MP3 player might be the way to go. It uses a regular hard drive for storage so it can probably handle all the music you have (if you are not iTunes Music Store). You can buy this kit either as fully assembled (only add HD, memory and power source) or, for those of you with a soldering iron and some spare time, in parts (PCB plus components).

Mp3 was really made for carrying along with you and you can of course make a portable one yourself. One way to go is the MintyMp3. It is quite small but you have to have the PCB made for you at a factory since it is a 4-layer board.

A better way to go might be the Avr Butterfly Mp3. It is an open source project aimed at creating a hardware design and software for and easy to make mp3 player. Even though the project looks quite young it could be worth a try. Avr processors are very simple to program and the PCB looks like a walk in the park compared to Minty's. If you want to make the PCB yourself, this is definitely the way to go.

Or if mp3 is to hich-tech for you, build a needle record player in Lego instead. No links included but a friend of mine did it 5th grade, I think you can make the plans yourself.

Tags: , ,

Baking is Making

Baking and cooking is certainly the most common form of DIY-project. Some see this as a necissary evil, some see it as an opportunity to be deliciously creative. Step out of the box and close the cookbook. Come up with something you think would b e delicious and make that. Or if that is a little too much on the wild side for you, find something you love and improve it. For example change half the fluid in your Swedish meatballs to beer or make a giant cake!

The guys over at Pimp my snack have taken the making of giant food stuff to the limit. How about a giant Bounty?

Damn, I can feel my arteries clogging up just looking at that thing. So much delicious saturated fat.

Extreme macro photography on a budget

 Photography is fun. It's all about being creative. Or actually it is not, since half of it now seems to be having the most megapixels or the best MTF-curve. In my opinion these things don't make better pictures. You still got the same motive no matter if it is 2 or 12 megapixels or if your lens responds better to higher frequencies. It's not for nothing, lenses such as LensBaby have become popular (take that MTF!). If we are going to play the equipment game, more interesting to me are stuff that lets you take new kinds of pictures or of subjects that you couldn't take before.

How would a picture of a skateboard jump look if it wasn't taken with a fisheye? Or how big would that eagle be in you photo if it wasn't taken with with a telephoto. And don't forget all the amazing pictures of Lennart Nilsson.

But buying all this equipment would put a serious dent in most peoples pockets. It is much more interesting, and cheaper to make the stuff yourself. One of the most popular hacks seems to be to build your own macro-lens. With a macro-lens, what you really need is a long tube and a long focal length lens. What you pretty much do is attach the tube on the camera body and attach the lens front side back on the tube. Sounds strange? Well, draw up the path of the light or trust someone who has done it.

There are several design out there already. Maybe the most famous is the Pringlescan design (the bonus is that you have to eat up the chips) but there are also alternative with extension tubes or converter rings.

Not as macro as a scanning tunneling microscopy (STM) but I'd go for it anyway. If you ever get the chance to try STM by the way, do it. It is pretty amazing to be able to see individual atoms.

Tags: photography, macro

Bottle jet pack

These japanese game shows sure are crazy. You know the normal bottle rocket, powered by water and compressed air. Everyone can make them. Easy wholesome fun. But surely you cannot only have one bottle rocket on a game show. That would be quite lame. So what to do. Well, if one bottle rocket is fun, 30 bottle rockets must be 30 times the fun. Now string them together and strap a poor guy to the rocket and you'll have to multiply the fun with his pain. Simple math...

Maybe not something I would dare to try myself. The control possibilities seem rather limited. Five euros to the guy that builds a working PID-controller for this thing!


Saturday, April 22, 2006

Opera 9 featuring widgets

 Linux have them, OS X have them, Yahoo have them and now also the excellent web browser Opera. Of course, I am talking about widgets, these small nifty toolboxes that you place anywhere on your computer screen or just bring up when you need them.

Opera 9 is first though with widgets in a browser (no, Firefox's extensions are not the same thing) and they seem to have great potential. There are radio widgets, wikipedia widgets, calculator widgets, comic widgets and so on. To jumpstart the widgetmaking, Opera has created a competition for the best widget. The big price is a sweet $6,000 computer. How about that? Now, go make a widget. Rumor is also that it is very easy to convert a Yahoo widget if you are already in that game.

Tags: ,

Maker Faire

For those not on the other side of the world, a great place to visit today or tomorrow would be the Maker Faire in San Mateo, California. It is a fair created by the makers of Make Magazine. They will hold workshops on everything from making neon lights to toy automata. 

Bring your old computers also and let them be part of their Knoppix veggie-oil-powered parallel computing cluster before being given away to people in more need than you. Come on, I'm sure you have several computers back in the closet that you are not using.

Customers taking over the creative process

For all the makers out there, doing stuff yourself is nothing new (that's pretty much what makes a maker a maker). Usually it means going to to the hardwarestore and firing up the blowtorch but companies are beginning to see the potential in the creativity of their customers.

On the 20th of April, there was a conference in Copenhagen called CustomerMade focused on this. CustomerMade is taking customization one step further. It's not about choosing the leather in your car it's about designing the car yourself theoretically speaking.

Since this being a Danish thing of course they had a speaker from Lego. He talked both about how they involved users in the process of creating the next version of Lego Mindstorm NXT (Wired wrote an excellent article about it a while ago) and how you can design your own LEGO kit. In a 3D program you build your legomodel out of all the available bricks. Then you and everyone else can buy the kit you designed. Very cool indead.

What's this all about

Damn, yet another blog. Aren't there enough of those already? So, what is this about then?

Well, yeah, there are probably enough blogs already. But this blog will be something totally different. Just read on to see why.

This blog will be all about all the crazy inventors and inventions in this world. It will especially be focused on the things you can make yourself. If you try to recreate any of the things publicized in this blog, beware, you are probably going hurt yourself. On the positive side, you will probably learn something while doing it.

Hey, this blog isn't totally different from all other blogs! You lied in writing!

Well, sue me!

Build your own picture frame PC

Heard about the new digital picture frames? Sure they are cool. But really, they only do so much. Plus you buy them ready made. Surely not anything for the MadMaker.

Why not build your own picture frame PC instead? On, Josh Hubbard has posted a picture series about how he made a picture frame PC out of a Via Mini-itx motherboard and, well, a picture frame.

This is an old project and Via has since released their much expected, and much delayed, Nano-itx motherboard. With a footprint of only 12x12cm I am sure an even smallar pictureframe can be build. If you custommake a heatsink you probably can get it much flatter too.

Tags: mini-itx, nano-itx