Gadget design, robotics, hacks, DIY technology and more.

For a long time now, I wanted to have a soldering fumes extractor. Until now I have been using a small fan but I wanted something more appropriate, something that would filter the fumes instead of just moving them away.

Some days ago, I decided I had to build a fumes extractor. I had a broken humidifier that I found in the garbage so I took it apart and used its pieces to build the extractor.

Materials

• An old humidifier
• Some assorted crimp connectors
• Some zip ties
• A rubber band
• A two positions switch

Tools

• A set of files
• A hacksaw or rotary tool
• A drill
• A diagonal cutter

Getting it done

The first step when building something from a broken appliance is obviously to take it apart and go trough the parts in order to find how you could put the together in order to achieve your goal. In my case, I required the suction fan, the air filter (which is actually a sort of sponge used to provide as much surface area as possible for the water to easily evaporate), the base, and the power wire. I also ended up cutting a piece of the plastic casing that has a grid on it so I can attach the filter and put it in front of the air exhaust.

Then, it is a matter of cutting, drilling, filing, sanding and fitting together until you have the desired shape and function. I really like to use zip ties for binding things together since they are cheap, strong and can be undone (sort of) easily.

As for the electrical part, the can motor had three coils that, when energized, drive the motor shaft at three different speeds. Since I do not have the need for that much speed control, I used a three positions switching order to control it. I connected the main switch lead to the mains power and the other two leads to the first (slowest) and third (fastest) coils. Then I connected the ground and the mains power to the motor as required and voila. When the switch is in one position, the fan turn at the slowest speed (since the first coil i energized) and when the switch goes the other way, the fan spins at full speed (since the third coil gets energized). Finally, the the switch is at the middle position, all the coils are disconnected and the fan sits still.

Also, since I do not have a crimper, I used a diagonal cutter to crimp all the conenctors (that go to the switch). Using a diagonal cutter for this purpose can be tricky since, if you apply too much presure, you may end up cutting the conenctor, or if you apply too little presure, then the cable may slip away from the connector. As it can be seen in the picture to the right, crimping with a diagonal cutter leaves a very distinctive mark on the connectors.

I found a nice breadboard in McGill’s garbage a while ago and decided to convert it into an electronics bench. My main goal was to have a powerful power supply with regulated outputs combined with a breadboard and some useful connectors so I can build circuit prototypes easily. Also, I needed a new bench power supply since mine was lost in the Lunar Excavator shipment.

Materials

• A nice breadboard found in the garbage
• A computer power supply
• An ATX motherboard power connector
• Two LEDs with resistors for current limiting
• A switch
• Some cables

Putting it Together

I wanted to build a modular system so I can replace the pieces easily, especially the power supply (since it comes from an old computer and may not work for very long).

I connected a switch and two LEDs (actually, my switch comes with an integrated light so I used only one LED) to the PS ON, 5V SB, and PWR OK pins so I can have an indicator of the power supply (PS) being plugged-in (D1) and another for the PS being turned ON (D2). The diagram below illustrates the connections.

I also connected the 12, 5, 3.3, 0, -5, and -12 V lines to the bottom-left banana connectors in order to have easy access to the power lines. Now, I can connect any ATX power supply to the box and it will work, which makes replacing a defective power supply very easy.

After making the electrical connections, the switch and LED(s) have to be mounted to the box by drilling appropriate holes.

This was a fairly easy build, with the only difficult part being to find the appropriate materials in the garbage.

I may add a USB hub or some USB connectors as well in order to have more ways of connecting things to the box.

I found a big potentiometer in McGill‘s garbage (universities’ garbage is pretty good). When I found it, it was very dirty and its body was badly bent. Fortunately, I managed to put it back together and now it is shiny and fully functional (as shiny and functional as a pot can be).

Some Specs:
It is a 400 Ohms potentiometer made out of an array of thin metal hexagons and a contact point that moves along them. The number of hexagons in between one end of the array and the moving contact is proportional to the potentiometer’s resistance. It is roughly 50 cm long and I bet it can handle lots of current.