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Build it

The Kit

The kit should look like this:

And contains:

  • A small bag containing 28 pin header strips, arduino header plugs, a PS/2 connector and a capacitor.
  • Some antistatic sponge containing a 14-pin socket and a programmed ATTINY24 Microcontroller.
  • A FIGKeys 1.1 PCB (this and the sponge all go in an antistatic bag).

I think it's best to leave the components in their bags until you need each one, don’t just tip them out, or at the very least put them in two different trays so they don’t get confused.

If you’re new to soldering, I’d STRONGLY advise you build it with a friend or parent, to help you with checking the circuit and to share the excitement with as you turn it on for the first time and see it work!!! FIGkeys is simple to build, as easy as some Lego® kits, but mistakes can be made and are harder to fix.

Setting Up

The next stage is to make sure you have the equipment you need to construct FIGkeys set up properly:


  1. Make sure you have a sponge for the soldering iron - and make sure it’s damp (not dripping).
  2. Turn on the soldering iron. For my temperature-controlled one, I turn it to about 3/4 of the way, otherwise just turn it on. Make sure the soldering iron is securely positioned, I wouldn’t leave it lying on the workbench; I’d put it on a mount and make sure the mount isn’t going to tip up.
  3. Get the rest of the equipment you need:
    1. A small 2-3mm wide flat-head screwdriver for levering out ICs.
    2. A fine-tipped pair of pliars.
    3. A wire cutter for snipping the component legs.
    4. A solder sucker (in case you make a mistake, which you probably will, since I sometimes do!)
    5. A decent amount of solder. I use lead-free silver solder: Ag 5%, Sn 95.5%, Cu 0.5%. I buy it from Maplin, a consumer electronics store in the UK.
    6. Possibly some extra lighting.
  4. For Testing the board, you’ll need some additional equipment
    1. A multimeter. I have a cheap one from Maplin. The only feature we’ll use is the short-circuit tester, the buzzer.
    2. A Standard USB A-B cable.
    3. A USB power source, for testing purposes I strongly advise using a USB power adapter, that plugs into mains as it is less of a loss than a computer if you have made a serious error.
    4. A Phono lead. (I assume most people have several in the house). An audio phono lead will do as long as it has phono plugs at both ends. Phono to scart is OK as long as you check the direction of the video is correct.

General Soldering Principles

The basic principle is this: solder from the lowest components to the highest ones. That’s because I’m assuming you don’t have any special PCBs clamps so you want to position the circuit in a stable way while you solder and the best way to do that is to solder components from lowest to highest.

Familiarise yourself with the basic soldering guide. There's some good tutorials at Lady Ada, except you really, really do pronounce it as SOLD-er in the UK (the wikipedia entry says it's "/ˈsɒldə(r)/ "). There's also a wonderful soldering guide from the UK which doesn't suffer from pronunciation advice: http://www.kpsec.freeuk.com/solder.htm.

Soldering FIGkeys 1.1

There aren't many steps to soldering FIGkeys.

  1. First, solder the socket for U1, which is the lowest component. Remember to leave the ATTINY24 chip in the antistatic sponge.
    1. Insert the socket so that the notch at one end of the socket points to the left and so that all the pins go through. If it falls out when you turn it up-side down, you may find that you can use something to hold it in place as you turn it but don’t use sticky-tape as it’ll melt during soldering. Instead use a piece of thin stiff plastic or your screwdriver and then slide it out before soldering.
    2. Solder in a corner pin and then the opposite corner pin of each socket. This will anchor the whole socket in place so you can solder the rest with ease

    3. Then solder in the other pins.
  2. Next solder in the capacitor (C1). The legs should go nicely into the holes for C1, splay them apart by 45º on the other side before doing the actual soldering. After soldering in C1, clip the legs to about 1mm.
  3. Next, solder in the header pins on FIGnition. These are soldered on the top-side of FIGnition. First use a screwdriver to remove the existing FIGnition chips from your FIGnition so that they won't be damaged during soldering. You will need to break the header pins into 2x 8-pin sections and 2x 6-pin sections. The header pins should be soldered so they will line up with the header sockets. The easiest way to do this is to fit the head pins into the corresponding rows on the FIGkeys PCB [diagram], aligned to the rows marked "FIGNITION CONN" and then fit FIGnition onto the tops of the header pins. Solder the ends of the headers first to anchor them in place and then solder the rest of the pins.

  4. Next solder in the headers. Connect the headers to the header pins on FIGnition and then turn FIGnition upside down and place the FIGkeys PCB on top so that the header socket pins go through. They should align with the rows marked "FIGNITION CONN". A before, solder the ends of the headers first to anchor them in place and then solder the rest of the pins. You will need to be careful to keep them straight.
  5. Next solder in the PS/2 Connector. Note: There is a small mistake on the first PCB batch, which means the PS/2 connector itself must be angled slightly before soldering it in. (See diagram above). The best way to correctly solder the PS/2 Connector is to insert the PS/2 connector in the FIGkeys PCB and then connect FIGnition to FIGkeys and adjust the angle of the PS/2 connector so that the headers can fit tightly. You will need to keep the PS/2 connector in place while you solder the first pin (I soldered one of the smaller ones) and then you can solder the rest. Be patient when soldering the anchoring pads, you will need a lot of solder and it will heat up more slowly.

FIGKeys is now complete! Before you can use it, you'll need to test it first :-) !



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