Pen Spring AAA Compartment

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InstructionsExternal Components:2 pen springs (5 × 15mm or longer). Preferably low pitch and thick shiny wire to minimise electrical resistance. 1 strip of conductive metal (20 × 12 × 0.5mm or smaller). 2 nodes of small junction box (18 × 15mm for both)1 printed BODYOptional 1 printed JACKETEquipment:PliersScrewdriver for junction boxSand-paperAssembly: Use pliers to straighten springs so that there is enough spring to apply pressure on the batteries (10mm or more coil left) but there is enough straight to poke through the internal holes to feed into the junction box. Sand the ends of the coils and the straight sections (which will be electrical contacts) to get rid of potential insulating coating, in order to minimise resistance. With the springs through the spring holes, bend the straights up out of the box cavity and poke them into the junction box above, then push the junction box down into the cavity. Poke the wires (observing polarity) of what you're powering through the external wire holes into the junction box, and tighten the screws down. You may wish to solder instead. Sand the side of the strip which will touch the battery ends to minimise resistance. Put the metal strip into slot at the back. You may wish to glue it in place, but be careful not to get glue over where the batteries will touch. Due to the fact that pen springs are mostly clockwise-wound, the spring on the right will probably push against the side more than the left spring will. If this happens, I recommend that side be positive, so that the bump on the positive end of that battery can be hooked inside that coil.The debossed circles should allow rub-safe marking of polarity with marker pen. Insert batteries:Put the front end of the battery into the front end of its slot, observing electrical polarity.Push the battery forwards until it clears the back lip, then push the battery down and back onto the metal strip. repeat for the next one, the other way roundYou may find that the spring kinks against the battery. Shortening the coil might help.If the insertion is stiff against the plastic, it should loosen with use. The JACKET, if you choose to use it, should slide over the BODY either way round, for some protection. You will need to trim down the plastic screw shrowds of the junction box.