This design is very straightforward and simple - all the materials that I used to build it cost about $10 as I bought all the components online.
Step 1: Materials
- Soldering Iron
- 9V Battery Snap Connector
- 9V Battery Clip
- Wire (6 in. max)
- 3 10mm white LEDs (Super Bright preferred), 28000 MCD
- 3 220 ohm Resistors
- Breadboard-layout solder board
- Velcro Strips
Step 2: Circuit Layout
Once all the components are on the board, secure them by either taping over the tops of them to make sure they stay in place, or bend the leads going through the board to 90 degree angles to ensure they won't slip out when the board is turned over for soldering.
Note: The beveled (or flat) edge of the LED is the cathode which goes to ground. If the LED is reversed it will not light.
Step 3: Soldering
Step 4: Overall Circuit Testing
Otherwise, analyze the circuit built on the solder board to ensure that current passes from the +V battery bus through a resistor, through the LED, and through the wire back to the -V bus back to the battery. If the soldering was a little rough there may be some cold solder joints or broken pads, which make breaks in the path for the current to travel. Ensure that the LEDs are facing the correct way with the beveled (or flat) edge going to the -V bus of the solder board.
Step 5: Battery Mounting
By attaching the 9V battery clip to the bottom with velcro, the 9V battery can be easily removed from the underside of the circuit board while still being stable enough to act as a base for the light source.
Step 6: The Final Product (and Miscellaneous Notes)
- If you do not buy a diffused LED it can be diffused by roughing up the surface of the LED down with sandpaper
- You can directly Velcro the battery to the bottom of the circuit board, bypassing the need for the clip. However, new Velcro will have to be applied with every new battery.
- If you bought a longer solder board than you need, feel free to cut off the excess. Either do this by laying out the circuit on the printed circuit board first, drawing where the cut point should be, and then cutting it off, or just be careful about your cuts when all the parts have been soldered on.
-If you would like to add more hours of operation, the 9V battery can be substituted for a AA battery clip (1.5V per battery, typically 4 AAs in series) - however this will only supply the circuit with +6v, which means the resistor needs to be lowered to 150 ohms instead of 220. The typical AA battery has a higher Amp-Hours rating than a 9V, which directly equates to a longer lasting light.
-If you would like to add more branches of LEDs on the overall circuit diagram, go ahead! Just make sure to mirror the existing architecture for the current path - +V Bus -> 220 ohm resistor -> LED -> Wire -> -V Bus. The only effect this will have on the overall circuit operation is that it will draw more current from the battery, lowering the overall hours of operation per battery.