Contact Problems & Adjustments April 19

Throughout the class period Cailey and I continuously made adjustments to our lantern.

  Adjustment 1: We decided to change our LED from a red light to a white light because the white LED shines brighter.

Circuit with a red LED.

Circuit with a white LED.

 Adjustment 2: Since we switched our LED to a larger light, we need to make the hole on the case bigger. 

We tried drilling the case we had for the red LED but ended up ruining the wood (case on left). Therefore, we made a new case with a hole (3/16'' diameter) that is 1/8'' from the top of the case for the white LED (case on right).

 Adjustment 3: We initially thought that gluing a piece of metal to the bottom of the battery holder would be sufficient in transferring the current from the 2 AA batteries to the rest of the circuit. However, since the batteries have different nodes at the ends, the flat node didn't not have good contact with the metal sheet.

Picture taken by Cailey Stevens. A flat sheet of metal allows limited contact for the batteries.

 To increase the contact for the flat battery node, we folded one side of the metal sheet. This method worked. 

Picture taken by Cailey.

 Adjustment 4: The bottom of the battery holder was glued using a hot glue gun since it kept moving out of place.

The bottom of the battery holder was suppose to stay in place with the help of the tabs but this was not the case, as shown above.

Now that we had solved the battery contact problems in the battery holder, we needed to add the LED and the resistor, which would require soldering pieces or gluing metal sheets on the top lid for contact. Since we wanted our lantern to turn on when you push the case down, we needed to find a way to make a spring that would touch the batteries and ultimately complete the circuit (turns on the LED). We thought about and made small metal sheets to glue onto the lid to connect the LED wires and the resistor. Connecting the wires to the metal sheets would require us to solder them together. This method would be difficult and we anticipated that it might not work. We also tried coiling wire to glue onto the lid but this method would also require us to use the soldering gun to connect the LED, resistor, and coil. The main reason the coil did not work was because it did not provide a good contact with the batteries and the coil eventually stopped being a spring.

Different ways we tried making the spring/ battery contact for the LED and the resistor.

We finally came to the conclusion that if the LED wires simply touch the battery nodes, there would be no need of using a resistor to light up the lantern. Thus we removed the resistor from our circuit. We came up with the idea of rolling up the metal sheet to increase the contact with the batteries.

The LED was hot glued onto the case and the wires were soldered to the metal sheets.

And at last there is light!

Picture taken by Cailey.