It has been too long since we last spoke, our finest inventors have created a solution for your problem with customers leaving all their lights on while also helping with the electricity bill. We call it the Solar Rechargeable Lamp, during the day the solar panels will power the lamp whilst charging the batteries and a light dependent resistor (LDR) will prevent the lamp from turning on, while at night the batteries will be powering the lamp and the LDR won't be receiving enough light to prevent the lamp from turning on. We decided it would be best to use solar power because solar panels are cheap for how much power they can potentially generate.
Step 1: Tools Used
Starting from top left to bottom right.
- Needle nose pliers
- Wire cutters
- A pokey thing
- Soldering iron
- Hot glue gun
Step 2: Bill of Materials (BOM)
Items not included in BOM:
- 2x 4 slot AA battery holder
- 8x 1.25V AA solar rechargeable batteries
- 12VDC 1.65W fan
- 2x 6V 1.25W Solar Panels
Step 3: Schematic
- The solar panels are used to power the circuit and charge the batteries.
- The diode is used to protect the solar panels.
- The fan keeps the components cool.
- The batteries are to power the circuit.
- R1 is there to protect the LED from too much current.
- The LED is the light source.
- Q1 is used to amplify current.
- R2 is there to help R3.
- R3 is used to prevent the lamp to turn on during the day.
- The switch is used to manually turn off the lamp.
- Make a hole in the container to fit the fan, and on the opposite side make a hole for air flow.
- Get the fan and attach it over the hole, we used hot glue as the adhesive.
- You will need 18' of wiring, we took ours from a CAT6 cable.
- Get 16' of 2 separate colors of paracord and remove the innards so all you are left with is the sleeve.
- Take four 18' of wire, 2 will be white and be the negative leads and 2 will be different colors which are the positive leads, then sleeve them with the paracord.
- You will need something hollow to act as the lamp's arm, we split sugar cane and wired through that then sealed it up with bees wax.
- Route one of the paracords through the arm with 6" excess.
- Take 4" of something hollow and flexible and route the paracord through it.
- Seal the stiff and flexible arm together with wax.
- Get a flashlight reflector and secure a LED or few onto the reflector with wax, we used a 4 pin LED.
- Solder the white wire to the negative lead of the LED and the other wire to the positive, cover any exposed wire with electrical tape.
- Grab the other paracord and solder those leads to a SPST, we use a DPDT but it acts as a SPST.
- The dimensions of your perfboard should be 2.5" x 3.25".
- Hot glue both battery holsters to the center of the perfboard.
- Solder the negative lead of one holster to the others positive lead.
Start placing the components on the perfboard,
- Negative lead of LED connects to collector of BJT
- Positive lead of LED connects to R1
- R1 connects to negative of D1, fan, positive of battery, and R2
- R2 connects to base of BJT and R3
- Emitter of BJT connects to other lead of R3 and the SPST.
- The other end of the switch connects to the negative of the batteries, fan, and negative of solar panels.
- Positive of Solar panels will connects to positive of D1.
Step 5: Soldering
- Solder the negative of a solar panel to the others positive, the 2 solar panels are now in series.
- The black band of a diode dictates the negative side of the diode, you want to solder the other side of the diode to the unsoldered lead of the solar panel.
- Solder the lead close to the black band to positive lead of the fan, positive lead of batteries, R1 and R2.
- Solder the other end of R1 to the positive lead of LED.
- The negative of LED will be soldered to the collector of BJT.
- Solder emitter of BJT to a lead of LDR and a wire connected to the SPST.
- Solder the other lead of the LDR to the base of BJT and unsoldered lead of R2.
- The other wire of the SPST will be soldered onto the negative lead of the batteries, fan, and solar panels.
Step 6: Assembly
- After you finish soldering you will want to find a container to act as the lamp stand and hold the excess paracord, we used a cardboard box.
- Create two holes to fit the lamp and the switch, then hot glue the lamp and switch to the container.
- The solar panels will be glued, face down, to the bottom of the transparent container with the LDR right next to them and facing in the same direction.
- The perfboard will be glued to the bottom of the container lid.
- If the batteries and the solar panels touch when the container is closed, it will cause a short circuit, you will need to cover any exposed leads of the panels with electrical tape.
- Cover any exposed wires with heatshrink or electrical tape then you are donezo!
Step 7: BTW
You might want to fit some mesh onto the airflow holes to keep some dust out of the container. Placing anything above the holes to act as a hood would also be a good idea, and also sealing the lip of the container with hot glue to keep moisture out of the circuit. To use this circuit with your room lights is very easy, replace the LED with the lights, the solar panels and batteries will need to be higher wattage and should have equal voltage ratings.