This project is based on a 6V Solar Cell and constructed with two voltage regulators, one of 5V and other of 3.3V. The project is integrated inside a plastic box and in its exterior side is mounted the Solar Cell and a selectable switch to decide between 5V and 3.3V.

Step 1: Bill of Materials

1 ABS Plastic Enclosure for Arduino Board - Fits UNO or MEGA

1 Solar Panel 6 Volt DC @ 167mA 1 Watt 4.9x2.5x0.13 Inch 1 Standard Regulator 5 Volt 1 Amp 3 Pin 3+ Tab TO-220 1 Low Dropout Regulator 3.3 Volt 1.5A 3-Pin (3+Tab) TO-220 Rail 1 Arduino Uno Proto Shield (PCB only) 1 USB A Male To USB A Female 2.0 Cable Black 3 Feet 1 Toggle Switch (On-None-On) Single Pole Double Throw Solder Lug 5 Amp 250 Volt AC 28 Volt Panel Mount 2 0.1 uF 25 Volt 20% Ceramic Disc Capacitor 1 Capacitor Radial 1 uF 50 Volt 20% 85c 4x5x1.5mm

Step 2: Showing the Diagram

It's important that the diagram be followed carefully for avoiding errors when working in your project..

Step 3: Installing the Voltage Regulators

Installing the Voltage Regulators, you can see the details of each regulator either +5V or +3.3V. Also, note that you can observe each disc capacitor in the respective input of each regulator.

Step 4: Drilling of 1/4"

To make a hole of 1/4" in the plastic enclosure, you should use a drill bit of 1/4" so that you can install the toggle switch (On-none-On). That is, (3.3V-none-5V) install your select-able switch to decide between the two options that you have either 3.3V or 5V. Note that the hole should be done in the bottom part of your plastic enclosure.

Step 5: Preparing the Toggle Switch

To prepare the toggle switch, it is necessary to solder a wire in each pin of this so that you can connect it later to your solar cell and voltage regulators respectively

Step 6: Heat Shrink Tubing in the Toggle Switch

It's necessary to use heat shrink tubing of 1/8" so that you can separate completely the connections done in the step # 5. Though it's optional to use heat shrink tubing even any color, it's important to note that the wires with white heat shrink tubing are going to be connected to the voltage regulators while the red one to the positive terminal of your solar cell.

Step 7: Installing the Toggle Switch

Before installing the toggle switch by using the hole previously done in the bottom side of your plastic enclosure, insert the PCB prepared in the step # 3. Note that you are also connecting the wires with white heat shrink tubing to the inputs of the voltage regulators while you leave free the wire with red heat shrink tube to be connected later.

Step 8: Beginning to Install the Solar Cell

For installing the solar cell, it's necessary to use the wire with red heat shrink tube that you reserve for that purpose and it's placed between the wires with white heat shrink tubing. Also, before connecting that wire, cover the wires of your solar cell with black heat shrink tube of 1/4" while the positive terminal to be connected with heat shrink tube of 1/8".

Step 9: Connecting Negative Terminal of Solar Cell

For connecting the negative terminal of your solar cell, look for a GND to connect the black wire of the solar cell.

Step 10: Completing the Connections of the Solar Cell

For completing the connections of the solar cell, it's necessary to move the heat shrink tubing previously placed and fixed with your hair dryer.

Step 11: Preparing the USB-A Female Connector

For preparing the USB-A female connector, it's necessary to use the USB-A female to USB-A male cable and cut 1 foot of cable from the USB-A female connector. Next, remove the black plastic and the rest of material that covers the four wires into cable by cutting the white and green wires leaving the red and black only to be utilized.

Step 12: Using 1/4" Heat Shrink Tube

Use heat shrink tube of 1/4" to protect the metallic part exposed of the cable previously cut.

Step 13: Installing the USB-A Female Cable

For installing the USB-A female cable, it's necessary to connect the red wire of this to the output of the voltage regulators while the black one to GND.