Introduction: DIY Solar Powered Automatic Street Lighting
My house is located in rural area, so the street in front of my house is completely dark when there is no light at all. So here i made a solar powered street light that automatically turns on at sunset and off at sunrise. It uses the solar panel as the light sensor. When there is no light, the lamp turns on and vice versa.
Step 1: Component and Schematic
The component you'll need :
1. an XL4015 5A buck step down converter. This will be used as a solar charge controller. Set the output at 4.2V.
2. an NPN Transistor, i used BD139
3. an N Channel MOSFET, i used IRFZ44N
4. a high current diode, i used 6A diode
5. a 3 watts LED and a heatsink
6. 2 resistors, 1K and 100K Ohms.
7. a Solar Panel. i used 3x10WP Monocrystalline solar panel.
8. a Battery. I used 10.000 mAh Lithium Polymer battery from broken power bank.
The schematic is very simple. When there's no light, no current output from the buck converter so the transistor switched off, and the MOSFET's gate is charged through the 100K Ohms resistor and its switched on and the LED is ON. When there's a light, there's a current from the buck converter charged the transistor base and it will switch on and the MOSFET's gate is connected to the ground through the transistor and it will switched off, so the LED is OFF.
Step 2: Mounting All the Component to the Pole
I made the light pole from cheap galvanized steel bars. The solar panel is mounted at the top of the pole facing north at 20º from the horizon.
The circuit fit perfectly inside the pole. I mount it to the pole with metal spacer.
For water/rain protection, i used a quacker can placed upside down covering the circuit and the battery.
Step 3: Testing
With this system, the battery can last from sunset at 6 pm to sunrise at 5.15 am everyday. It turns on and off automatically so i just left it unattended and it just works.