Solar Powered Square Light
Introduction: Solar Powered Square Light
Hey Guys what's up.
So here's something flashy and cool.
A Square shaped Solar Light which completely made from scratch.
The goal for making this was simple, I wanted to make an emergency light powerful enough for daily use. (To light up a certain area of my home during blackouts)
LEDs are all powered by a 2600mAh 3.7V Li-ion cell, I've also added a TP4056 Li-ion charging IC in this setup, and the LEDs are all driven by an AO4406 N channel Mosfet IC.
Also, this light contains a Dusk to Dawn feature which means when we plug the power IN for charging, the Main LED Light turns OFF and when we plug the charger out, it turns back ON.
this feature is essential for using this light outside with a solar panel connected, we dont have to turn ON/OFF this light daily, the solar panel will trigger this light during the day and night time automatically.
This Instructables is about the whole built process of this light setup, so let's get started!
Supplies
* Custom PCB
* 3V 1W LEDs 2835 Package
* TP4056 IC
* AO4406 Mosfet IC (N Channel)
* 1K Resistors
* 20K Resistor
* 100K Resistor
* AO3401 Mosfet (P Channel)
* Diode M7
* Type C Port
* Battery Li-ion 3.7V 2600mAh
* UC2515 Connectors
* 3D Printed Parts
Step 1: PROLOGUE
So this is how everything started, I made an emergency light last year by using a few LED strips connected with a Li-ion cell and an LED Driver.
The goal was to prepare a functional Emergency light that can be used daily in order to counter power outages, the place where I live is infamous for daily power cuts for a couple of hours.
This light worked properly and had an overall backup of 5-6 hours which was pretty sweet however because the LED setup was completely makeshift, it didnt lasted long so I decided to make a proper light by preparing a square PCB that contains LEDs with a simple LED Driving Mosfet, the system will be powered by Li-ion Cell and for charging the Li-ion cell I've added a Li-ion Charging IC that controls the overcharge and indication for charging.
The body will be made from PLA.
Step 2: SCHEMATIC
Here's the schematic I prepared for the mainboard.
It contains mainly three parts, the LED Section, Mosfet Driver, and the TP4056 Li-ion Charging section.
Firstly there are a total of 36 LEDs that are all connected in parallel. each led is of 3V and 1W which means all these LEDs combined draw 36W of power but it's not ideal to provide these LEDs that much power all at once, they will burn up so Here's what I did, I added a Mosfet IC (AO4406) and used a 20K Resistor on the gate of this FET, this limited the current down to 2.7A. 267
We can control this FET with a Microcontroller and drop more current by providing the Gate a PWM signal of 50% duty cycle. (instead of making this Pin HIGH, we can limit the current by providing it signal of 100 or even 50 by using the analogWrite function)
Then there's the TP4056 Section that consists of the TP4056 setup, 1K resistor is added with its Set Pin in order to configure the charging current to 1A, if we reduce the resistance value, the charging current will also decrease.
TP4056 also has an important feature that consists of two indication LEDs, During the battery charging, RED LED will glow but when the battery reached 4.2V, the RED LED will turn off and Blue LED will Glow.
USB Type C port is being used to power the TP4056 and charge the battery.
I've also added a P-channel mosfet between the battery and VCC of the system.
There's a resistor that keeps the mosfet ON as it is connected with GND, but I also added the Charging side positive terminal with the mosfet gate so when the charger plugs in, the mosfet gets OFF and the Load that is being powered by it shuts down, this feature is also known as DUSK to Dawn and its pretty commonly used in Solar based Lights and streetlights. when the solar panel stops getting power (night time) that triggers the mosfet and turns ON the power, when the sun comes up and solar power feeds power, the mosfet turns OFF and the light turns OFF as well.
I made this schematic by following the above things I mentioned and finalizing it. 267