Hello! Today you'll build a LED controller that allows you to change the color of your lights over the internet. It runs on a Raspberry Pi and controls LED strips with some electronics that you'll be soldering together.
Before you start, make sure you have all the parts:
- LED Strip
- Protoboard (green board)
- PWM Driver (blue board)
- 3 transistors
- 2 pin connector
- 4 pin male male header
- 5 pin male male header
- 5 pin female male header
- DC barrel jack
- Some wire
You will also need the following parts which aren't provided with the kit:
- Raspberry Pi
- 12V 2A power supply
Take the PWM driver, protoboard, 5 and 4 pin male male headers from the kit. Solder the 5 pin header into the left side of the PWM driver, where it says GND OE SCL SDA VCC V+ (make sure the labels are on the RIGHT of the header). This will connect the PWM driver to the Raspberry Pi over I2C. Next, solder the 4 pin header just under the 0 1 2 3 labels, on the PWM row. These will provide the output PWM signal for the transistors.
Assemble the PWM driver to the protoboard: place the left topmost pin (GND) onto the protoboard in position C14. The last pin (V+) should be on C08. Solder the PWM driver to the protoboard.
Now take your 5 pin male female header and assembled protoboard with the PWM driver. You'll need to solder the header half way into the QRSTU row 17 position. Make sure that it's half the way in so that you could hook up wires to it on the underside of the PCB.
Then you'll need to connect this header to the PWM driver. V+ goes to the Raspberry Pi pin 1, SDA goes to pin 3, SCL goes to pin 5, and GND goes to pin 9.
Take the 2 pin connector and bend the pins under it a little bit closer together. Place it in the protoboard near the bottom left and solder it in place.
Next, add a ground wire that starts from the 2 pin connector. You'll need to strip a significant chunk of the wire and add solder to it.
You'll need to take 3 transistors and some wire.
We'll need to get a bit creative with this one. Place the 3 transistors on the protoboard, with the flat metalic surface closest to the pwm driver. The text should be facing you. Now bend them as shown in the picture below:
The goal is to reduce how much soldering is required. After bending the transistors, solder them in place, and connect the rigthmost pin to a central ground wire.
For this you'll need to remove the male male header from the LED strip. It has a slightly different pitch so normal headers don't work.
Now place it just under the pins you bent from the transistors, and solder them together. Each middle pin of the transistor should be connected to a pin of this header. The last pin of the header should be connected to the 12v source on the 2 pin connector.
As a final soldering stage, solder a small wire between the ground of the Pi and the ground of the LED power supply.
You'll need to connect the gate of the transistor to the PWM output pins of the PWM driver. First, cut a few short wires. Then, carefully solder them to each PWM output pin and transistor gate (leftermost pin of transistor).
Make sure that there are no shorts on the board. We're working with both 5v and 12v on the same board, so a mistake can be quite costly. Make sure that your board is layed out like this:
After completing the inspection, cover up the board with duct tape or electrical tape.
** Please note that during the workshop, your SD cards will come with all of this prepared. This is for reference. **
Make sure you have a Pi with a recent version of Raspbian (all 2017 versions work out of the box). It has to have python3.4 or newer, and python3-smbus installed.
To check if you have the right version of Python, just type python3 into the console. You should see the following output:
$ python3
Python 3.4.2 (default, Oct 19 2014, 13:31:11)
[GCC 4.9.1] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> Push ctrl + d to escape.
You will also need I2C to be enabled. To do this, you need to use raspi-config:
sudo raspi-config
> 7 Advanced Options
> A7 I2C
> YesFinally, clone and install this project onto your Pi:
git clone https://github.com/sasha42/LED-controller.git
cd LED-controller
pip install -r requirements.txtYou should now be able to run the server! Type sudo python3 server.py, and you'll see the following output:
LEDs are initialised
Server is listening
Your LEDS are now controllale over http://your-pi-ip/ 🎉 !
Try it from your computer, your phone or any other modern device. You can also connect directly over websockets to ws://your-pi-pi/ws.
There are many ways to have something run on boot on a Pi. In this tutorial we will be using crontab.
sudo crontab -e
# append to crontab
@reboot /usr/bin/python /home/pi/LED-Controller/server.py &Your Pi will now start the LED controller on next reboot automatically.
use ngrok