This traffic-light clock was designed to help my daughter understand when she can get out of bed in the morning.

• Red - go back to bed
• Yellow - almost time, play in your bed if you wish
• Green - you can get up now

It has a simple design and a customizable schedule that can be programmed from the web interface. This clock uses Python3 to control the GPIO Pins on the Raspberry Pi Zero and also run the simple web server. This guide will give you all the software, inluding the OpenSCAD 3D model for the case, to allow you to create one of your own. Just supply the hardware, print the case, and load the software.

• Rasberry Pi Zero W V1.1 https://amzn.to/2YNBUNQ
• Low Voltage Labs Traffic Light https://amzn.to/2MVWmtl
• Micro SDCard https://amzn.to/3rnInvc

• Familiarity with Raspberry Pi
• SSH into a computer
• Basic soldering
• Basic command line experience
• 3D printing

You may be able to get by without soldering, but I soldered the wires onto my board. I did not solder into the traffic light device. I used GPIO spots GND/17/27/22 and wires that are 40mm long. You can use 14/15/18/GND too, and you will not have to rotate the light 180 degrees. If you change GPIO pins, you must update the monitor.py file with the new locations:

# GPIO Pin Numbers
g_io = 17
r_io = 27
y_io = 22

Once soldered, put the traffic lights onto the wires. With the lights facing towards the USB/HDMI ports, insert the wires, in sequence left to right, into the traffic light. While slightly pushing down, twist the traffic light 180 degrees, facing away from the ports. Next, place the PI Zero into the base of the case. Fit the traffic light through the hole in the top/lid part of the case, and then snap the top/lid down onto the base. Then, gently press the LEDs into the holes on the front. Once it is securely in place, fit the back of the light tower into place to secure the traffic light in the tower.

1. Download the latest image for your pi at www.raspberrypi.org

2. Use software, such as Etcher, to burn the image onto the SDCard

3. Re-insert the SDCard into your computer (where you burned the image) and browse to the /boot directory on the card

4. Create an empty file called ssh

5. Create a file called wpa_supplicant.conf. It should look like this:

country=US
update_config=1
ctrl_interface=/var/run/wpa_supplicant

network={
 scan_ssid=1
 ssid="YOUR_NETWORK_SSID"
 psk="your_password"
}

Be sure to use your SSID (Wifi network name) and password for your network.

Now put the SDCard into the pi and turn it on. When it comes online, it will have SSH enabled. If it does not connect, be sure you have the SSID (wireless name) and PSK (wireless password) correct. Without HDMI and keyboard, you will have to find the device on your network. You need the IP address to log in and set it up.

SSH into the machine, using raspberry as the default password

#ssh pi@ip_address
#example:
ssh [email protected]

Make sure to fully update your pi

sudo apt update
sudo apt -y upgrade

Install Pip and Git

sudo apt -y install python3-pip git

Clone this repo

https://github.com/ralphyz/color_clock.git

Install the required Python modules

cd color_clock
pip -r install requirements.txt

Schedule the program to run when the unit is rebooted:

crontab -l > mycron && echo "@reboot /usr/bin/python3 /home/pi/color_clock/monitor.py 2>/dev/null" >> mycron && crontab mycron && rm mycron
crontab -l > mycron && echo "@reboot /usr/bin/python3 /home/pi/color_clock/app.py 2>/dev/null" >> mycron && crontab mycron && rm mycron

Reboot to start the color clock!

sudo reboot

Once the pi reboots, you should be able to browse to the web server in any browser by typing in the IP Address. From the page that loads, you can touch a LED to enable that color. When a color is enabled and it is not the scheduled time for that color, the "Temporary Override" button will turn on. You can click it off, or you can select a different LED.

You may also select the Schedule Tab, and set the schedule for the light changes.

I hope this small project helps someone else. It was fun to write, and fun to see my daughter use. Also, please change your pi's password.