orlandocarnate / lcd_projects

Raspberry Pi I2C LCD 1602 projects using Python

CTA Bus Tracker using a Raspberry Pi and an I2C LCD 16x2

A CTA Bus Tracker LCD Display using CTA's Bus Tracker API, Python, Raspberry Pi 3, and I2C LCD 16x2 Display.

About

A CTA Bus Tracker app cta_tracker.py written in Python that displays information on a I2C LCD Display. This device displays:

• Current Time
• Route and Direction
• Stop Location
• Estimated time of arrival
• Final stop destination

CTA Bus Tracker API

I used CTA's Bus Tracker API to retrieve info about my local bus route and estimated arrival time at a specific bus stop. To get your own API key go to this link: https://www.transitchicago.com/developers/bustracker/

Installed Packages

Below are instructions on installing i2c-tools and python-smbus onto the Raspberry Pi OS: sudo apt-get install i2c-tools sudo apt-get install python-smbus

I found instructions on finding the I2C address at CircuitBasics.com

I also 3D printed a case for the LCD from Thingiverse

Notes

Parameters needed for the URL query string:

• key = API Key
• rt = Route
• stpid = Bus Stop id
• format = JSON

The response keys used:

• rtdir = Route direction
• des = last bus stop
• prdtm = Predicted time of arrival to bus stop stpid

Virtual Environment

• python3-venv https://www.techcoil.com/blog/how-to-use-python-3-virtual-environments-to-run-python-3-applications-on-your-raspberry-pi/
• https://docs.python.org/3/library/venv.html python3 -m venv ~/my_venv_folder

To activate the environment: source ~/my_venv_folder/bin/activate

ex install: pip install flask

To exit environment: deactivate

Example JSON response from the CTA Bus Tracker API

http://ctabustracker.com/bustime/api/v2/getpredictions?key=YOUR_API_KEY_HERE&rt=60&stpid=6339&format=json

{
	"bustime-response": {
		"prd": [
			{
				"tmstmp": "20200801 17:57",
				"typ": "A",
				"stpnm": "Blue Island & 15th Street",
				"stpid": "6339",
				"vid": "1663",
				"dstp": 16216,
				"rt": "60",
				"rtdd": "60",
				"rtdir": "Eastbound",
				"des": "Randolph/Harbor Dr",
				"prdtm": "20200801 18:19",
				"tablockid": "60 -205",
				"tatripid": "1032776",
				"dly": false,
				"prdctdn": "21",
				"zone": ""
			}
		]
	}
}

JSON Error Example

{
	"bustime-response": {
		"error": [
			{
				"stpid": "6339",
				"msg": "No arrival times"
			}
		]
	}
}