code and setup to test 3 anchors and 1 tag decawave boards. Used Raspberry Pi 3B+

first_down.py

import json
import redis
import serial
import sys
import time

from art import text2art

if len(sys.argv) == 1:
    print("Please provide a numeric value for the first down")
    print("Example: python first_down.py 0.18")
    sys.exit()
try:
    first_down = float(sys.argv[1])
    print("Initial First Down is at {}".format(first_down))
except ValueError:
    print("Please provide a float value for the argument (first down)")
    print("Example: python first_down.py 0.18")
    sys.exit()

first_down_art = text2art(text="FIRST DOWN!", font="3d-diagonal")

# connect to redis on port 7001
r = redis.Redis(host='localhost', port=7001, db=0)

# connect to Decawave tag
DWM = serial.Serial(port="/dev/ttyACM0", baudrate=115200)
print("Connected to " + DWM.name)

# two carriage returns to initiate communication with Decawave tag
DWM.write("\r\r".encode())
print("Encode")
time.sleep(1)

# tell Decawave board to start sending data
# API referecen page 99 https://www.decawave.com/wp-content/uploads/2019/01/DWM1001-API-Guide-2.2.pdf
DWM.write("lec\r".encode())
print("Encode")
time.sleep(1)
try:
    while True:
        data = DWM.readline()
        if(data):
            print(data)
            # if the data includes locations for each anchor parse it
            if ("DIST".encode() in data and "AN0".encode() in data and "AN1".encode() in data and "AN2".encode() in data):
                data = data.replace("\r\n".encode(), "".encode())
                data = data.decode().split(",")
                if("DIST" in data):
                    anchor_number = int(data[data.index("DIST")+1])
                    for i in range(anchor_nummber):
                        pos_AN = {"id": data[data.index("AN"+str(i))+1],
                                  "x": data[data.index("AN"+str(i))+2],
                                  "y": data[data.index("AN"+str(i))+3],
                                  "z": data[data.index("AN"+str(i))+4],
                                  "dist": data[data.index("AN"+str(i))+5]}
                        pos_AN = json.dumps(pos_AN)
                        print(pos_AN)
                        r.set('AN'+str(i), pos_AN)
                # if there is position data for the tag
                if("POS" in data):
                    x_pos = data[data.index("POS")+1]
                    y_pos = data[data.index("POS")+2]
                    z_pos = data[data.index("POS")+3]
                    pos = {"x": x_pos,
                           "y": y_pos,
                           "z": z_pos}
                    pos = json.dumps(pos)
                    print(pos)
                    if float(x_pos) > first_down:
                        print(first_down_art)
                        first_down += 0.2
                        print("New first down is at {}".format(first_down))
                    r.set("pos", pos)
    DWM.write("\r".encode())
    DWM.close()

except KeyboardInterrupt:
    print("Stop")

requirements.txt

art==4.6
pkg-resource==0..0.0
pyserial==3.4
redis==3.4.1

run_redis_container.sh

#!/bin/bash

docker run --name redis -p 7001:6379 -d redis

up_and_running.sh

#!/bin/bash

# Used Hypriot OS 1.12.0 from
# https://github.com/hypriot/image-builder-rpi/releases/download/v1.12.0/hypriotos-rpi-v1.12.0.img.zip
# which includes python 3.8 by default and docker

# install vim editor and python 3 virtual environment tool
sudo apt-get install vim python3-env

# get pip so we can install python packages
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

# install pip
python get-pip.py

# create virtual environment for python packages (pyserial and redis)
python -m venv venv

# start python virtual environment
source venv/bin/activate

# install python dependencies/packages (pyserial and redis)
pip install -r requirements.txt

# pull redis docker image from dockerhub and start container exposing
# port 7001 on host to container's 6379 port (redis default)
./run_redis_container.sh

# start the script to listen to the Decawave tag
# ensure to pass a float (decimal) value for the inital first down location
python first_down.py 0.0