The TI slient745 is a data terminal from 1975. This project connects a raspberry pi zero to it, and then when the terminal is activated it prints the current status of COVID19 infections rates.
When the terminal is switched on, the raspi connections to https://covid19api.com/
and fetches the latest statistics and sends them to the terminal.
The TI slient 745 has a port on the back for an external modem. This accepts UART at 300 baud and 7E1
The signals are inverted so an inverter is needed.
If the terminal is switched off, there is feedback from the TX to the RX line through the terminal itself, which can create a loop if you're doing something with this input data. So the inputs are gated with the DTR signal from the modem.
Additionally the DTR pin was connected to GPIO4 on the Raspberry pi. This acts as the signal which activates the printing.
Raspberry pi Zero W with latest raspian.
By default the uart serial console at /dev/ttyS0
doesn't work at 300 baud
So you need to add to /boot/config.txt
dtoverlay=pi3-miniuart-bt
To disable bluetooth on ttyAMA0
and use ttyAMA0
with the GPIO pins at the correct clock frequency.
Finally test with:
picocom -f n -d 7 -p 1 -b 300 -y e /dev/ttyAMA0
Requires python3
on your raspberry under user pi
$ git clone XX
$ python3 ti-covid/main.py