LOPY as a Serial Terminal Server over LoRa

[geraldm]

Hi Everyone,

New to Pycom and first post.

Below is my issue in context.

I have an heavy rail application where I would like to monitor a serial string of data at 9600 bps from a remote track side box. This serial string is constant, therefore I would like to capture/sniff it only and via a look-up table find 4 specific ascii character string sets which is 4 alarm criteria, temperature high, track point fault, signal fault and supply fault.

I need to be able to send a summary alarm flag only initially of each criteria and then have the ability to interrogate the Signal box via the low speed terminal server to understand the exact route cause of the fault.

To the question:- Can the Lopy be used as a terminal server, use second serial port ( TX1/RX1 ) via proper level shifter as a means to connect to the signal box and allow Lopy to behave as a terminal server once an alarm is received at HQ, thus the user at HQ initiates a string via LoRa and turns the unit from sniffing the Serial port to becoming a Serial terminal Server for analysis. There are significant QTY of signal boxes track side, all are remote and none have any existing serial connection, thus a LoRa solution if possible is ideal.

This is a big call. I am trying to use one product lopy for all applications?

Regards

Gerald

[robert-hh]

@geraldm I do not know how the reliability demands of your application are. Two comments:

• LoRa is not a reliable transmission method, and it is mostly unidirectional. You can send short status information upstream, but you cannot rely on each message to arrive. But downstream messages are pretty limited. And you have to take care to provide a sufficient network coverage.
• The xxPy boards are not designed for highest availability. With a good power supply, it may work nicely for months, but may also fail for no obvious reason. So you have to add circuitry like an external watchdog to ensure a proper reset & reboot in case of a malfunction.