Ethernet for serial data.
Posted: Sat Jan 14, 2023 6:31 pm
Given the inaccuracy of network time because of latency, variable server access, it is better to use a GPS module, and a Psion Organiser could be used to make an accurate time server on a LAN, probably as good as a Tier 1 NTP server, based on NMEA RMC with a 10 Hz report rate.
What method is best for converting between serial data and ethernet packets? It's likely that more tools than GPS modules can use such a thing, so I think there may be several good methods.
A Raspberry Pi might be ideal, and fast, but it's still a sledgehammer to crack a nut. Machine code on an Organiser might be a better way to make the packets (and parse them), so maybe the problem is reducible to converting a serial byte to an Ethernet byte (and vice versa) with minimal hardware with an RJ45 socket and enough 'brain' to set an address range and static IP via serial commands.
Any answer must be easy, otherwise it would be better to use the most available PC to get NMEA data directly via serial data and use a local time server based on software for other machines on a LAN to connect to, but he idea is NOT to have to do that because an Organiser might be a way to do it efficiently and independently of any other machine.
Given that Bluetooth is ideal for getting serial NMEA data over a distance of several tens of metres, a Bluetooth module that converts serial to ethernet is a very tempting notion because it would make it very easy to find somewhere to put each end of the system and not have any cable layout to do. I don't know if a serial-over-Bluetooth widget exists that has an RJ45 socket for use on a LAN exists, but it might be the best possible answer if it does, even if it means not using an Organiser in the data path, but having the Organiser inserted between a GPS module and a serial-to-Bluetooth widget does present interesting possibilities even if it's not used as part of ethernet packet handling...
What method is best for converting between serial data and ethernet packets? It's likely that more tools than GPS modules can use such a thing, so I think there may be several good methods.
A Raspberry Pi might be ideal, and fast, but it's still a sledgehammer to crack a nut. Machine code on an Organiser might be a better way to make the packets (and parse them), so maybe the problem is reducible to converting a serial byte to an Ethernet byte (and vice versa) with minimal hardware with an RJ45 socket and enough 'brain' to set an address range and static IP via serial commands.
Any answer must be easy, otherwise it would be better to use the most available PC to get NMEA data directly via serial data and use a local time server based on software for other machines on a LAN to connect to, but he idea is NOT to have to do that because an Organiser might be a way to do it efficiently and independently of any other machine.
Given that Bluetooth is ideal for getting serial NMEA data over a distance of several tens of metres, a Bluetooth module that converts serial to ethernet is a very tempting notion because it would make it very easy to find somewhere to put each end of the system and not have any cable layout to do. I don't know if a serial-over-Bluetooth widget exists that has an RJ45 socket for use on a LAN exists, but it might be the best possible answer if it does, even if it means not using an Organiser in the data path, but having the Organiser inserted between a GPS module and a serial-to-Bluetooth widget does present interesting possibilities even if it's not used as part of ethernet packet handling...