astromi.ch

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astromi.ch

Pure-Go drivers for Astromi.ch astronomy accessories.

mgpbox — MGPBox / MGPBox v2

A driver for the MGPBox: a combined GPS + weather (temperature / humidity / pressure / dewpoint) + dew-heater box. The v2 units use an FTDI FT231X USB-serial bridge (VID 0x0403, /dev/cu.usbserial-* / /dev/ttyUSB*) at 38400 8N1.

The box streams lines continuously, so the driver runs a background reader that keeps the latest snapshot; accessors return it. Hardware-validated against a live MGPBox v2 (FT231X, serial D30B0DP6).

box, err := mgpbox.Open()        // discover; or OpenPort(...), OpenBySerial("D30B0DP6")
if err != nil { log.Fatal(err) }
defer box.Close()
box.EnableMeteo()                // ensure meteo streaming is on

me, _ := box.Meteo()             // Temperature/Humidity/Pressure(hPa)/Dewpoint + dew heater
fx, _ := box.Fix()               // GPS lat/long/alt/sats/time (when it has a fix)
cal, _ := box.Calibration()      // after CalGet()

Commands: EnableMeteo/EnableGPSFix, GpsOn/GpsOff, CalGet, RebootGps, and Command(body) for anything else — e.g. Command("reboot"), Command("devicetype"), Command("calreset") (each wire command is :body*).

Line formats parsed: $PXDR (meteo; pressure in Pascal/bar normalised to hPa), $PCAL (calibration + MM/MG streaming flags), and standard NMEA GPS ($GPGGA/$GPGSA/$GPRMC). Banner / $PMTK / LOG lines are ignored.

CLI — mgpsnap

go build ./cmd/mgpsnap
./mgpsnap                 # discover, enable streaming, print a snapshot
./mgpsnap -watch 2s       # poll
./mgpsnap -list           # discover MGPBox ports (probes FTDI ports for MGPBox content)
./mgpsnap -raw            # also echo every raw line
./mgpsnap -port /dev/cu.usbserial-XXXX

Notes

• Shares FTDI's VID 0x0403 with the Unihedron SQM; Discover tells them apart by content (and the differing line speed — MGPBox 38400 vs SQM 115200), not by VID.
• On macOS, /dev/cu.* allows concurrent opens: quit any app holding the port first, or it will consume the stream.
• The reference implementation this was distilled from is mikefsq/gomgpbox.

License

MIT — see LICENSE.