Zeroconf NMEA Wi-Fi interface for the iPad

For connecting serial devices (GPS, AIS, NMEA instruments...) to the iPad via 802.11b/g Wi-Fi, a lot of hardware interfaces exist on the market :

• Digi Connect Wi-SP Connect Wi-SP (Digi)
  
• NetCom 123 /423 / 823R WLAN Wifi Server (VSCom)
• PS110W (SENA)
• WiSER2400.IP (OTCWireless)
• SX-500 (Silex Technology)
• ATS-300 (Argus Technology)
• NPort W2150/2250 Plus (Moxa)
• WIPS IPS-101W, Wireless IP Serial Device Server (WApass Technology)
• AD-net
• SW111-M9V (ATAC Technology) ...
  

and more dedicated marine -but also more expensive products- such as :

• SEAMate 1A (Molgaard Marine House)
  
• iAIS / BOATraNET (Digital Yacht)
• iMux (Brookhouse)
• SeaSmart.net (Chetco Digital Instrument)
• SBox wifi (Sailmon)
  
• DMK Box (DMK Yacht Instruments)
• NMEA-2-WiFi (Comar Systems)
• MiniPlex-2Wi (Shipmodul)
  

But all these hardware interface use some manual configuration (web configuration via some Ethernet or Telnet/https/SSH interface, via specific utilities not cross-platform -Windows only-, via console), so no user-friendly way to connect your marine instruments directly to the iPad.

To allow the interface between a marine sensor and the iPad without any manual operator intervention, the Marine GeoGarage team has lead an experimentation using Zeroconf networking, which enables automatic discovery of devices on the iPad.

For that, we use a basic SoC (System on a Chip) AR2315 Atheros based Wi-Fi router (also used in the Marine GeoGarage AIS experimentation).

(see also Altop Tech SW1001T wireless serial server or Open-Mesh mini router)

• adding some RS-232 serial interface for direct connection to a NMEA0183 device
• developing an embedded software (under OpenWRT) to broadcast the received NMEA sentences to a specific iPad application implementing zeroconf protocole.

The result is an iPad universal application which allows to display via this hardware Wi-Fi router the direction and the strength of the wind from a wireless ultrasonic wind sensor :

Marine iWind experimental iPad weather app
(design © Marine GeoGarage

allowing real-time querying of historical data stored in memory)
connected with CV7SF sensor from LCJ Capteurs