Wind Instrument to Bluetooth

There are many different options in the Marine Electronics market for publishing your instrument wireless. Different vendor offer everything from, Ethernet, to proprietary wireless technology to Bluetooth. The leap to wireless for me is a very expensive leap. To buy one of these complete products will not be possible this year.

Full small vessel Wind/ Speed/Depth systems start around $1,100 and go upwards to $1,800 US

Alternatively there are hybrid systems that take a wired system and output wi-fi and bluetooth. Companies like ShipModul, Noland, Actisense, and Brookhouse offer Multiplexer that output these wireless signals. cost begins around $250 and go upwards to $700 US

There are also serial to bluetooth dongles that plug into a multiplexers serial port that enable this data transfer wirelessly for boat with existing wired multiplexers. Cost range for the dongle is from $50 to $85 US. Unfortunately for me I don't have a multiplexer.

As mention in previous posts, I have 2 instruments on-board, one of which is NMEA based (wind instrument). My winter project was to interface this wind device with Bluetooth. To start, I needed a bluetooth transmitter, something that would work with a DC power supply and eventually hook up with serial based data (outputted from the wind device). After a few web searches and a credit card, I purchased one of these devices. Approx 10$ CAN for the BT device

JY-MCU Bluetooth transmitter

Back side of board

From the vendor...

Serial Bluetooth RF Transceiver Module RS232 w/ Backplane Enable & State Pin

This small size Bluetooth TTL transceiver module allows your target device to both send or receive the TTL data via Bluetooth technology without connecting a serial cable to your computer. It's easy to use and completely encapsulated.

- TTL data transparent transfer between a host Bluetooth device.

- Works with any USB Bluetooth adapters.
- Default Baud Rate: 9600,8,1,n.
- Coverage up to 30ft.
- Built in antenna.
- Power input: +3.3VDC.
- Mini Size.
- TXD: Transmit Data (Data output pin for the UART),must be connect to the RXD of you device
- RXD: Receive Data (Data input pin for the UART),must be connect to the TXD of you device
- VCC,GND: power supply,between 3.6V~6.0V,Prohibit more than 7V,Otherwise, damage to device!
- State: Connection status output,when bluetooth is connect,output high,otherwise,output pulse(about 5Hz)
- ON/OFF: Power Control,when is low(default),power is open,when is high(not less than VCC-0.5V),power is close

Some of the challenges in using the Bluetooth transceiver are:

• Must regulate the voltage down from 12 volts (on boat) to 3 to 6 volts to supply power to the unit.
• Device accepts TTL based communication, so must convert serial to TTL
• Must program the unit and change the baud rate to 4800

Seen below, using a solderless breadboard, I created a small circuit using a 5 volt regulator, 4 capacitors and a RS232 Max (Serial to TTL).

The idea was copied from the following diagram which shows a circuit using serial, Max 232 TTL converter and a downstream TTL device (in my case, Bluetooth)

I'm waiting for a TTL programmer device to change the bluetooth baud rate before testing all this.


More to come at 11....