Thread: Bluetooth Intercom????

I will admit I am out of my depth here, but I hope that I can get some guidance from those on here that may know more about audio electronics than I do.

I am into Dragon Boat racing and for in-boat communications we traditionally have used a rowing style "Cox Box" intercom in which the sweep at the rear of the boat wears a microphone and belt control box, and a cable is strung along the interior of the boat which has speakers spaced along it. This cable can be cumbersome to transfer between boats and the loose cable in the boat is an entanglement hazard in a boat rollover. I have been trying to come up with a wireless solution to this issue.

I am trying to get a bluetooth solution working. I can source waterproof bluetooth speakers easily and bluetooth transmitters are available that have the required strength and range. My issue is getting a microphone to work into the bluetooth transmitter. The setup I have got to date is as follows:
- ebay microphone
- Kemo Preamplifier
- Bluetooth transmitter
- Bluetooth Speaker


(12v supply to Preamplifier not shown)

The bluetooth transmitter and speaker works as I can plug my phone into the transmitter and play music at a good volume at the speaker. The Preamplifier is doing its job as when I play music through the PreAmp (& then to the transmitter), the volume is amplified significantly through to the speaker. I cannot get a microphone to have any response at the speaker at all though. What am I missing here????

There is also the potential issue of delay through the bluetooth system which if present will scupper the whole proposal. Another option is a FM system, which I have got a prototype running. I would prefer bluetooth though as I think it would be less susceptible to interference??

As I said I am way out of my depth here and am trying to experiment and learn as I go. If I am full of the proverbial, just tell me!!!!

Cheers,
Chris