I’ve been frustrated with the RTL 510. Not that it does not function well but I simply could not hear the audible beep from my 1030 when a vehicle approached. There have been mNY posts on the forum about the alert not being heard. I’m definitely on the old side of life and my hearing is poor. I wrote in a previous post that I had a possible solution to try out and I finally got around to working on it. I’m now able to easily hear the alerts because I’m wearing a single tiny Bluetooth earbud which gets the Varia alert tone from a Bluetooth transmitter board that has a microphone input. The case with the board attaches to the bottom of the Garmin mount for easy installing and removing. The microphone is mounted right under the 1030's speaker.This is the first prototype and I have the Bluetooth board getting power from cell phone charger in my top tube bag. The next version I may try mounting a 3.7 volt battery under the case. The board draws very little power and a battery would probably last 50 hours at least. The charger will last far longer.
I’ve tried it out on about 10 rides and it has worked very well. I had at first set the Varia alert tone to the double tone but found that the single tone was very audible. I hope Garmin will allow the alert tone to sent by Bluetooth when designing the next series of bike computers. Anyone interested in the parts needed to assemble one of these, let me know. So, far I have a lot of money involved in this project. $2.40 for the earbud and $3.85 for the Bluetooth board. The plastic I had from other projects.