Garmin Varia Rearvue 820 Radar development

What's the point? Is it only for development? How will it work in real usage? Won't it connect via BT as well?

The goal is to collect lateral passing data and other vehicle statistics and share with city planners, transportation engineers, to better understand how the design of roads affects the way motorists pass cyclists. It doesn’t help a rider much during the ride, it’s post ride where riders can contribute data to make roads safer for all. About the new radar - it can connect via regular Bluetooth (LTE/Smart) without any of the lateral or vehicle size features, but that means the data field would need to manage the BT connection and parse the data directly. I’m working on decoding the BT data stream as Garmin only shares the official protocol with approved hardware developers (Wahoo, SRAM, etc…). I can only reliably get information about the closest car at the moment and only approach distance measurements, which means having to redo some of the speed calculations, which are done much better by the radar itself. The reason for this is that range data is reported in whole meters at about 8 readings per second, which means the rounding or truncation to the nearest meter causes weird fluctuations in speed. 

I wasn't asking about what's the goal of the DF. What's the point of doing that "hack" as a user? Will your users connect 2 or 3 phones to engage the BT connections just to be able to connect to the ANT from the DF? Doesn't sound very likely.

BTW I don't have a radar, but in some HR straps you can enable/disable certain features using the phone app. Like: whether it has 1 or 2 bluetooth connections or if ANT is enabled. Isn't there such an app for the radar?

See https://www.dcrainmaker.com/2025/01/the-begining-of-the-end-for-ant-wireless.html

and

https://developer.garmin.com/radar-data-ble/overview/

Yes, I feel like Ant+ is on its way out, especially since the new radar even if you do manage to connect it in Ant+ mode no longer populates the BikeRadar object correctly. See my separate bug report here:  BikeRadar object broken with Garmin Rearvue 820 

As far as the bluetooth developer program, I have applied twice to that program using my university email address (I am a professor), and never heard back from Garmin either time. The application form on the right just opens up an email with a template of the information you are supposed to provide in the email. Based on the questions, it certainly looks like they are not working with independent developers. You need to be a big company with a large user base for them to even acknowledge the email (I guess?). Or maybe I have just been unlucky with whoever is managing that email address? 

The new radar (the Garmin Varia RearVue 820) can connect via Secure Bluetooth, or regular Bluetooth LTE/Smart, or  or Ant+ to Edge devices. Once you have selected Secure Bluetooth (the default), there is no easy way to get it to connect again via Ant+. Even just removing the device from the list of sensors isn't enough. When you try to add the sensor again, you don't get a prompt of what mode you want to use. It just automatically connects again via Secure Bluetooth. The only phone app for connecting to the radar via bluetooth is the Garmin Varia app, and it does not have a way of controlling the radar connection mechanism either b/c it only uses Secure Bluetooth, there is no Ant+ option.

Regarding the workaround I described, it's just a workaround for people who have the new radar and still want to be able to save and view radar data. Garmin doesn't do that natively, you need an add on extension such as the one I created. If you are interested in the data, it's the only way at the moment to make things work with the new radar. I don't think it's realistic, but I figured it out and a few other people may be able to figure out / follow the steps to get it working. It's the best we can do until Garmin updates the firmware probably on a ALL devices with a new option for switching between Bluetooth and Ant+ as the connection mechanism. I think that is unnecessary, though, all they really need to do is provide us ConnectIQ developers with access to the data coming from a Bluetooth paired sensor. They have already done that with Bluetooth paired HR monitors through the heartrate field being populated. They may need to update the ConnectIQ SDK to make it possible to access the radar data. That's the purpose of my feature request. 

The new radar does connect via Bluetooth LTE/Smart (probably what you meant by BT), but you have to parse the packets coming across and Garmin does not document the packet format unless you are an approved third party ... they have an application form I've sent in twice and never even got an acknowledgement that they received my application. Based on the fields you fill out in the application form, that program is targeted at large hardware manufactures such as Wahoo or SRAM who have display units that want to communicate with the radar.

Interesting how Garmin enforces secure BT. I wonder if you take this radar that already switched to secure BT, and try to connect to another Garmin device, that you never connected it to. Even then it doesn't let you connect via ANT? And what happens when you try to connect it to an older device that doesn't support secure BT?

I suspect that's due to EU RED (see the link I posted to DC Rainmaker from about a year back).

"The core reason for this change is the European Union’s Radio Equipment Directive (simply called EU RED), which will ultimately take full effect next summer (it’s currently in a transitional phase). That directive covers a flotilla of different areas, but one of the most applicable pieces is that it requires authentication and encryption for wireless communications of personal information. Or, at the very least, it requires manufacturers to make you aware when data is being transmitted without such protections."

We are close to "next summer".

Currently I can only connect my watch with secure BLE to an HRM 200.  I've not tried the multiple phone thing so that may work, but it's like if secure is available, that's really your only option - no open connects for BLE or ANT in general

Sounds like the data you want is only available with BLE, so you'll ever see it with ANT.