Bluetooth profile for Garmin Varia RTL515

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Sat, 08 Mar 2025 09:13:54 GMT

You can contact me, if you need any details. However, you should find all relevant profile information in this thread.

RE: Bluetooth profile for Garmin Varia RTL515

honza_81 — Sat, 08 Mar 2025 07:43:32 GMT

Hi Ed!

I just find this thread, because I want to do exactly the same thing. Just signalization unit for my bike. Did you make any progress with your project?

Jack

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Tue, 13 Dec 2022 21:24:09 GMT

The code that implements my findings above is here: https://github.com/Wunderfitz/harbour-tacho/blob/master/src/variaconnectivity.cpp Not that elegant, but works smoothly - and should be transferable to most Linux-based systems having BlueZ and Qt installed...

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Tue, 13 Dec 2022 20:07:57 GMT

That shouldn't be a big thing. What is your question?

Kind regards,

Walter

RE: Bluetooth profile for Garmin Varia RTL515

8559875 — Tue, 13 Dec 2022 15:45:22 GMT

I'm also considering writing my own code to graphically display the radar/threat data on a small OLED screen driven by a microcontroller (ESP32) with built-in wifi and BLE/BT. ie. this is not an app on a phone thing.

Please point me to the right direction to look for more info on how to read the Varia data.

thanks

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Mon, 08 Mar 2021 20:53:56 GMT

OK, measured several streets nearby, I'm now almost completely sure that these assumptions are correct. Byte 1 remained constant per car/motorcycle/bike, so that seems to be the threat ID on my device. Byte 2 also behaved exactly as in demo mode - measurements started somewhere between 130 and 140 m (and the LED starts flashing at about 80m distance). Byte 3 always returned the speed of cars in km/h that I expected on the respective street (I tested 30, 50, 70 and 100 km/h streets). Funny side effect was that most cars were above the maximum speed when they were far away and slowed down to the allowed maximum speed when they saw the light flashing on the sidewalk. :D

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Mon, 08 Mar 2021 14:24:26 GMT

Well, these answers are exactly the reason why I was writing the previous comment. My issue is that I can't confirm your observations for bytes 1 and 3 so far. As said, some field tests will follow, but especially the results for byte 3 are so much different from yours (all bits of the byte being used, value seems to be more or less threat speed in km/h), I'm wondering if I might even have a different device (firmware)...

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Mon, 08 Mar 2021 14:19:07 GMT

It's an app for Sailfish OS - mainly for personal use as I don't think that there are that many other people using this mobile OS and the RTL515. In the end, I would like to have an app that displays the current GPS speed side-by-side the threats and a battery status information. So it's not really a big project... ;)

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Mon, 08 Mar 2021 06:39:03 GMT

I alteady explained that iin my answers above, including the first four bits of byte 0. Just read all my answers and you should be fine.

RE: Bluetooth profile for Garmin Varia RTL515

Nikeow — Mon, 08 Mar 2021 03:11:40 GMT

Ygriega out of curiosity - what are your goals on this project?Is this for an Android App? (Since you say no to CIQ App and IOS App)

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Sun, 07 Mar 2021 22:40:03 GMT

Thanks again for the help. That motivated me to keep on experimenting... In the meantime I got the stream reading working properly on my device. :) The demo mode is really a great help! I still need to do some field tests next week, but from what I've seen so far in the demo mode and from walking around in my apartment, I have a slightly different interpretation of the data which I am getting.

Where I agree:

Packet length in bytes seems to be 1 + (threat amount * 3)
Byte 0 is probably some kind of packet identifier
Byte 2 (5,8,11...) is the distance to the threat. As the maximum range of the device is 140m according to the manual and the demo mode uses a maximum value of 143 I suppose that the unit is meters here. Moreover, it comes very close to the distances I measured in my apartment with real-life samples (OK, they were of course all <10 meters, but they were more or less accurate)

Where I disagree (or at least have questions ;)):

Byte 1 (4,7,10...) seems to remain constant per threat, so I suppose this one is the threat identifier
Byte 3 (6, 9, 12...) seems to be the either some kind of threat level or the threat speed. Using the demo mode I took the timestamp when my mobile received the respective packet (which is probably inaccurate, but may give an indication on average over all received packets for this threat) and if the assumption on the distance (unit in meters) is correct, the values in this byte come very close to a uint8 representation of the threat speed in km/h. On average, the value is always about 12% higher than what I would expect of a value in km/h which is a good enough approximation for me at least.

What are your thoughts on that? More updates will follow once I have time for field tests...

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Sun, 07 Mar 2021 09:31:33 GMT

And for me it's neither Garmin's App Store now Apple's App Store. :D But thanks for letting me know, will keep that in mind if I start developing for this platform.

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Sun, 07 Mar 2021 08:15:51 GMT

Ah, you are talking about Garmins App Store and I thought about Apples App Store ;-)

RE: Bluetooth profile for Garmin Varia RTL515

jim_m_58 — Sun, 07 Mar 2021 07:58:43 GMT

https://forums.garmin.com/developer/connect-iq/w/wiki/10/app-approval-exceptions

https://forums.garmin.com/developer/connect-iq/f/discussion/255421/app-approval-exception-rejected-app-again

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Sun, 07 Mar 2021 06:56:27 GMT

Why?

RE: Bluetooth profile for Garmin Varia RTL515

jim_m_58 — Sat, 06 Mar 2021 23:15:48 GMT

Remember, as mentioned before, there is a very strong chance that if you use radar that the app will be rejected in the app store.

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Sat, 06 Mar 2021 19:50:16 GMT

Thanks for confirming that the service is the right one! In this case I'm definitely doing something wrong accessing the data via BlueZ and D-Bus (I'm on Linux). Didn't know about the demo mode, I obviously overlooked that in the manual. Seems to work smoothly - no longer walking around in my apartment to get threats. ;)

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Fri, 05 Mar 2021 22:34:59 GMT

Hi Ygriega,

the service UUID "6A4E3200-667B-11E3-949A-0800200C9A66" is correct. As mentioned above, you should get 1 + 3*i bytes, whereas it gets a bit more difficult in case, the stream needs to be splitted due to max. payload size of BLE.

Do you have your radar in demo-mode (6s power-on)? You should do that, to get some threats. I also had connected my Wahoo Elemnt Roam for debugging the information in parallel.

RE: Bluetooth profile for Garmin Varia RTL515

Nikeow — Fri, 05 Mar 2021 22:23:27 GMT

App Approval Exception (Rejected app again)

RE: Bluetooth profile for Garmin Varia RTL515

jim_m_58 — Fri, 05 Mar 2021 22:05:29 GMT

Using radar info can be cause for your app to be rejected for the app store.

https://forums.garmin.com/developer/connect-iq/w/wiki/10/app-approval-exceptions

RE: Bluetooth profile for Garmin Varia RTL515

Ygriega — Fri, 05 Mar 2021 21:30:24 GMT

Hi WaltGre,

thanks for the offer to contact you in case someone needs additional information. ;) I also want to create my own app using the radar data from my RTL515. However, I'm still struggling getting the data from the device (identified as 'RTL64894'). BLE connectivity seems to work properly - my mobile detects 3 GATT services:

Generic Attribute (UUID: 00001801-0000-1000-8000-00805f9b34fb)
Device Information (UUID: 0000180a-0000-1000-8000-00805f9b34fb)
? (UUID: 6a4e3200-667b-11e3-949a-0800200c9a66)

I'm getting some nice data about the device like the vendor name "Garmin" (what a surprise!) and some additional values that probably represent firmware revisions and other stuff using the characteristics underneath the 'Device Information' service. Moreover, I suppose the radar data is shared via the 3rd service, but here I only get a packet of 2 bytes length and no updates seem to be sent out if a threat is detected.

Do you have any hints what I might do wrong or what I need to do to get the radar data from the device? I have to say that I'm quite a newbie in the BLE field, so sorry in case the answer might be obvious.

Thanks in advance for any help!

RE: Bluetooth profile for Garmin Varia RTL515

WaltGre — Thu, 15 Oct 2020 17:42:10 GMT

Hi, thanks for the response. I wanted to connect the radar directly to the iPhone and/or Apple Watch (via Bluetooth). Actually reverse engineering was not sooo hard. However, Garmin could have saved my time by providing bluetooth profile information.

The profile is as described above in one of my posts (only valid for Bluetooth!). One addition: The first 4 bits of the first byte (byte0) should be used to recognize splitted payloads because for many multiple threats, the payload will be splitted (due to max. payload length of 20 bytes). Splitted payloads will have the same 4 bits, so they can be concatenated in your application.

At the end I struggeled with the idle mode of the Apple watch which can not be deactivated. However, the iPhone app provides notifications (in case of threats) which are sent to the watch (if iPhone display is off).

So, everything is now fine. If someone needs additional info, just contact me.

Kind regards,

Walter

RE: Bluetooth profile for Garmin Varia RTL515

Kurev — Wed, 14 Oct 2020 19:17:56 GMT

Via AntPlus API, you can use listener and in onMessage() you'll have the payload data. This works with sensors paired and connected to Garmin device.

For non-connected, you can connect yourself and get data via Ant API.

Or was this what you mean by data stream?

RE: Bluetooth profile for Garmin Varia RTL515

READINGDANCER — Wed, 14 Oct 2020 18:58:01 GMT

Hi @Kurev are you saying it is now possible to access the data stream via ANT+ within a Connect IQ app, I know 18 months ago this was not possible as I discussed it with Nick Kral. but I've not kept an eye on the API changes over the last year. If it is possible, I might re-visit my app idea 🙂

RE: Bluetooth profile for Garmin Varia RTL515

jim_m_58 — Mon, 05 Oct 2020 21:40:12 GMT

It's just an example of how things can be more complex than they first appear. Where having the profile helps.