Dynamo Harvester Bluetooth LE w/ proprietary BT profile

Hey,

that’s the feeling I got when having a look at the API—it looked more like what you described than what I would need in this case.

S&C should be working, I guess, I just haven’t tried it yet. But I read a post on a bulletin board where someone described how to use the Dynamo Harvester together with Locus Maps and it worked for him.

The ExtraSensors class looks good so far, although it would be better to have two altitude values to work with. The companion app for the device—according to the manufacturer—uses both the GPS altitude as well as the barometric altitude of the device, preferring the barometric value for accuracy reasons. I have yet to see the source code to see how exactly it assesses which value to use, though.

Temperature would be more of a nice-to-have feature and I would rather like to see the altitude work first, as it’s more important to me—although the temperature value would, of course, be interesting as well when using the live broadcast feature of Locus Map track recording. :)

I’m not sure which kind of altitude sensor it is. If it’s absolute, I guess that’s what the app uses GPS for: to calibrate the initial value. I think I have read that somewhere, too, but I cannot find it at the moment.

So did I understand you right that you would be willing to implement the profile for this special device into the core application? That would be awesome!

Hello,

fine. Secondary altitude should bring extra load to Locus, but such parameter should be needed really rarely (only in this case). So I may only offer direct implementing into Locus if I get specification for these profiles, but:

- received altitude will be set to only single "altitude" parameter that exists in "Location" class

- temperature will be set to "temperature" filed in extra container (usage of this parameter is anyway quite, well, ... it's only exported to GPX files, otherwise it's not visible in Locus).

So this is best I can offer for now :).

Locus Map already offers the usage of a smartphone’s barometric sensor—I guess you are solely using that one in case the smartphone has one? I tried to find a way to mock smartphone altitude sensor data by using the Dynamo Harvester’s data of the altitude sensor but could only find ways to mock gps coordinates; it doesn’t seem like other data can be mocked on actual devices, i.e., not Android virtual machines for development.

I will write to the manufacturer and ask then. What exactly would you need?

Barometric sensor is used when you allow it inside "Altitude manager" feature. Anyway barometric values are not stored, but instead directly used to modify elevation values.

About "what I need to know"

If I'm correct, then to read correctly any data over BTLE, it's needed to know UUID of certain characteristic and also structure of data.

- UUID is just a text that identify source

- by structure I mean - data are load as byte array (byte[]), so I need to know, what is inside

My name is Thomas and I am the developer of the Bluetooth firmware of the Dynamo Harvester. We would be glad to see support for our Dynamo Harvester in Locus Map. If you are intending to adapt the Locus Map software to the proprietary Dynamo Harvester Bluetooth profile we would give you all info you need and we would send you the Dynamo Harvester hardware for testing.

The Dynamo Harvester implements the CSC profile, of course, but this profile cannot carry high-resolution data of speed and distance; altitude is completely out of scope of this standard profile.

You would need to implement the following steps:

• Search for CSC sensors
• Check all CSC sensors for the availability of our proprietary profile
• If our profile is available, register notifications for this profile. Do not register or use the CSC profile, because our profile is a superset of CSC.
• With every notification you get the absolute number of dynamo events and the time of the last event. Additionally you get barometric altitude (not calibrated) and temperature.

What do you think? Does it make sense for Locus Map?

Good day Thomas,

I'm glad to see here someone qualified from this interesting project.

I also think that cooperation here should be really interesting and mainly useful. Locus is made mainly for hike and BIKE and number of users is quite high, so there definitely will be more interested users then "just" Patta who started this topic.

Anyway as I'm more basic BT developer, implementation is possible only with help from your side. So if you will be interested, please keep in mind that I'll have more questions in case, something won't work :).

So generally, if you may be able to give me some sample codes, I'll gladly add support directly into Locus.

Second question is anyway - what data Locus may get from your device, that will be useful for user and in cases they are not yet fully supported in Locus, how to handle with it. As I see on your page with specifications: https://www.be-on-bike.de/en/harvester/specifications.html , there exists:

- "distance" - Locus do not handle measured distance in any cases as distance is already measured from GPS coordinates

- "altitude" - here it may be interesting as correctly calibrated barometric altitude is a lot more precise that measured GPS altitude

- "temperature" - interesting parameter that Locus may record and export to GPX files

So, if I'm correctly, only interesting here is altitude value, which I'm not 100% sure if it worth it.

I’d love to see the increased accuracy that the barometer brings. I understand that including the dynamo’s speed date for increased accuracy especially in tunnels and so forth won’t be possible but I would very much like to have the altitude values of the DH included.