cross-posted from: https://slrpnk.net/post/21637924

A box of really old TomToms (softball sized) appeared at a street market a year ago, two for a dollar. I doubt anyone was interested in any and I doubt the seller would bother to return with them. They were probably be wasted.

In principle, old TomToms could be used to feed a smartphone. If you use a smartphone for navigation, these components compete to suck the battery dry:

  • the color LCD
  • GPS radio receiver
  • WiFi¹
  • GSM¹

(1) only applies to Google boot-lickers who enable location tracking in order to avoid the wait to acquire satellites.

The GPS is a significant drain because it’s heavy on non-stop calculations, which generates heat (wasted energy), and the heat itself hits the battery even harder.

We can do better. TomToms with bluetooth tend to suppot NMEA (I think). So the old TomTom w/outdated maps could be used purely to get a fix using its own battery supply, which it then transmits over bluetooth. So you toss TT in your backpack. Disable the GPS on your smartphone and enable bluetooth. Bluetooth is like 1 tenth the energy consumption of GPS. Then you enable mock GPS in advanced settings and run a FOSS bluetooth app that serves as middleware to feed the mock location.

The problem: OSMand and Organic Maps are both incapable of using mock GPS locations. And even if they add the capability, it would only be in their recent version which has already left behind older phones. (edit: well Organic Maps is not that bad… their latest version supports AOS 5)

Refusing to support Google means using airplane mode with location svcs off and being wholly dependent on GPS. And for whatever reason it takes me around 20—30 min to get a fix despite being in a large major city; every time. This must make Google happy. The old TomToms were faster at getting a fix. IIRC, they would take 20—30″ only the first time but quickly got a fix after subsequent power cycles in the same area thereafter.

Smartphones have the sensors to do inertial nav if you calibrate a starting point. But the apps don’t have their shit together yet. I vaguely a recall a FOSS app doing inertial nav, but not too useful if it results in a mock location that OSMand cannot handle.

  • tasankovasara@sopuli.xyz
    0·
    3 days ago

    Hold on re the problem. I have a bluetooth gps in the car (and a magnetic antenna puck for it on the roof) and osmand certainly rocks with it when using an app called Bluetooth GNSS inbetween. The app is unfortunately long since abandoned and not on F-Droid, looks like APKPure and co. do have it up for grabs.

    • activistPnk@slrpnk.netOP
      1·
      2 days ago

      The middleware app you link to says this:

      Navigation apps that support the default Android Developer Option’s ‘mock location’ feature location source.

      I installed a similar FOSS middleware app (which apparently no longer exists):

      https://f-droid.org/en/packages/org.broeuschmeul.android.gps.bluetooth.provider/

      It worked as far as getting the fix via NMEA over bluetooth and sending the mock location to the kernel, but the problem is that OSMand and Organic Maps are not written to make use of it. What version of OSMand are you using? I am trapped on an old version because OSMand decided to leave those with pre-AOS7 devices in the dust. Maybe they added mock locations afterwards.

      • tasankovasara@sopuli.xyz
        2·
        24 hours ago

        I was using that on my previous phone, also stuck on the custom LineageOS build I had on it. Android 9 iirc? OSMand was the up-to-date version in any case. The phone I have now manages to hear satellites inside the car much better, so I haven’t used the Bluetooth arrangement any longer.

        I did now install Bluetooth GNSS again and will give it a try sometime!

  • atzanteol@sh.itjust.worksEnglish
    11·
    4 days ago

    only applies to Google boot-lickers who enable location tracking in order to avoid the wait to acquire satellites.

    🙄