Month: June 2017

Got the neat little case for the RPi “official” touchscreen and put that all together yesterday.  So I now have a nice little desktop APRS tracker.
Pretty nice, right?

Now I just need to figure out a way for APRSdroid to start at boot time instead of having to open an adb session and start it manually, and how to hook up a GPS to it, and the best way to hook it up to a radio so it’s not “crippled” by having to use APRS-IS.

The first may be fixable by writing a small “wrapper” program with the appropriate default activity to run at boot time.  The wrapper would then start APRSdroid.

The second may or may not already be fixed; I have a USB GPS puck hooked up, but since it won’t get a signal indoors, I’ll have to test that outside.

The third may be tricky, since either the Pi or the touchscreen is really sensitive to RF.  It may be something that can be solved by using a remote antenna, or I may have to find a better way to shield the assembly.

Optionally, I also need to add the open source maps that are supposed to work with this version of APRSdroid.

Anyway it’s been fun messing with this.  And yes, eventually I’ll take the protective wrap off the screen 🙂

LATER:  Added the open source map for Indiana.  Works fine.

That said, it’s a little frightening that you can get superuser in adb by simply typing “su”.  Boom, you’re root, no questions asked.  No wonder people are starting to look askance at the whole IoT thing.

So last night I was fiddling about and my Raspberry Pi 3, which has been sitting on the desk unused for awhile, caught my eye.  And I started thinking, hmm, what to do with the Pi.  And then I started thinking, I wonder if I could run Android on it.

Sure enough.

So then I started thinking, “OK, can I run APRSDroid on that?”

And the answer is, yes:

And it works, too:

I have to get dressed, gear up, and head out to WD9BSA shortly, so I’ll post how I did it later.  However, the trickiest part is figuring out how to start it (Android Things doesn’t act like a phone, so you don’t get icons on the main display).  Basically you have to do a

pm dump org.aprsdroid.app

and then you find that the android.intent.action.MAIN is mapped to the activity “.APRSdroid”, so that’s what you want to start it with:

rpi3:/ $ am start -n org.aprsdroid.app/.APRSdroid
Starting: Intent { cmp=org.aprsdroid.app/.APRSdroid }

See here for more complete instructions on how to install an APK under Android Things.

I thought I saw something somewhere about how to make an app start when you boot, but I can’t find it right now.  Again, later.

LATER:

Yeah, this is a great idea…except that I need to figure out how to force audio away from the HDMI port and to the headphone port, so I can hook the stupid thing up to a radio and use AFSK.  Apparently when you have the HDMI cable hooked up, the OS forces audio to HDMI, and there seems to be no simple way to fix that.  Perhaps the addition of the RPi “official” touchscreen will work around that; I don’t know yet.

Anyway, if you don’t mind using TCP to send your packets, this setup makes a nice static position beacon, without going through the effort to make a TNC out of the RPi — which, from what I’ve read, is a daunting task.

I may correspond with the APRSdroid author and see if he’s interested in tweaking the program a bit to make it more Android Things friendly — although it doesn’t seem like it could be much more friendly; it works, after all, it just doesn’t work the way I want it to, and that’s not his fault.  And it’s early days for me with Android Thing anyway; I never heard of it before yesterday so I guess I have a bit of research to do 🙂

MUCH LATER:

The official RPi touchscreen solves the HDMI audio problem.  I have successfully connected the RPi to my Baofeng BF-F8HP.

Last position:	2017-06-13 17:05:12 EDT (3m24s ago) 2017-06-13 17:05:12 EDT local time at Meridian Hills, United States [?]
Device:	Open Source: APRSdroid (app, Android)
Last path:	KC9YTJ-5>APDR13 via W9ICE-10,WIDE1*,qAR,W9SMJ-1

Two problems:

1. The touchscreen (or the PI itself; not sure which) is VERY SENSITIVE to RF, at least at 144.390MHz.  The screen goes kinda nuts when the Baofeng transmits.  Admittedly I’m using high power, so I could cut that back for testing.
2. I’m seeing the radio receive inbound packets, but they are not showing up in APRSdroid.

Problem one is simple enough, use a remote antenna or shield the Pi and display better.  Although even on low power, man, the screen is not happy.

Problem two is going to take some thought, as I don’t think there’s anything preventing APRSdroid from receiving the packets from the radio, unless maybe I need to enable a driver for the microphone or something.  I may simply try a USB audio dongle.  However, I’m looking at the verbose log and it’s clear the packets are being received; they’re just not being displayed.  So that may be related to why the touch screen suddenly stopped accepting touch input after the first transmission, and I’m using the physical mouse now 🙂

So I’ve turned VOX off on the radio so it doesn’t transmit, and now I’m just trying to see if the thing will receive and display packets.

Aha — the 3.5mm jack on the Pi is audio output only.  Well, $#!7.  Now I know what to do about that problem.

So here we are in Indiana, on the cusp of having a seamless DMR repeater network that would let you talk on 70cm throughout the state and around the world.

And now there’s a spat because one group of repeater trustees are championing the Brandmeister DMR system and another group is championing the older cBridge-dependent system.  And then there’s Crossroads, but who cares; I don’t.  I was perfectly happy with the Hoosier DMR setup.  Not that I get on much, but that’s another story; I don’t really like to talk.

Anyway, each group apparently has their reasons, each group is stubborn, and each group is now locking the other group out — even from Facebook discussion groups.  At least so far as I can tell; I’ve got likes and follows on both sides of the equation and all I know is that one side snorted that the other side locked them out, and now the other side is saying the same thing about the first side, and in point of fact, the Brandmeister Indiana Statewide group has been locked out of the cBridge — so from the DMR point of view, the state is now fragmented.

The section manager was just on Facebook asking if the Brandmeister group might consider adding TG 31189, which would have the effect of knitting things back together again on the statewide side.  31189 is apparently the Crossroads statewide TG, and it’s not being blocked by the cBridge.  The Brandmeister folks are against it for a couple of different reasons — one, why ask a thousand DMR users to reprogram their radios when 3118 would be perfectly fine if the Brandmeister repeaters weren’t being blocked from the cBridge, and two, “we hate Crossroads” (essentially what one of the trustees responded to the section manager).

The section manager is at least trying to deal with the situation where there is no longer a common DMR talkgroup for the ARES statewide net.  I appreciate that he’s trying to be proactive and at least provide a workaround for the current stalemate.  But I think (and I said this earlier today in a comment to a post that has (the post I mean) apparently been taken down) that the section manager has a role to play here that only someone who represents the entire Hoosier ham community can do.  He needs to call the warring sides to the table and they need to hammer out a working agreement that benefits all hams in the state.  And I admit that this isn’t a League problem, and it’s not technically his job, but what other ham radio organization has a statewide team and leader within the Hoosier ham community?  Who else will people listen to?  (And if people hate the League, as some people do for no particular reason that they can articulate, then fine, piss off and go play in your corners, and let the adults sort this out.)

Anyway…I have only about $300 invested in DMR handhelds (one VHF, one UHF), so I’m not terribly affected at this point.  I can always sell the handhelds or repurpose them for analog.  I’m not a big repeater guy anyway.

I’ll also acknowledge that a repeater owner can do pretty much anything he damn well pleases with his repeater — leave it open, lock it down to members only, or just shut it off and sow the wind (and probably get his repeater pair repo’ed by the Repeater Council, eventually).  But with great power also comes great responsibility.  If nobody is using the repeaters, what the hell good are they?  And in this case, if I could talk to someone in Fort Wayne the other day on a DMR handheld and I can’t today, where is my value in caring whether the DMR system continues to build or falls by the wayside?

While I’m not sanguine about the chances of the DMR network staying up in a real, balls-to-the-wall emergency — particularly given that a lot of DMR repeaters seem to get their Internet bandwidth via cellular wifi modems, and certainly not via hardened copper or fiber optic lines — the fact is that a DMR statewide talkgroup was a boon to the ARES organization, which prior to the rollout was pretty much stuck with an HF net on 80 meters.  DMR had the promise of bringing a lot more people onto the net, and was doing so, until this little dustup happened a week or so ago.  And that’s why I think the section manager has a dog in this fight — a pretty important dog, too, if we are all the public servants we claim to be when we sling slogans like “When all else fails, amateur radio works.”  The radios might work, but the humans behind them may not all be on the same page.

To top it all off, damn few people are using the repeaters anymore, analog, digital, name your favorite flavor.  Do you want people to use the repeaters?  Because this isn’t how you encourage them to do that.