RadRunner Plus Rebuild

[chuyskywalker]

Now that I've got the nuts-and-bolts figured out on logging the PR/CA/GPS data down, I need to get it mounted.

First, I've updated my wiring chart to include the rpi; a new 5v dcdc that can be shared between the pi, dashcam, and potentially other things down the line, I suppose.

I also need to upgrade the rear electronics storage area; the aliexpress dime-a-dozen controller bag was simply out of room for stuffing in wires and components, and tbh, I wasn't super happy with how haphazard it was.



So I picked up one of these custom made RadRunner bags specifically to fit that whole gap in the rear of the bike. This should give me a lot more room -- and it sure as heck does.

After modeling every hard component that needs to go in the back, I took some internal measures of the bag, mocked that out, and have now modeled up a two-part electronics holder that I can mount everything into and sandwich into the bag. And to top it all off, there will still even be room in the bag for my repair kit (spare tire, inflator, tools, zips & snips, etc).


It'll probably be another day or two of print-test-refine loop, but nothing really new is being added to the system, just got to get it all to fit better, and less jumbled, than before.

Finally, I'm going to take this opportunity to swap out to some thinner wire for signals/power going from the bag to the front -- 16awg was insanely overkill, especially now that I've measured all the power draw devices and found that not a single thing pulls more than 1A at whatever voltage it runs. Plus, most of the wires are signal wires.

 

[chuyskywalker]

Coming together nicely; got run all the new wires now.

 

[chuyskywalker]

I got it all mounted and stuffed in the bag. Still can fit an air pump, spare tire, tools, and even some handlebar jack stands.

I did find, however, that putting the GPS for the rPi inside that bag with all the other electronics was...unwise. It's odd; the LTE/GPS tracker I have has no issues getting signal and doing it's thing, but the rPi took >20m to get a GPS fix while the bike was outside in a very unobstructed location.

Doing a bit more research, it seems GPS's can be disrupted by being too near other electronics around -- so stuffed into a bag with a computer, another gps, a few DCDC converters and a bunch of signal wires was...perhaps not the best environment. Sadly, I couldn't just pull it out because I'd shortened the USB cable. Oops.

But, that did lead me down the route of researching and learning about all the myriad number of ublox GPS receivers that are on the market and that I had the most basic possible, a generation-or-two-ago version. Totally usable for what a lot of people do with them (turn them into time servers), but there's better out there.

I ended up with BN-808 which is a more recent ublox 8 series chip (so it can get coords from multiple satellite systems concurrently). Additionally, this particular one has some flash memory and, critically, a built in battery for some RTC handling. I also learned how to turn on ublox's Assist Autonomous. (My layman's understanding: most GPS data is considered only valid for about 30 minutes or so; the 8 series chips can use previous data for something like 30 hours? It extends it a lot). This feature apparently will help get a lock much faster if I've been out for a ride and, say, stop for lunch.

Most importantly, though, I remodeled the rear lightbar carrier on the bike to accommodate a camera mount (to clean that up) and to also hold the GPS unit externally from the bike away from the RF noise part I was hosting in the bag.


This mid-line section analysis shows where the GPS nestles in, it's a screw-cap holding it down, and that the container (as well as the camera mount) both just "slot it" to the light bar carrier. Bolt the light bar on top and it locks everything down. Let's me take the camera/gps off if I need to work on them are replace them with a different "module".





And booooooy howdy does it work well. Even inside my apartment, it can grab a lock within 30 seconds or so.

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The last mystery to work out is that, sometimes, the OLED display can get...offset? Like, all the characters will be shifted down-and-right 15 pixels, but then the ones that would be offscreen wrap around to the top/left side. I'm not really sure what's causing that, and I don't have quite enough electronics experience to make educated guesses. So far it's usually gone away in a few minutes, and it hasn't affected the log file recording, so I'm not gonna get too hung up on that.

 

[chuyskywalker]

Got some photos of the finished setup today:




Along with the camera/gps mount; and here's the other side of the bag.



It's worth noting that I installed by bag in a ... unique way. Firstly, I could not figure out the "triple d-rings" for the life of me. I understand double d-rings; but these straps had three? Regardless, I wanted something a bit more stout. As such, inside the bag, there is a 3d printed plate with some re-inforcing ally tubes all zip tied together to create a solid top-plate. That top plate is then zip tied onto the rear-rack, under the extended seat. Makes for a super stable setup, and really snugs the whole thing up.



The four corners on each plate zip the ally tubes in place, the plates were CA glued together, and the other holes are spaces to allow for zips to hit the structural bars on the rear rack of the bike. It's pretty much rock solid.

You can see them, but I also 3D printed some grommets for passing all the wires through, since the bag has no openings other than the zipper.