hardware: SG site installation needs rethinking

[jbrzusto]

There have been repeated failures from:

• a flooded Pelican case
• a GPS cable chewed through
• an overheating beaglebone due to poor heat transfer of computer inside box inside box inside box model, with the outer two boxes having additional heat-generating devices (funcubes, hub, battery)

New Approaches

• pelican case strapped to antenna mast 1m+ above ground, with portal facing ground
• portal sealed around cables with spongy foam
• lid-less beaglebone metal case installed inside Pelican case so gps cape has view of sky, removing need for external antenna (the GPS cape is sensitive enough to work through a few mm of plastic.
• USB cable left connected to beaglebone and emerging from Pelican case, with computer end protected by a short length of weather-proof plastic pipe and appropriate tape. Get longer USB cables if necessary
• funcubes weatherized and placed outside Pelican case in hot locales

Raspberry Pi Zero W approach

• each antenna gets its own RPi Z W, gps hat, RTLSDR radio dongle, packaged separately in a small, heat-conducting case with weatherproof BNC and power connectors
• each RPiZW powered separately but from the same DC/DC converter.
• each RPiZW is a WiFi hotspot, perhaps with pushbutton to activate
• data downloaded separately from each RPi.
• except for power and antenna mast, that makes each antenna system standalone, which would simplify replacement
• cheaper

[StuMackenzie]

Short-term steps for Motus staff:

1) A modification to the setup instructions online showing an example of the gnome placed outside of the box with instructions on changing the power cable and a fail-safe and convenient way to affix the gnome to the tripod/mast. I'll send you a picture of one of the Ontario ones which will do for now.

2) A post to sensorgnome and motus-wts lists advising users of the 'preferred' or safe setup linking to the revised instructions - especially in flood prone or coastal areas.

3) If we want to roll this out across our network, or at least at flood prone sites, we should source new power cables - preferably marine-grade with proper connections at either end and jerry-rigged with speaker wire. Woody could probably put these together cheaper and faster than we could. Dave, we just need to know the ideal length. They don't need to be high - waist or chest height would probably be ideal.

Compudata: should make an extedned power cable an available modification with at least 6-8' of marine-grade power cables. Dave can advise on a standard or ideal length.

[StuMackenzie]

In terms of field installation, all new builds should have the cable entry port opposite the handle coming out the bottom of the case. This way the handle can be used to affix the case to whatever you want, and the box can still be opened when in place.

[jbrzusto]

Does that leave enough room for everything to fit inside without overstressing cables?

[StuMackenzie]

Mike seems to think so, at least with RPi's. We're gonna try it on the next one.