Monday, August 14, 2017

Assembling injection moulded Mesh Extenders

After various delays on various fronts, we now have in our possession enough components to assemble 40 Mesh Extenders, sufficient for the remaining activities for the Vanuatu Pilot.

Yesterday, the RFD900+ radios, antennae and Mesh Extender PCBs arrived:

 We already had the injection-moulded housings on hand (in the boxes behind the radios and PCBs):

First step of assembly is to fit the reverse SMA bulk-head connectors to the cases, and also install the o-rings.  While not particularly glamorous, this represents some number of hours of work to do.  Karthik, a work placement student, has been placed with us over the next few months, and gets to be the lucky one to do this task:

 The first afternoon's work, we have 16 units with seals and 2 of the 3 RSMA leads in place:

After these have been all prepared, we will then proceed with getting the firmware  on the PCBs, and radios and bulk storage fitted.

Our original plan was to use microSD cards, as they are lower power consumption than USB memory sticks, and probably handle power loss better than memory sticks.  However, there is a problem with the kernel driver for the microSD card interface, which we have yet to resolve, so we are probably going to stick with USB memory sticks for now. 

Fortunately we were able to get the USB port working in the Mesh Extenders, after a bunch of earlier problems with signal integrity of the USB data traces.

The only side effect is that we probably won't be able to reliably run these units on solar without a battery connected -- we'll find out for sure as we proceed with testing.

No comments:

Post a Comment