Some Engineering of the Electronic Variety

Hello to all - just a walk up the Desert Path for a while..

I am assembling a new batch of GPS tracking Logger collars for our wildlife tracking and conservation efforts, and thought to share some the processes and fine work ( Not fine as in 'fine' but as in damn small !...)

The collar itself is made from industrial belting and riveted together, with a U-Bolt holding the collar ends together around the animals neck. At the base is a battery, with a 3 year life in this application, and at the top of the neck the GPS electronics is located. All are encapsulated in epoxy.

Below I show some pics of the assembly and tools used..

Assembled collars

Components Assembly with a microscope, rotating carousel for the PCB, and a Vacuum pencil to pick up the tiny components.

Solder paste is applied to the PCB using a brass shim stock stencil and squeegee- holes are drilled in the stencil on my CNC Router at each of the component pads. The hole diameter dictates the amount of paste deposited.

angled view with some idea of paste thickness - about 0.15mm

SMD parts placed onto the pasted positions.

Reflowing ( melting) the solder paste on a temp controlled hotplate.

Thermocouple in the center..

Solder reflowed..

The Vacuum Pencil - DIY using a plastic pen as the hand device, an adhesive dispenser tip as the sucker tip, and a fish tank air pump, with the pump reversed, as the vacuum source. A foot operated solenoid connects vacuum to the pen tip, or vents to ambient air to drop the part

Here is a small inductor vacuum attached to the pen tip.

Same view through the microscope..

That part, as is all the others on this board, is 0.9mm long x 0.3mm wide...

A batch of assembled tags - the RF module which does the radio communication with the logger and the Ranger tracking the animal, is fitted onto another small module containing gthe GPS, motion sensor ( which changes the 'beep' rate, giving indication of animal motion).

And then I also do repairs for the local Music retail shop in Town - PA systems, but mostly Guitar amplifiers, mixers, etc - just did this one, a very nice amp - fitted 4 new EL34's in the output stage and had to reset bias etc...Discovered this is a very nice knockoff off the Marshall TCT-100 of long ago. Really liked Marshall - Pity Jim is no longer around! Also liked Fender...Played keyboards in a rock band in my 'youth' and have 'fond' memories of lugging those valve amp heads and speaker cabinets in and out of gigs...

Only in the Tea Room...

And the Shaper has not been visited for over a week!!

Joe

Edited By Joseph Noci 1 on 17/09/2017 22:17:50

Edited By Joseph Noci 1 on 17/09/2017 22:18:36

Just as amazing as the shaper. I used a similar shaper as an apprentice and you could shift metal with it. I could never have thought of how you have improved it.

David

Glad to see you are using u-blox gps. Also used in a Bristol University project for tracking domestic cats, filmed for a tv documentary over here. What rf do you use?

Hi John.

The Ublox GPS we use has some warts, but is the only one that works with a supply voltage that varies from 3.6v down to 1.6volts - as we us a lithium battery - single cell - that's what it has to be!

The RF micro we use is one from ONsemi - an 8052 based uP, with a very nice RF transceiver, all in one chip. This one can work from 50MHz to 1.2GHz.

The tag has to be really reliable and foolproof - once encapsulated its hard to change anything, and once fitted to an animal, very traumatic to said beast to recover and fix....

I saw that documentary on the cats - fascinating!

The Shaper is calling...

Joe

This is a bit OT, but I would like to know how do you remove the collars at the 'end of life', or is the animal stuck with the thing until it dies? (I ask because we have a dog which was abandoned after its owner died. It had caught its collar on a tree stump, and was stuck there trying to get escape for several days. The cuts inflicted to its neck were invested with maggots when we found it - it survived after treatment)

Sad Story about the Dog -

In our application the collars are fitted so the animals can be tracked and monitored. The data that the collar electronics provides the researcher includes logged GPS positions of the animals travels, as well as battery condition. Once we determine that the battery is on its last 25% of life, typically after 2-1/2 years, the animal will be tracked, located and darted to either fit a new collar, or if no longer required, the collar is removed and the animal freed.

Joe