discussion / Biologging  / 27 March 2024

Waterproofing DIY VHF transmitter

Hi everyone,
I plan on tracking roe deer fawns for one to two weeks (checking for mortality).
We want to use lightweight VHF transmitters that should fall off after a couple weeks 
and can be reused. I just got my first PERDIX VHF Transmitter Circuit Boards - 20mm and will run them on a coin cell.

Do you have any ideas or tutorials on how to waterproof them without encapsulated them in epoxy resin?

Maybe with heat shrink tubing? They just have to be out there for a couple of weeks and I want to reuse them (change the battery).

@alex_rogers How did you do your snapperGPS Tests?

Greeting from Austria,
Robin 




Hi Robin

what about a 3d printer case?

Cheers

Virgil

The only reliable waterproofing method we've found without fully encapsulating is a bolted clam shell design with gasket or oring.

It's possible with 3d prints but tricky requiring specific types of printers, settings or surface treatments.

Easier to use a machined or off the shelf enclosure.

Hi

yes no all type of printers and materials are suitable. SLA 3dprinter will be a better choice. I used the Tough 1500 from Formlabs for 3d printed some tags, for example a turtle tag (picture below)  

You probably need to reinforce were the screws are going to attach the case to the collar because this resin can crak if tigh too hard.

As Brett said, you need a gasket or o'ring with the screw cap. Another method is to seal the cap with the resin but you need a new case everytime you want to change the battery.

Hi Robin,

I've used these transmitters and they are great. One thing to note is that, whatever you do, use some adhesive silicone to cover the entire reed switch first, as they are pretty sensitive and can be fairly easily damaged. If you are looking for something quick and simple, and you don't think it'll get bashed around a lot, you could consider some waterproof tape (e.g. https://www.amazon.com.au/T-Rex-285988-Ferociously-Strong-Waterproof/dp/B07CJ268PK?th=1). A layer top and bottom should just about do it. You could also add some heatshrink for extra protection. Also, you could wedge some carbon fiber sheeting (e.g. https://tinyurl.com/29uy295n) on either side to give it a lot more strength, noting that it's conductive, so be careful with the circuit and battery. 

Happy to discuss...

Cheers,

Rob