(first question on this board - n00b alert)

I'm on a second iteration of a small autonomous project which logs changes in magnetism. It consists of just:

Espruino board

Lipo battery

HMC5883L magnetometer

Battery and charger on the bottom, Espruino on top of that, and magnetometer soldered to the top of the Espruino.

Its all very thin and discrete, which it must remain for this project.

I have ordered some large heat shrink wrap thinking this will fine for weatherproofing it. For this iteration I am happy to rip off the wrap to get to the data after say, a month.

As I come to solder this stuff up, I am now starting to ask myself :

a) is wrapping it in heat seal going to break something?
b) will the magnetometer be affected by the surrounding electronics? 
c) are there any other issues I should consider?

Thanks for any remarks, pointers - or general advice about my approach which you are willing to share.

  • 1
    \$\begingroup\$ Well, you have questions that you ask of yourself so, what about questions you might want to direct to this bigger audience? \$\endgroup\$
    – Andy aka
    Commented Nov 16, 2015 at 9:38
  • \$\begingroup\$ if it doesn't need to look professional and only needs to last a month or so just use a foof container: \$\endgroup\$ Commented Nov 16, 2015 at 10:41

1 Answer 1


I see why you are using heat shrink in order to be able to position the magnetometer close to whatever you are measuring however have you made sure that you have got the right diameter heat shrink. By my experience you only get around a 40% decrease in diameter of the heat shrink tube when you, well, heat it. This means you can end up melting your heat shrink and it still not have it tight around your project. A cheep and easy alternative might be a snap lock bag? Apart from that I don't really see any issues. One method you could use to prevent the heat shrink breaking anything is hot gluing the whole project fairly tightly in place beforehand so that nothing can move. Just make sure that when you are heat shrinking you heat the whole thing gently and evenly.

  • \$\begingroup\$ Heat shrink just arrived. Looks a good fit to me. I'll get myself a hot glue gun. Thanks for your generally reassuring comments though, maybe I am spending too much time alone in this new direction I am taking and should get out and meet some other local makers. \$\endgroup\$
    – Cups
    Commented Nov 16, 2015 at 14:02

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