Nerd alert! DH took apart an expensive Clearblure digital pregnancy test to see how it works...

[Crunchyside]

... It's got two thin test strips inside that look almost exactly like the cheap pregnancy test strips from Poundland. There are teeny weeny lights inside and a little sensor that detects whether a line has appeared or not and that is what tells the display whether to display positive or negative!

We did some extra research and basically the two strips contain different amounts of the chemical that reacts, this seems to be how it can estimate how many weeks you are.

See images - first one is with the strips attached and the second one shows it with the strips removed - the four little white rectangles on the left seem to be tiny LED lights, and the third picture just shows the display on the other side.

Basically it seems we are paying for a teeny tiny sensor to read whether a line has appeared on a test strip, rather than straining our eyes to see one! Other than that, it doesn't seem to be doing anything magical that the cheapo ones can't do.

Sorry if it looks yukky... this was a positive test that has been lying around in DHs office for about 4 months until he got round to dissecting it

Super nerdy MNers may be interested in the patent which explains how it works in more scientific detail!

Nerd, or intelligent person who takes an interest in science and has therefore proved yet again that brands are a ripoff?

BTW if that is a four months ago positive, I hope you are on track for a happy event in the summer.

Ooooh I like the nerdiness...have I read that right... Your DH has these tests lying around?

The one I used for my BPF was a double-use one - you could take the end off and put another strip in for a second go. When I threw the first (positive!) one away I clocked that all it was was a cheap one with a bit of extra kit!

Haha, yes, to clarify it was a positive test I took a few months ago and he wouldn't let me throw it in the bin until he'd taken it apart to see how it works! I think it got forgotten about on a shelf until he cleared out his man cave home office today.

There's slightly more to it than that, the digis will always produce the same amount of lines, thats why you aren't supposed to break them open. So it isn't just telling you if there is a line there, but reading the level of pigment in the line to give a result, much like the cbfm.

How interesting, it looks so complicated inside, it seems like a lot off effort and components for something you pee on and throw away
Elledouble I didn't realise they did double use ones
do they do one where you just keep sticking the strips in?

I dunno - I sent my partner to the shops to get me one and he came back with the expensive kind! I bet they could do a multiple use one but then they wouldn't be able to charge £10 a pop

Hey this is really fascinating, thanks for sharing, Crunchyside! I've been debating which ones to get

Not very environmentally friendly either throwing those away in landfill if they've got electronics inside them... they really should make them so that you can reuse the sensors and buy re-fillable strips :-(