1.5V AA rechargeable lithium

[Tim Lamb]

Not the end of the world but those sensor beam senders/reflectors are prone to disruption from Spider webs!

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[Tim Streater]

When I've done some power measurements, I'll post here.

[Tim Streater]

No, Kodak (so-called) off Amazon - a box of 60 AAs for £12.99 (so, 21.65p each). Bought end of May last year, since then used 47 of them. Yes, that's roughly one per week, or two weeks for the pair in each sensor.

[Harry Bloomfield, Esq.]

[e-mail] brought next idea :

The same as my door and the limits have always worked very precisely. They use a multi-turn, quite fine threaded rod to operate the limit switches.

[Harry Bloomfield, Esq.]

Wireless saves the manufacturer money and makes installation easier, never mind the end customer. It can also earn extra in service visits, to replace batteries which the customer wasn't aware of.

[nothanks]

Thanks anyway. TBH I hadn't realised they were so cheap because when I looked at the price of a direct replacement for what's currently fitted it was much more than seemed reasonable. I think part of the reliability issue is having to use a reflector, so I've just ordered an active pair of TX/RX units (less than £10) and will run an LV cable around the door. Another job added to the list, but I guess a list that's infinity+1 long is not very different to one that's only infinity long ;-)

[Harry Bloomfield, Esq.]

Martin Brown explained :

Which does not work on the way down - if the closing door jams, the motor continues and the roll just unrolls as best it can, usually down the back of the roll if it's open to do that.

[Harry Bloomfield, Esq.]

Tim Streater has brought this to us :

The supplied manual should tell you. They generally make these things as adaptable as possible, to suit a wide range of applications.

[Tim Streater]

There is a small terminal block inside the sensor unit to which 3V DC could be supplied, rather than using the AAs. I don't like the idea of a flying lead, however, but I could externally mount such as this: