1.5V AA rechargeable lithium

[Tim Streater]

I assume it's a mechanical switch to stop the door closing. But the control box won't run the motor unless it's getting a continuous OK from the sensor. I haven't tried this, but I assume the tip of your foot under the door edge as it closes is enough to stop it (in fact it reverses the motor and the door opens).

The sensor can be adjusted to be more/less sensitive; if over sensitive then what happens is the door descends and will suddenly (when part way down) stop and reverse.

First step is I'm going to measure the current both quiescent and when the door is moving to see if the figures match the spec. Ha, turns out my trusty little Radio Shack DVM bought in downtown NY 2 weeks before 9/11 doesn't do amps, so zeroth step is to rememdy that lack.

[Tim Streater]

I would have assumed that in standby the sensor and the control box communicate every (say) few seconds. They must be doing this because the control box beeps if it can't hearr the sensor, and won't run the door motor. I'd take that to be the standby state. When the door is moving, the sensor would power up whatever magic gubbins it has to detect an impact, and communicate constantly with the control box. I'd take that to be the operating state.

So the duty cycle varies with how much you use the doors, which realistically is not much.

Agreed which is shy a measurement is in order.

Not that I'm aware of.

[Tim Streater]

Thanks for that interesting contribution. The door slats do indeed "compress" as the door approaches being shut. But the door curtain touches the ground before closure is complete. Then one can see the compression taking effect, starting at the bottom and working up until the motor hestitates, and then unwinds the last few inches to lock the top of the door into position.

Last year I had the installers come out and do a check, being then already fed up with the battery life. I saw them do a safety test, as the door approached the ground the guy whacked the door from underneath (thus doing a bit compression) and the door reversed.

I guess it's also possible the it's the controller which can decide that the door is closed/open and tells the sensor to exit operating mode.

But what you say tells me I need to do extra current measurements, not just in quiescent/operating modes but:

1) Door open 2) Door closed 3) Door opening 4) Door closing

So I await a new DVA meter and will then proceed. Meanwhile I better go help SWMBO who is busy reglazing the greenhouse.

[nothanks]

My doors have the limit switches incorporated in the tubular motors. The only sensors are IR beams to check there's nothing in the way as the door comes down, and these are cabled back to the control box. It seems crazy to design-in battery-powered sensors when mains has to be available for the motors.

[Tim Streater]

Only if battery life is short. I don't mind changing a battery once a year.

[Harry Bloomfield, Esq.]

Tim Streater was thinking very hard :

That seems a bit excessive - two weeks. I don't know what type it is, but I would only expect them to use current, when triggered by an obstruction. Is there no facility to power them from the mains?

[Harry Bloomfield, Esq.]

Tim Streater was thinking very hard :

I use an IR beam across the door, with a mirror target at the far end. It operates from the door control supply and if it sees an obstruction, refuses to close, or if closing, reverses. The sensor cost less the £10 via ebay, from China, but is very well built.

Making it even more useful, I added an LED deep into the garage, visible through my cars windscreen, operated by the sensor. LED is on lit, when my car clears the door.

[Harry Bloomfield, Esq.]

on 05/05/2021, Tim Streater supposed :

Does it not make provision for direct wiring of sensors?

Could you not use a sensor relay to remove the power from the door motor.

[The Natural Philosopher]

A neat trick would be to have a pair of say 12v contacts made when the doo is closed to recharge the packs :-)

[Paul]

The battery life table says 180 days minimum, maybe 400 days in more reasonable usage conditions. LR6 AA battery.

14 days does not imply shitty batteries, it implies the unit needs service. The door must be stopped by the limit switches (magnet driven), not by the safety sensor. If the safety sensor stops the door when it hits the ground, the safety sensor is more likely to be left in a high power (radio running) state, leading to a drained battery. If using a "good battery", the expected battery life would jump from 14 days to 21 days, and still not make it to 180 days or 400 days. It won't have good battery life, until the limit switch issue is corrected. The unit must run correctly to start with, with the safety sensor out of the control path. Then, you add the safety sensor back in, so that if the door is stopped by an obstacle, the motor stops until the obstacle is cleared.

That document has the small version of the battery life table, on page 5. The transmitter has a fuller table.

At a start, while standing inside the garage, when the door is closed, the safety sensor LEDs should go out. Indicating that there's no fault condition.

The first document here, is easier on the eyes. Page 3 has a table of LED codes.

The door has a deadman mode, and the limit switches can be checked there. There's also some kind of auto-calibration, where it checks the limits.

Paul

[nothanks]

It's still poor or lazy design when mains is available and a short length of wire would solve the problem without needing to use batteries.

[Harry Bloomfield, Esq.]

The Natural Philosopher wrote on 08/05/2021 :

Like it :-)

[nothanks]

Mine is the same. However, one door works reliably but the sensor on the other door needs very precise alignment with the target and operation can be a bit flaky so I've been wondering whether to replace it. It's on the "some time" list because the garage is really a workshop and that door isn't needed, but if you'd recommend the one you bought it would be useful to have a link ...

[Harry Bloomfield, Esq.]

Tim Streater formulated on Wednesday :

I like TNP's solution. Small rechargeable, but have it make connection with a charger as the door closes. That would not be difficult to arrange and is almost fool proof.

[Joey]

I don't believe that all the owners of those doors are changing the battery every 2 weeks. Bet there is some setup problem.

[Harry Bloomfield, Esq.]

[e-mail] formulated on Saturday :

It was 2017, so no longer able to link to it. It ran on DC 10 to 24v, cost £4.86 GBP from ZHTY TECHNOLOGY LIMITED.

They are quite critical to aim, sensor and reflector both need to be mounted firmly.

[Harry Bloomfield, Esq.]

The Natural Philosopher used his keyboard to write :

Not the pound shop Kodak ones I hope?

[Martin Brown]

It is perhaps one of a handful of situations where a solar powered recharge of those puny AA cells might actually make sense. I am inclined to think he should name and shame the company making this crap.

A Watchman oil monitor manages about 5 years on 3xAA cells. I can see no reason why his door sensors should burn through their batteries so quickly apart from a systemic bad system design or a fault condition that leaves them in some sort of panic state.

A set of batteries in such a device should last a few months at worst and if they don't then they should be using larger batteries. Most electric garage doors have a stall current sensor to prevent harm to trapped objects and/or a failsafe stop when they hit the ground after the limit switch has failed. It might still dint a car roof though.

My PIR back door light lasts something like a year on 3xC cells with daily use 30s of 3W illumination on trigger - that is well designed.

[Tim Streater]

How should I know.

How should I know.

[Tim Streater]

The front cover of this doc shows a pic of the three elements involved:

1) The remotes - look exactly like mine 2) The sensor on the door - looks exactly like mine externally and internally (although badged as Birkdale) 3) Control unit - *doesn't* look like mine although it could I imagine be an older model.