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#1
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Freezer door alarm
I've had several freezers with "door open" alarms but they've been all
been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? -- Mike Barnes |
#2
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Freezer door alarm
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#3
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Freezer door alarm
On Thu, 9 Apr 2009 09:38:36 +0100, Mike Barnes wrote:
Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? No cancel button? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. Don't be such a lazy B and buy "frost free" heaps of ****e then. The important thing *is* the temperature if that rises for any reason you need to know about it. Must admit if the frost free thing doesn't "know" it's doing a defrost cycle and can supress the alarm for the expected duration plus a bit it is poor design. Actually I'd also like a to low temp alarm as well. When we bung 3 loaves of bread in the freezer it alarms due to the temp rise. Put it into "rapid freeze" mode but then forget about it until I spot the display showing -31C... -- Cheers Dave. |
#4
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Freezer door alarm
Mike Barnes wrote:
I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? Its simple enough if you can do some electronics. A metal foil contact on each face, but not used as a swtich, rather used as a detecting capacitor. An oscillator uses those contacts as its frequency determining capacitor. Door closed, C higher, f higher. Output from osc goes thru cap and is threshold detected. You also need the circuit to detect correctly if the foils connect, so provide a dc path for that condition too. Now, with door open/closed reliably detected, its up to you to add whatever suppression you want, eg timer, cancel etc, and whatever output you want, eg LED while not closed, and beeper if not closed for 3 minutes or more. If you cant do electonics... youre stuffed. NT |
#5
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Freezer door alarm
In uk.d-i-y, Dave Liquorice wrote:
On Thu, 9 Apr 2009 09:38:36 +0100, Mike Barnes wrote: Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. Don't be such a lazy B and buy "frost free" heaps of ****e then. Well, we've got it now. And it's attached to the fridge that we rather like. And it's a non-standard cabinet size that just happens to suit our kitchen rather well. So we're in no hurry to swap it. The important thing *is* the temperature if that rises for any reason you need to know about it. Must admit if the frost free thing doesn't "know" it's doing a defrost cycle and can supress the alarm for the expected duration plus a bit it is poor design. Now there's a thought. I was about to counter that it's the temperature of the food that matters, whereas a short increase in air temperature (which is what the alarm is responding to) is of little consequence. It's an aftermarket alarm, which obviously doesn't know when the defrost cycle is. Answer: wrap the sensor in a little insulation (e.g. put it in a food container) to shield it from short-lived temperature rises. I'll get onto that straight away. Thanks! But an effective "door not closed properly" alarm would be much better. Actually I'd also like a to low temp alarm as well. When we bung 3 loaves of bread in the freezer it alarms due to the temp rise. Put it into "rapid freeze" mode but then forget about it until I spot the display showing -31C... Here's your answer... http://digitron.co.uk/line.aspx?lne_...2-f80b4ea44a08 -- Mike Barnes |
#6
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Freezer door alarm
In uk.d-i-y, Jim wrote:
wrote: I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? How about one of the window burglar alarms sensors that uses a magnet and reed switch? Excellent idea - and not too conspicuous if mounted *under* the door. I can't imagine why I didn't think of that, because I recently designed some very effective LED drawer lights using exactly what you suggest. I even know where to get the right sort of switches, with contacts that *close* when the magnet is withdrawn (the opposite of what's needed for alarm applications). It might be a bit of a fiddle getting the range right but it's a very promising idea. Thanks. -- Mike Barnes |
#7
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Freezer door alarm
In uk.d-i-y, wrote:
Mike Barnes wrote: I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? Its simple enough if you can do some electronics. A metal foil contact on each face, but not used as a swtich, rather used as a detecting capacitor. An oscillator uses those contacts as its frequency determining capacitor. Door closed, C higher, f higher. Output from osc goes thru cap and is threshold detected. You also need the circuit to detect correctly if the foils connect, so provide a dc path for that condition too. Now, with door open/closed reliably detected, its up to you to add whatever suppression you want, eg timer, cancel etc, and whatever output you want, eg LED while not closed, and beeper if not closed for 3 minutes or more. If you cant do electonics... youre stuffed. I can do the electronics at a pinch, but I was hoping for something simpler, that didn't involve running a wire to the door or a constant battery drain. Thanks for the thought. -- Mike Barnes |
#8
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Freezer door alarm
On Apr 9, 9:38*am, Mike Barnes wrote:
I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? -- Mike Barnes Its not a FIsher & Paykel one by any chance?!? Matt |
#9
Posted to uk.d-i-y
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Freezer door alarm
Mike Barnes wrote:
I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? Some years ago (prolly about 20), I made one for Mum's freezer. I got the innards out of a musical birthday card, a miniature microswitch and a small piece of wood (as an actuator for the microswitch). I glued the card innards and the microswitch on the side of the freezer and the wooden block on the edge of the door. OK, you had to listen to the tune incessantly whilst the door was open, but the problem (of leaving the door slightly ajar) went away. The battery in the card outlasted the freezer! Nowadays, of course, musical birthday cards are bases around digital samples, so they don't play annoying monophonic tunes that keep going indefinitely. |
#10
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Freezer door alarm
Mike Barnes wrote:
In uk.d-i-y, wrote: Mike Barnes wrote: I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? Its simple enough if you can do some electronics. A metal foil contact on each face, but not used as a swtich, rather used as a detecting capacitor. An oscillator uses those contacts as its frequency determining capacitor. Door closed, C higher, f higher. Output from osc goes thru cap and is threshold detected. You also need the circuit to detect correctly if the foils connect, so provide a dc path for that condition too. Now, with door open/closed reliably detected, its up to you to add whatever suppression you want, eg timer, cancel etc, and whatever output you want, eg LED while not closed, and beeper if not closed for 3 minutes or more. If you cant do electonics... youre stuffed. I can do the electronics at a pinch, but I was hoping for something simpler, that didn't involve running a wire to the door I think youre out of luck then. Sticking extraflex to the underneath edge of the door shouldnt be hard. or a constant battery drain. Thanks for the thought. why would one run it off a battery? If you want a simple switch in series with a beeper, you could do that but dont expect decent performance. NT |
#11
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Freezer door alarm
Mike Barnes wrote:
I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. I had one for a fridge which was a red plastic apple shape incorporating a light sensor. I don't know if the leakage around a freezer door slightly open would be enough for it to operate. Chris -- Chris J Dixon Nottingham UK Have dancing shoes, will ceilidh. |
#12
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Freezer door alarm
In uk.d-i-y, wrote:
On Apr 9, 9:38*am, Mike Barnes wrote: I've had several freezers with "door open" alarms but they've been all been f***ing useless. Door wide open when I'm rearranging stuff? Beep beep bloody beep, yes, thank you, but it's obvious the door's open isn't it? Door half an inch open because one of the drawers isn't quite pushed home? Silence. Thermometer-based alarms are useless because they routinely go off during the automatic defrost cycle. The problem with the makers' "door open" alarms are that they work on the hinge side so they're spectacularly inaccurate. What's needed, *obviously*, is a switch at the opening edge of the door. But it seems to be beyond the wit of the manufacturers to understand that or to put it into practice. end rant I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I wonder if some sort of magnetic detector might work better - there are, after all, magnets in the door seal. Or perhaps a low-profile keyboard-type switch between the cabinet edge and the seal? Or any other ideas? -- Mike Barnes Its not a FIsher & Paykel one by any chance?!? Give that man a cigar! But there's the same problem with our other freezer (Zanussi) and its predecessor (Philips). -- Mike Barnes |
#13
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Freezer door alarm
On Thu, 9 Apr 2009 11:37:23 +0100, Mike Barnes wrote:
Actually I'd also like a to low temp alarm as well. Here's your answer... http://digitron.co.uk/line.aspx?lne_...aef2-f80b4ea44 a08 Hum, two things to ponder. What is the range like with the transmitters inside an earthed metal box, I notice that they mainly stress having the display on the fridge/freezer. Also what batteries do they use for the unit in the freezer, most batteries don't like much below 0C let alone the -18C or more of a freezer. -- Cheers Dave. |
#14
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Freezer door alarm
On Thu, 9 Apr 2009 09:38:36 +0100 Mike Barnes wrote :
I did try making my own "door open" alarm many years ago, using a timer operated by a microswitch stuck on the side of the cabinet with a lever between the cabinet edge and the door seal. I can't remember why but it wasn't very successful, probably not robust enough for a kitchen environment. I bought a Candy fridge freezer a few years back and cursed it more than one because the magnetic seals weren't very and the freezer door would bounce slightly open if you didn't pay attention. The fix was easy but only realised it when I got my new fridge here. Just make sure that there is a slight rearward tilt thus making the door self closing. Not 100% re a drawer left open of course. -- Tony Bryer, 'Software to build on' from Greentram www.superbeam.co.uk www.superbeam.com www.greentram.com |
#16
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Freezer door alarm
In uk.d-i-y, Dave Liquorice wrote:
On Thu, 9 Apr 2009 11:37:23 +0100, Mike Barnes wrote: Actually I'd also like a to low temp alarm as well. Here's your answer... http://digitron.co.uk/line.aspx?lne_...aef2-f80b4ea44 a08 Hum, two things to ponder. Your scepticism does you credit. :-) What is the range like with the transmitters inside an earthed metal box, I notice that they mainly stress having the display on the fridge/freezer. Mine works through the front door of the freezer and then 2.5m across the kitchen to the side of the other freezer. I haven't experimented further. Also what batteries do they use for the unit in the freezer, most batteries don't like much below 0C let alone the -18C or more of a freezer. ISTR they recommend lithium. Not many places stock lithium AA so I ordered some from CPC. While waiting for those to arrive I put in some ordinary Duracell alkalines (both sensors). That was at least a year or two ago and I haven't needed the lithiums yet. -- Mike Barnes |
#17
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Freezer door alarm
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#18
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Freezer door alarm
In message , Chris J Dixon
writes Mike Barnes wrote: I had one for a fridge which was a red plastic apple shape incorporating a light sensor. I don't know if the leakage around a freezer door slightly open would be enough for it to operate. Or if it would work when the kitchen is in darkness. Chris -- Clint Sharp |
#19
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Freezer door alarm
Clint Sharp wrote:
In message , writes If you want a simple switch in series with a beeper, you could do that but dont expect decent performance. Hall effect sensor, PIC Micro waking on interrupt, programmable delay so it only complains after a preset period and a low battery monitor.. Tiny current consumption when in sleep, hall effect should work with the door strip and you can make the sensing range adjustable in software. Parts cost probably under a fiver too. Anyone interested? NT I doubt many people are set up for PICs. A single hex invertor chip would probably do the lot. NT |
#20
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Freezer door alarm
In article et,
"Dave Liquorice" writes: Actually I'd also like a to low temp alarm as well. When we bung 3 loaves of bread in the freezer it alarms due to the temp rise. Put it into "rapid freeze" mode but then forget about it until I spot the display showing -31C... Did that with my Hotpoint once. I don't know how low it went, but it was below -40C where the mercury (or red stuff) went off the scale as it all went into the thermometer bulb. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
#21
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Freezer door alarm
On Apr 10, 8:00*am, (Andrew Gabriel)
wrote: In article et, * * * * "Dave Liquorice" writes: Actually I'd also like a to low temp alarm as well. When we bung 3 loaves of bread in the freezer it alarms due to the temp rise. Put it into "rapid freeze" mode but then forget about it until I spot the display showing -31C... Did that with my Hotpoint once. I don't know how low it went, but it was below -40C where the mercury (or red stuff) went off the scale as it all went into the thermometer bulb. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] When we open our freezer the light comes on! Maybe tie something into that? Perhaps a bell-transformer that will send low voltage to a buzzer and/or light elsewhere. |
#22
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Freezer door alarm
On Thu, 9 Apr 2009 09:38:36 +0100, Mike Barnes
wrote: I've had several freezers with "door open" alarms but they've been all Or any other ideas? Ensure everyone knows how to shut the freezer door? -- http://www.freedeliveryuk.co.uk http://www.holidayunder100.co.uk |
#23
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Freezer door alarm
On Fri, 10 Apr 2009 10:43:59 -0700 (PDT), stan
wrote: When we open our freezer the light comes on! But when you close it are you really sure it goes out? -- |
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