How to make a periodic buzzer/beeper from AC ?

Thread Starter

Externet

Joined Nov 29, 2005
1,419
An elderly person needs some periodic warning when the oven/burners of the electric range is on/left on, to prevent mishappenings.

In the simplest form; what would you do to emit a short (0.5 second) 'beep' or 'buzz' or 'ding' once a minute to warn the stove is on ?
Yes, 555s... Try something else, with minimalist clever components/design, perhaps activated by the AC power from the dash indicator neon warning bulbs, without the power supply transforming - rectification - regulation - timing stages.

Thought of a not very simple solution with a 1 rpm geared motor like microwave turntables use, hitting a bell every turn. A non so-mechanical option could be better.

Or... is there already an applicable gadget in the market doing that ?
 

wayneh

Joined Sep 9, 2010
16,124
Another approach might be an auto-off control system, which would be a nice feature in any range. You could forget the warning and just turn off the burners every 15 minutes or whatever. Maybe require entering a turn-off time in order to turn on a burner, just like you do now with a microwave.

I assume you're looking for an add-on solution? How are you planning to power this device, and how will it know the heat is still on? You could use a thermoelectric generator (reverse peltier) to power an alarm, and there are many possible solutions.
 

Thread Starter

Externet

Joined Nov 29, 2005
1,419
Thanks wayneh. Yes, an add-on feature. An auto-off could get me a roller pin on my head if cooking/baking is not done. Replacing the burner switches with microwave style mechanical timers would defeat the temperature control.
Power can be from the AC that the neon indicator get when any burner is on.
 

MaxHeadRoom

Joined Jul 18, 2013
19,387
One possible avenue to persue that may work is find a means of monitoring the current in both L1 L2, generally when an element is on, it is going to be 240v fed, the other aux things like timer clock etc are fed off of L1 (or L2) and N.
This would then monitor/include all elements on the stove.
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
19,387
One other simple way if they want something to constantly remind them is to remember to set the timer for 1 or 2 min upon using any element.
On mine, ( electronic timer) once the timer has timed out, it gives 3 beeps once every minute until reset.
The down side is it is not automatic and the timer has to be set.
Max.
 

wayneh

Joined Sep 9, 2010
16,124
I almost wonder if an IR detector mounted like a smoke detector, up above the stove, could be the better solution. No user action required. It does nothing most of the time, but chimes every 10 minutes when it "sees" heat below.

It might just become background noise and get ignored if the user cooks a lot and hears the chime too often.
 
1. sonalert modules. Goggle them and you can hear the various sounds

2. For the most part, about 15 minutes works most of the time unless your making soup or something. Turning on/off might be used to reset the timing interval.

3. Mom and I use a timer like this one: http://www.thermoworks.com/Extra-Big-Loud which we set when boiling water for ice tea or putting on a kettle for tea.

We used to have a mechanical timer that would never stop buzzing, but it's never been fixed. The thermoworks timer does have a volume control which accidently can be hit and the battery contacts aren't the greatest, but otherwise it works great. Initially it's a continuous alarm, then it sleeps for a while and beeps again. It also counts up when the count is reached.

Caveot: You have to get in the habit to hit stop twice. Stop 1x stops the current count, stop 2x clears the count.
So, for those doing 10 min cookie batches, there are less keystrokes.

So, for us, the timer works pretty well.

==

I actually have a really tough one. We have a vintage oven with NO gas off controls. The oven does not have a pilot. gas on, means GAS ON. It must be lit with a match. Since the stove is downstairs, it has been left on overnight once. The gas has been on too without being lit. There isn't a Natural gas detector down there either and the one upstairs probably needs to be replaced because it's too old.

It can be custom converted to a pilot. Self install. Definately not cheap. The customization involves taking pics and then the parts would be fabricated.

The same for water alarms. It an area I need to re-evaluate.

I also want to make sort of a "door prop alarm for a freezer. A freezer alarm was useless because you can;t hear it and it eventually resorts to a LED. When your not near the freezer, it doesn't help.

So, all or many, of the alarms have the "distance factor". A water alarm sitting on the window sill alarms, but if no one is around, you can't hear it. I had a wireless french drain alarm, but the indicator is in the bedroom.

For the freezer, I am planning something super simple. Opening the door will turn on a light that normally has to be on anyway. So, for now, have a child latch that at least tells me it's closed initially, If something falls, it can open the door about 3/8" of an inch.

A nice latch type of switch has been selected. It can be bought with various amounts of force like 10 lbs. I just haven't fabricated the brackets to mount it. Plan to mount with double-stick tape.

Alarms don;t help you when your away. Water gets in the property and your away because someone is in the emergency room in a hospital. You discover 4 days later. that the basement carpet is wet.

There's a PERS medical alarm on the property too. Again, local is upstairs.

A phone SMS would be nice, but I don;t always carry it.

In one unusual application at home, I decided to extend the bell of a cordless telephone set which has been expanded to the maximum of 4 handsets. If I'm outside doing work I usually have my cell, but when I'm doing laundry, I can hear the external land line ring, but not the paging function on the cordless phones.
I put, but have not properly installed a "baby monitor" to monitor the ring of the cordless phone in another room.
I can now tell the difference between a page and an outside line call.

With alarms, there's lots of issues to worry about. I did install a car alarm the wrong way and did professionally install a Hydride(toxic) gas/Hydrogen and other alarm shutdown system which worked at least once during an explosion. The explosion caused some re-design including installing the Hydrogen alarm that was sitting in a box, It was a Hydrogen explosion.

Big changes were to have dedicated purge cylinders in the same gas cabinet, elimination of all of the failed excess-flow valves and replace with orifices, Move from a non UL listed 120 VAC operated 3000 lb rated valve to a air operated valve. Piping that was designed for vacuum upgraded to handle cylinder pressure. In a normal situation, the lines would have only seen vacuum. They are used to pump out the regulator when changing cylinders. All exhaust gas velocity alarms replaced and upgraded. procedural changes, so cylinder changes occurred before normal work hours with SCBA.

My "shutdown" system was all simple relays and designed in the 80's. SO much about SIS (Safety Instrumented Systems) and PLC's. A very similar SIS alarm system was implemented for another added process which used a PLC and a UPS system, but it had to interface to my gas control.
 
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