Just moved into a house that had a 'chime' doorbell, with power fed from its own MCB in the CU and through a transformer with 8V output, thereby presenting 8V to the chime to make it work.
I never find chimes to be loud enough when listening at a high volume to Led Zeppelin, AC/DC et al, so I bought one of these Byron things with a real 'Brrrrrriiiinnnggg' sound:
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I didn't realise that it works from two D-type batteries (1.5V each = 3V) so I've now got a 3V bell that has 8V presented to it from the transformer when the bell push is operated.
I don't know if that's going to do any permanent damage or not but the reason for posting is that, when the push is first operated the bell rings like a good 'un. If I press the push for two minutes the bell rings for two minutes. *However* once the bell push is released and pressed again, nothing happens - the bell does not ring at all! If I go back, say, half an hour later the bell once again rings as it should.
This is a repeatable pattern so what's wrong and how can I fix it - preferably without having to use batteries?
"The bell is powered through an integrated circuit which pulses the current to work the bell."
If you want a bell to run on the transformer try a Friedland D792 or D902 underdone bell or even a Friedland 56-012 Masterbell which is 12Vac but will probably run on 8v.
It's a DC bell that expects nothing more than a switch closure on the two terminals.
It does not want to have connections to any 8VAC circuits. The 8VAC stuff would need to be disconnected first. Then the isolated switch and its two wires, connected to the DCBell.
Summary: To stay within budget, just place the DCBell in the drawer and forget about it. I'm not being mean when I say that. That's the "voice of over-budget experience" speaking. By the time you're finished fixing this, you'll need a bank loan :-) Most people would want the existing chime and the DCBell to work in parallel, but as near as I can tell, this is a naive DCBell that is not designed to "play nice" with an existing AC bell. Nothing in the instructions addresses such details.
Could you design a circuit, to interface both bells ? Yes, you could. But if I drew the diagram, the material cost of becoming a hobbyist (brand new soldering iron, wire, protoboard...) and the obscurity of some of the items (just the relay would likely cost more than your DCBell), means only Bill Gates would do it this way.
And the usage of Wireless DoorBell products, there are still batteries or other non-ideal details. (The unlicensed spectrum used for door bells can be flooded with jammer-energy, which might cause a wireless door bell to operate continuously. for example, all the garage doors in town here were disabled for two days once, by an illegal transmitter in an embassy.) Wireless is a solution, but it's not as reliable as running water or dialtone.
I think it's more geeks in general (rather than just the Yanks) who invent these meaningless contractions. As for your doorbell, perhaps it overheats and then needs to cool off.
You can extract energy from the existing doorbell transformer.
But then, when picking up switch closure information (in parallel with the existing door bell circuit), you might need an optoisolator or other scheme (a relay, where the coil is across the existing chime).
Means an order to Farnell, a new soldering iron and other stuff.
This shows how a person is planning to connect two different chime systems, so they don't get in one anothers road. The relay provides isolation, so they don't see each others voltages or operating principles. Picking a signal off the existing chime to run a relay coil, you might even be able to use a reed relay for the job.
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And that means the two chimes are "wired in series", in the sense that the right-most chime sounds a millisecond before the left one. As it takes a short time for the relay to close. They don't sound at absolutely the same instant in time. Some circuits you can draw up, there can be a significant delay between one circuit firing and the next circuit firing.
With the relay in place, then you can power both chime circuits from the same transformer. And make 3VDC from the 8VAC source on a continuous basis (for as long as mains are running).
( Example of a linear regulator, after the diode rectifier solution )
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Since the DCBell using some sort of Lithium cells, I'd want to check exactly what voltage those produce, before picking a regulator from the catalog.
Just for the hell of it, a fancy one, energy extractor. The LM317 is a programmable regulator, voltage set by resistor ratio. The band gap reference inside the LM317, determines the lowest voltage it can regulate to. An LM317 can go as low as 1.25 VDC on output. So making it do 3V in the example, isn't tough for it. The LM317 would only get warm, if the DCBell is an energy pig, when running.
You're driving a DC logic level input, with an AC signal well outside the operating range of the logic chip.
The reason the thing survived, is the genius who designed this thing, probably put a resistor in series to prevent it from smoking. With no resistor, it should have permanent blown up, within milliseconds of being connected to the existing circuit. You're very lucky it still works.
And I expect the genius designer, did consider that people would wire it to inappropriate levels, currents and voltages. Maybe the genius even figured out, that by making it take time to recover, the user would realize they'd done something naughty.
3V is rather a low voltage for making audio effects. Only a saturating logic could drive a speaker hard enough, to alert you. And it's probably just a little 555 circuit (NE555 or LM555). If an audio amplifier chip was in there, it would need a higher rail voltage to give good output.
Depends on the make. The first wireless doorbell I fitted was a Byron, and the receiver *ate* AAs - if I got 3 months I was lucky. I replaced it with a Honeywell/Friedland; the AAs in that last at least 2 years.
One thing that concerns me, is this could be "just a battery and an old fashioned ringer". Interrupter style.
At this point, to determine if that was the case, I'd take my multimeter, configured for amperes of current, and put the scale on 10 amps, then connect the red and black lead to the two switch screwheads, and see if a measurable current flows when the bell rings. That might indicate an old style electromagnet pulling on a hammer.
There has to be a reason this device has a "preference" for a Lithium cell type. Do those cells have an internal BMS ? To protect against overload ? I don't think it is a rechargeable type, but if Lithium is involved, you'd think there would be potential for trouble.
Ive been l,looking into battery life for a project I am doing.
The secret is not in using less battery when active, it is in using less battery when INACTIVE.
And unfortunately wireless comms eat power. In my case the answer is to make it 'wake up' every few minutes and send a burst of data over the wifi. Sadly that's not an option for a doorbell
I think that’s just a ploy to sell lithium batteries. When we moved into our present house it had this same simple ringer. Powered by two orange HP11 batteries. Remember them? They must have been donkeys years old and last a good few years more.
Lithium batteries seems overkill when conventional batteries will last many years already.
Size vs capacity vs life expectancy at average current consumption? Your HP11 were somewhat large compared to a AA or AAA battery which is more common today.
My wireless doorbell takes 4 off D size alkaline batteries (HP11 equivalent) which can cost £7/8 for the set* which is comparable in cost to something like Energiser Ultimate Lithium AAs.
*For a battery that is going to remain in service for many years I prefer to fit something from a more respected manufacturer rather than a pound shop special. However, I have found Duracell AA and AAA batteries to leak like a sieve in recent years.
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