Knowing full well I didn't have a mains wired chime to meet the spec in the blink doorbell camera, I bought one anyone as I liked the idea.
What I do have at home is a very simple Byron battery operated doorbell - a pushbutton switch, doorbell wiring to the two terminals on the chime unit and 2xC or D batteries which make the bell "ring" in a buzzer style (i.e high frequency hitting a bell until the bell push button is released).
When I got the Blink doorbell I experimented with wiring the two contacts on the Blink doorbell to the Byron chime; I assumed that as all the Blink was doing was opening / closing a circuit that this would be sufficient to make my bell chime.
Unfortunately it is not working. I can test with a multimeter than pressing the blink chime does indeed open the circuit, but "something" means that this doesn't cause the doorbell to ring. Given that simply bringing the two doorbell wires together does cause the ring, there's something else going on, but my knowledge of electronics is insufficient to help me out.
I *think* it is something like the blink camera's terminals not going sufficiently "dead" for the PCB in the Byron chime to reset, so when the circuit is re-opened it can't start the ringing process.
If that is the case, I was thinking that there must be a simple in-line component that I could put in place which would "cleanly" open and close the circuit based on what the Blink cameras terminals do.
Is this a likely feasible way forward, and / or what could I do to test what is really "happening"?
I have a doorbell with 2 D-cells. I recently had a problem where the bell would only give one weak ping when the button was pressed. I found that the current when I shorted the wires was about 2A initially, but the bell push had got corroded and was too resistive to pass that much. My solution was to solder gold contacts into the bell push, which should now withstand damp weather.
The Blink doorbell seems to send a radio signal and switch its camera on when the button is pressed. It's powered by internal batteries so won't work and could be damaged if you feed it 3V from your Byron batteries. It's contacts are only good for a few mA and unlikely to work your bell.
The sounder plays a recording so you can't work your Byron bell by some connection to the Bling sounder. I very much doubt they go to the expense of putting a mechanical relay in there which could be used to ring your Byron bell.
I don't like these smart bells because they trigger the same long sound no matter how the button is pressed, so you have no idea how desperate the caller is!
's expecting a bell transformer providing:
16 - 24 volts AC at 50 - 60Hz, and 40VA maximum. (that's US, normally UK doorbells are 8v or 12v AC. Not sure if they have adjusted the product or they just assume we're all like them)
Your batteries are giving 3V DC. I suspect that means it can't tell when the bell push is 'released', as there is never enough voltage on the line. It's looking for 16V across the terminals to indicate the circuit is open (button not pushed) and it never sees that.
It's hard to have both a thing that expects 16v AC and a bell that can only cope with 3V DC before burning out. You could put 16v AC across the bell push and then step that down and rectify it to 3V DC, but it would be simpler to get a bell transformer and a 16-24V chime.
It's possible it'll cope with a higher DC voltage, like a pair of 9V batteries giving 18V, and maybe that will be correctly detected. But you'd then need a chime capable of running from 18V DC. You could regulate the
18V down to 3V but the batteries wouldn't last long.
I would probably be looking at hard wiring here and changing the chime. You can get plug-in bell transformers which would mean you'd only need to go as far as a socket, not back to the fusebox.
Theo, thanks. I must admit the electronics is beyond me!
As I posted, I know what I've got is out of spec, but I'm pretty sure that what is in the camera is a simple relay that opens and closes a circuit so surely that can mimic the pushing of a button?
I'll post a video of the various outputs that I can see via a multimeter when a button is pressed and perhaps that can help find a way.
A battery chime is the only available option for me in the location available, certainly without making a big ol' mess in an area with limited neat cabling opportunities and not much access to power!
Just to clarify, some of the smart doorbells are wired in a setup with the existing bell push, transformer and existing chime. The push and chime work as normal, but the smart doorbell feeds off the line to take power and detects if the bell has been pushed (ie the line power goes away). That's the kind of setup I was thinking of.
If the chime is just an actuator, ie you remove your old button and instead there's a button on the smart bell that you push, and it's just intended to close a relay contact to mimic the button but without any powering or voltage detection stuff, then it's possible it'll work with your 3V setup. But it may be it's trying to be clever and thinks there's a fault because it can't see enough voltage on the line.
Does the app/etc give you any feedback about problems?
"With a Sync Module or compatible wiring, your battery life extends to 2 years, and you can start Live View or take thumbnails in the Blink app.
Without a wired connection or a Sync Module, you enter Event Response mode where you only receive motion alert and doorbell press notifications, and you must tap a notification within 60 seconds to enter Live View with two-way talk. [This implies camera is running continuously, on battery?] "
And there is some subscription thing that eventually might enter the picture.
"Choose to save and share clips in the cloud with a free trial of the Blink Subscription Plan,
or locally with the Sync Module 2 and USB drive (each sold separately).
Trial valid until January 2023. You will be notified at least 30 days before your free trial expires with information on how to subscribe. "
Sometimes it is better to find a review of the item first, and see if it is for you or not.
OK, this is getting a bit closer. I still can't figure out why this mentions a 900MHz radio. When device to device appears to be 2.4GHz.
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Sync Module 2 Specifications
Wi-Fi Internet Always-on broadband connection [High upload speed requirement] Upload Speed 2 MB per second (minimum) [Cloud storage, review, preview] Power 5 volt 1 Amp DC Operating temperature 0° to 35° C Designed for indoor use Frequency Range 2.4 Ghz Wi-Fi ~900 Mhz Blink Low Frequency Radio [what is this for ???] Signal Strength Using the Blink app Sync Module Settings screen, you should have "three bars" of connectivity. You can move the Sync Module and Wi-Fi router to find the best balance of signal strengths.
USB Storage File format H.264 .mp4 USB port Type A USB Drive size 1 GB to 256 GB (with at least 375MB free) Drive format ExFAT (preferred) FAT32, FAT (MS-DOS)
The video doorbell spec is next.
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Power Main: Two, size AA 1.5 volt Lithium non-rechargeable batteries Chime Wiring: 16-24 volts AC, 50 60 Hz, max 40 volt/amps
Note: Batteries are always required for use.
Battery Life Two years of regular use <cough>
Camera Sensor 1080p HD Color, 15 to 30 fps Field of view: 135 degree horizontal and 80 degree vertical Night Vision 1080p HD Black & White 850 nm infrared LED light Motion Sensor Type: Frame to frame image comparison Downward tilt: 10 degree Field of view: 150 degree horizontal Max range: 23 ft (7m) when mounted 48" (122cm) above ground Effective range: 12 ft (3.6m) when knee level motion is detected
Wi-Fi (such as broadband, fiber, or DSL). Wifi network: 2.4 GHz 802.11b/g/n. Network Speed Download Speed: Broadband recommended Required Upload Speed: 2 MB per second or more
Audio Speaker output and 2-way audio recording LED light ring (around the ringer button) Red LED - Not connected / Ready Green LED - Connection activity Blue LED - Button Press Weather Resistant Rated IP-54 Weatherproof Operating Temperature -20° to 45° C Size 5.1" x 1.7" x 1" (130 x 42 x 27 mm) Weight 3.2 ounces (91 grams) Mobile App Blink Home Monitor Operating Systems iOS, Android, Fire OS Compatibility Sync Module 2, Sync Module, Alexa enabled Fire and Echo devices Mounting holes 3/32" (2.27mm) diameter drill bit for just the screw 7/32" (5.3mm) diameter drill bit for the wall anchor
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Device internal photos (Blink Video Doorbell):
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The gold dots could have something to do with the speaker. The J connector could be how power gets from the batteries to the main PCB.
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Summary:
1) Never derives power from any external source. A "transformer source" like a bell system, would not help.
2) Does appear to work stand alone. Using 2.4GHz radio. Somehow.
3) When near Sync Device, likely reduces amplitude of 2.4GHz radio signal. This saves a bit of power.
4) Chime contactor via a semiconductor. No relay is visible for chime function. Semiconductor needs a certain amplitude signal to work ??? Camera appears to be able to measure chime wire amplitude in software and knows sufficient signal is not present.
5) If Echo View, tiny cube camera, or Alexa are present, these devices can make a chime sound inside the house. Each of those devices has a speaker.
6) Sync device has no speaker. It cannot make a chime. But would have been a natural fit for such a function.
7) FCC photos don't show the module that touches the gold dots. The gold dots seem to be isolated from adjacent ground plane. I think I see an RF connector on the end of the gold "L". The rubber gasket could be related to damping the speaker module.
8) The more I look at the photos, the more mysteries I spot. It's like a freaking cellphone.
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"Use Mini as an indoor plug-in chime for Blink Video Doorbell. Hear a real-time alert from Mini when someone presses your Video Doorbell."
Still potential spyware though.
"See, hear, and speak to people and pets in your home from your smartphone with Blink Mini’s live view and two-way audio."
"With a Sync Module or compatible wiring, your battery life extends to 2 years, and you can start Live View or take thumbnails in the Blink app.
Without a wired connection or a Sync Module, you enter Event Response mode where you only receive motion alert and doorbell press notifications, and you must tap a notification within 60 seconds to enter Live View with two-way talk. [This implies camera is running continuously, on battery?] "
And there is some subscription thing that eventually might enter the picture.
"Choose to save and share clips in the cloud with a free trial of the Blink Subscription Plan,
or locally with the Sync Module 2 and USB drive (each sold separately).
Trial valid until January 2023. You will be notified at least 30 days before your free trial expires with information on how to subscribe. "
Sometimes it is better to find a review of the item first, and see if it is for you or not.
OK, this is getting a bit closer. I still can't figure out why this mentions a 900MHz radio. When device to device appears to be 2.4GHz.
formatting link
Sync Module 2 Specifications
Wi-Fi Internet Always-on broadband connection [High upload speed requirement] Upload Speed 2 MB per second (minimum) [Cloud storage, review, preview] Power 5 volt 1 Amp DC Operating temperature 0° to 35° C Designed for indoor use Frequency Range 2.4 Ghz Wi-Fi ~900 Mhz Blink Low Frequency Radio [what is this for ???] Signal Strength Using the Blink app Sync Module Settings screen, you should have "three bars" of connectivity. You can move the Sync Module and Wi-Fi router to find the best balance of signal strengths.
USB Storage File format H.264 .mp4 USB port Type A USB Drive size 1 GB to 256 GB (with at least 375MB free) Drive format ExFAT (preferred) FAT32, FAT (MS-DOS)
The video doorbell spec is next.
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Power Main: Two, size AA 1.5 volt Lithium non-rechargeable batteries Chime Wiring: 16-24 volts AC, 50 60 Hz, max 40 volt/amps
Note: Batteries are always required for use.
Battery Life Two years of regular use <cough>
Camera Sensor 1080p HD Color, 15 to 30 fps Field of view: 135 degree horizontal and 80 degree vertical Night Vision 1080p HD Black & White 850 nm infrared LED light Motion Sensor Type: Frame to frame image comparison Downward tilt: 10 degree Field of view: 150 degree horizontal Max range: 23 ft (7m) when mounted 48" (122cm) above ground Effective range: 12 ft (3.6m) when knee level motion is detected
Wi-Fi (such as broadband, fiber, or DSL). Wifi network: 2.4 GHz 802.11b/g/n. Network Speed Download Speed: Broadband recommended Required Upload Speed: 2 MB per second or more
Audio Speaker output and 2-way audio recording LED light ring (around the ringer button) Red LED - Not connected / Ready Green LED - Connection activity Blue LED - Button Press Weather Resistant Rated IP-54 Weatherproof Operating Temperature -20° to 45° C Size 5.1" x 1.7" x 1" (130 x 42 x 27 mm) Weight 3.2 ounces (91 grams) Mobile App Blink Home Monitor Operating Systems iOS, Android, Fire OS Compatibility Sync Module 2, Sync Module, Alexa enabled Fire and Echo devices Mounting holes 3/32" (2.27mm) diameter drill bit for just the screw 7/32" (5.3mm) diameter drill bit for the wall anchor
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Device internal photos (Blink Video Doorbell):
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The gold dots could have something to do with the speaker. The J connector could be how power gets from the batteries to the main PCB.
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Summary:
1) Never derives power from any external source. A "transformer source" like a bell system, would not help.
2) Does appear to work stand alone. Using 2.4GHz radio. Somehow.
3) When near Sync Device, likely reduces amplitude of 2.4GHz radio signal. This saves a bit of power.
4) Chime contactor via a semiconductor. No relay is visible for chime function. Semiconductor needs a certain amplitude signal to work ??? Camera appears to be able to measure chime wire amplitude in software and knows sufficient signal is not present.
5) If Echo View, tiny cube camera, or Alexa are present, these devices can make a chime sound inside the house. Each of those devices has a speaker.
6) Sync device has no speaker. It cannot make a chime. But would have been a natural fit for such a function.
7) FCC photos don't show the module that touches the gold dots. The gold dots seem to be isolated from adjacent ground plane. I think I see an RF connector on the end of the gold "L". The rubber gasket could be related to damping the speaker module.
8) The more I look at the photos, the more mysteries I spot. It's like a freaking cellphone.
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"Use Mini as an indoor plug-in chime for Blink Video Doorbell. Hear a real-time alert from Mini when someone presses your Video Doorbell."
Still potential spyware though.
"See, hear, and speak to people and pets in your home from your smartphone with Blink Mini’s live view and two-way audio."
Yep, I'm aware of all that. As I think I posted I was aware from the outset that I'm trying to work something "out of spec".
However, there are users who have got their simple battery powered bell pushes working fine.
In fact, if I simply attached a simple light bulb circuit (in the style of a school circuit board) I could demonstrate that that the Blink camera would cause the bulb to illuminate and shut down under the controls in the device.
So the Blink in practice does do what I want it to do, but just not with the specific battery operated chime that I've got.
I'm asking a more nuanced question.
Assuming I have two terminals on a device which demonstrate either an "open" or "closed" position via a multimeter, how might put something "electronic" in the way that mimicked that opening and closing and on the "other side" of the circuit opened / closed a new switch.
Actually, its kind of like, if I were going there, I'd not start from here. Can you not just fit a motion activated camera and a normal bell push as before? The problem with a lot of wireless door intercoms seem to be that one cannot open the system from inside, only when the bell has been pushed to call the remote unit, so I'm rethinking my system as the outside unit makes a noiseeven when the remote is out of range, so some tie in to a mobile phone would seem to be the way to go, perhaps via bluetooth, which seems to have more range than the intercom. Brian
We know the load on the other side, is AC and involves a current of maybe 500mA or 1 ampere.
A triac can close an AC path.
You need to drive the gate, to make it work. The only reason I searched for a diac article, is to show the gate control needs both polarities. For power switching applications (rather than building a dimmer), triacs can use a zero-crossing chip to develop a gate signal (no idea, never done it).
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You can also use a relay to do it. The relay will need a power source on the coil side, in series with the Video Doorbell interface, to trigger the relay and make a fake doorbell switching event. In addition, the coil driving would need a snubber, but the Video Doorbell should already be expecting a transient when it drives the bell circuit itself.
An optoisolator is an electronic way of isolating two circuits from one another. But it is a DC device, and adds nothing to this exercise. Optos don't have a lot of power switching capability, for the basic chip. Maybe you could drive the coil on a reed relay with one, but that's a stretch. You can rectify an AC signal from a source, to drive the LED inside the optoisolator, so there are ways to convert AC stimulus, to isolated DC response.
I don't know of a black box that will solve this with "zero fuss".
You might try adding additional resistance at the load end, to give the video doorbell something to "work into". In the same way we sometimes have to put an incandescent into the same luminaire with a LED bulb, just so a digital light switch can work :-) Some digital wall mount light switches, need the 60W incandescent load, for the switch to work properly. Note that a 60W light bulb, draws 120W when it is cold. When warmed up, it draws 60W. Whereas power resistors (the white ceramic ones), the resistance is more constant. You can use light bulbs if you don't have a drawer full of power resistors, but there is that annoying "cold" behavior to consider.
Since i don't know what your doorbell load looks like electrically, the resistor idea is purest supposition on my part. Maybe the doorbell is already giving
*plenty* of load, for all I know.
You would likely need lower voltage bulbs, like four bicycle 6V bulbs in series as a 24V load.
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The "duration" setting in the Video Doorbell software, must be adjusted to give a functional doorbell response.
Make sure you've read these and tested, before going on some sort of electronics hacker adventure.
The mechanical chime setting causes the circuit (between the two screw connetors) to open for a brief period only, presumably allowing the "ding" on a two tone chime with the "dong" then being the hammer returning to it's normal place.
The digital chime allows the circuit to stay open for a duration of time and this is what I expect to be needed for my "buzzer style" doorbell chime.
Although in electronics terms I am pretty "dumb", I'm smart and competent when it comes to apps and that sort of stuff so take it as read that I've explored all of the software / device specific options.
I am pretty astounded that the electronics bit sounds as complex as your post suggests!
What could I measure at either the doorbell end or the chime end that would help answer the questions? I've got a basic multimeter...
You'll need two circuits. The is a DIN rail kit 24VAC transformer for a Blink. Ring has a DIN rail kit, but it is DC. Verifying the transformer output is 24V, is a first step before wiring the Blink to it. If you know your mains to be exceptionally high, select a 16VAC transformer instead. It will then run at 19VAC or 23VAC or whatever. The Blink will then be happy, as the voltage is between 16 and 24 volts. (I did not see ANYTHING in the Blink that looked like a power converter.)
24VAC <=== be aware your mains actual voltage, xfmr turns ratio, affect voltage! | 50 ohm 25W (runs at 12W) | Blink()
Blink() | 24VAC_Return
In your first test, you will not be using the chime. You will attempt to use motion detection or the recording function, and characterize
*actual power consumption*.
The Blink Video Doorbell always uses the 2x1.5V Li cells for power.
But some portion of the circuit, has the option of sucking power from the 24VAC source. I still have not been able to get any idea what the sucked power level is (1 watt?, 5 watts?).
Blink is Immedia Semiconductor, a company whose claim to fame was a four core processor chip running at 200MHz. The low frequency, makes it possible for even a dopey bastard to make a processor. You can do 200MHz processors in an FPGA for example, and do that as a prototyping step before making custom silicon.
But the Blink Video Doorbell has more to it than that. It does seem to list a 900 MHz radio function that runs at 1/5th the transmit power of the 2.4GHz Wifi. The Blink products are geofenced, in the sense that the UK Blink will follow UK standards for the 2.4GHz band plan for Wifi (one channel different than US and so on). Since there is no evidence the
900MHz is used for anything, we will assume it never runs. You may need a UK geo Sync 2 as well for it.
it could be that the Wifi module in the Blink, is using power from the chime circuit.
Using your multimeter, check for voltage across the
50 ohm resistor. This will tell you whether current is being drawn when the Blink is motion sensing with its PIR sensor. It may also choose to run the camera at a low rate, and do a delta between frames to detect moving objects. One owner claims it would false positive on something fluttering in the field of view.
So first you would start by configuring the unit with "chime OFF" as you don't want a huge slug of current flowing down the resistor when attempting to detect a small small voltage across the 50 ohm resistor. With "chime OFF", now enable motion sensing, walk around in front of the camera, so you can note any power draw from the thing. The rich feature set is only available, when the 24VAC is present on the terminals.
You do this setup on your lab bench, not on the front door installation.
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The second test, is to set the meter on 200VAC full scale, so you can measure 24VAC across the 50 ohm resistor. Set Chime to ON, then press the button, and see if the Blink shorts the two terminals and causes the full 24VAC to appear across the 50 ohm resistor.
All that this does, is prove the Blink can run a US chime. It can probably sink 1.6 amps. The 50 ohm resistor should not be a particular challenge for it.
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For your next test, you can use your multimeter to record the DC voltage on the real chime circuit, not the lab setup shown above. With the above setup, you do that at the comfort of your lab bench.
Knowing the DC voltage of the chime circuit, you can attempt a circuit like this. Once you've measured the chime voltage, you can go back to your lab bench and set this up.
8VDC <=== emulation of what your UK chime presents | 50 ohm 25W | Blink()
Blink() | 8VDC_return
With Chime set to ON, and in digital chime mode, the unit should only respond in Event Mode. It will take a press of the Blink button, for the Blink to wake up and close the contacts, and make the 8VDC supply appear across the 50 ohm resistor. The power level in the resistor in this case, is less. (The power rating on the resistor, was so we could do the 24VAC test. This test won't make the 50 ohm resistor as warm.)
Since the Blink is not supposed to run supervisory functions off an 8VDC supply, before you press the button, no current at all should flow through the 50ohm resistor. There should be zero volts DC across the resistor, before you press the button. Walking in front of the unit, setting off the PIR, should not happen.
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You can test with a lower voltage.
5VDC <=== Assumes a digital chime with TTL voltage control | 50 ohm 25W | Blink()
Blink() | 8VDC_return
But at some point, the SSR in the circuit, is not going to be able to switch that one ON. You can push the button, and eventually, get no current flow through the resistor, whether Blink button is pushed or not. Blink is not supposed to suck power for supervisory functions, when the voltage is this low. Even though it is possible to make very wide range SMPS to suck power from just about anything.
I still have not been able to find any circuit characterization whatsoever. That's why you're doing these tests.
I think you're missing a crucial part; the "event mode only" bit only applies in the absence of a Sync Module (which I have).
The simplistic understanding I have on that is that the Sync Module handles "live" connectivity to the camera via a low power radio signal instead of using Wifi, the logic being that Wifi is a higher power draw and would run out the 1.5v battery pretty swiftly.
As I've got the Sync Module, my camera doesn't operate in Event Mode only, I can browse it "live" if I want to etc. There is no additional functionality I'm missing out on vs when it is wired to a transformer.
My understanding of the wiring to a transformer bit isn't that it powers anything in the camera / doorbell, it is more that it describes the max current / power (whatever the right term is!) that the components are built to withstand.
This reddit thread (which you can see I've posted) engages with someone who appears to know some of this stuff - but we ran out of steam.
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