Hi,
I am trying to find on the market a photoelectric smoke sensor for my project with Arduino, but I can't find one. I have only found projects using MQ-2 (which is not suitable due to high consumption).
Is there anyone aware of a good photoelectric smoke sensor on the market?
@jremington thank you! That's what I was looking for.
Reading the datasheet of MAX 30105 (thesmoke detector) , I am interested in setting up a battery-powered smoke alarm, with wifi capability (to send the alarm over internet).
The problem is that I can't power an ESP8266 through batteries, otherwise it will last few hours. My idea is to power the MAX30105 and find a way to have from it a trigger to power the ESP8266 and launch the message.
Do you know how to get this trigger from the chip, without having the i2c bus always working?
The MAX3010x is not by itself a smoke detector. It emits light at various wavelengths and measures the reflected light, so the host application needs some computing power to determine whether particles or features of interest are present.
See the Sparkfun "hookup guide" for some application examples.
The manufacturer refers interested parties to a vendor who will supply smoke detection algorithms for a fee.
For a battery powered smoke detector, you will need the entire system to be in deep sleep or powered down most of the time, waking up occasionally to make measurements.
Thanks, but I can’t keep a smoke detector in deep sleep. It could miss fire!
If it is device hacking and you mean the small commercial smoke detectors, usually powered by a 9volt battery, optical versions are very common here and with a long battery lifetime (> 2 years).
Every 30 seconds or so, they switch a led for few milliseconds and watch for scattered light (caused by the optical properties of smoke).
If the ESP8266 is mostly in sleep mode and is configured to wakes up (a) if there is an alarm or (b) once daily to deliver battery status etc. , you should get away without requiring mains power.
Here is one (not necessarily a recommendation) Battery Optical Smoke Alarm - Kidde 29HD
Please REREAD the last line of my post, all the way the end.
Thanks, that was my idea too. But in order to make a measure each 30 seconds, the MCU must be awake...
Yes sir, I got your message and re-read it. When you say “wake up occasionally” what interval do you mean for a smoke detector?
The wakeup and sample interval would be for you to decide.
For the required background on building battery powered gizmos, you need to read about sleep and wakeup mechanisms.
Most MCUs have an internal watchdog module that operates completely independently of anything else, and can be programmed to wake the MCU at regular intervals, even from power down sleep modes. Batteries last for years if this is done properly, but getting to that point requires significant effort.
If you use a smoke detector of the type I have indicated, the MCU does NOT have to wake at the smoke measurement frequency (say once every 30 seconds in the previous example). It depends how much of the existing electronics you retain but you'd best leave the detector part as it is and interface the MCU to the buzzer built into the alarm. That means the MCU waking only if there is an alarm condition.
Yes, I know. I have several devices using this technique, but it is not suitable for a smoke alarm, as you need to be warned as soon as possible.
No you don't! Then you get lots of false alarms and then no one will trust the alarm when there really is a fire.
Paul
Some types of smoke detector work on ionizing radiation ( e.g. Americium) and probably respond more quickly. Those can't be obtained in all countries.
Also, the internet may not be reliable for such critical application. For example, the fire may be caused by your router overheating.
Yes, but with these considerations I am afraid the solution is not easy.
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No mains (it is not reliable in case of fire)
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No internet/wifi (same reason)
The only solution seems to be a GSM device, but it can't be battery--operated.
Why is the mains power not reliable? It will be the first arriving fire fighters that control the mains power. My home has a mains power smoke detector with a 9 volt battery backup. Yours could be the same.
Paul
Because the first cause of fire here in Europe is electricity failure. And in case of a shortcircuit, mains will drop before the device could derect fire.
- Sent from my mobile phone. Sorry for typos -
You should probably check into more modern studies of fire in European homes.
These two surveys identify smoking, cooking, use of electrical appliances and candles as by far the most common causes of fire.
https://www.ifv.nl/kennisplein/Documents/09-06-24_rapport_consumer_fire_safety_pdf1.pdf
https://www.childsafetyeurope.org/publications/info/factsheets/fires-in-the-home.pdf
So, if anyone in your family smokes, cooks food or uses electrical appliances, a mains-powered smoke detector would be your first, best and safest choice.
I appreciate your support efforts, but I need to put the smoke alarm into a small room full of electrical appliances. So mains is not a option. That's it.
Power supply use a hammer. Get a 12V 20Ah LiFePo4 battery to supply the entire project. Step the 12V down to what ever.
I have a RPi powered by battery running 24/7.
I use a 12V LiFePo charger plugged into the wall, to charge the LiFePo4. The charger will up the voltage when its time to charge the battery and shut the charge off or just down to a trickle when charged.
The battery supplies a 5V regulator that powers the RPi.
At any moment the charger could be charging the battery, or not charging the battery but 24/7 the RPi has power.