$10 DIY Wifi Smoke Alarm Notifier (Roost & Nest Alternative) (Full Tutorial)

SimpleIOThings is the easiest and cheapest way to build DIY IoT projects with no coding or soldering required!

This tutorial will teach you how to build a Wifi Smoke Alarm Notifier for about $10 dollars. You won’t have to code anything, and you won’t have to solder or buy expensive electronics equipment. Any services you are asked to use will be 100% free. Its that easy. Lets get started!

There’s an old saying, If a tree falls in a forest and no one is around to hear it, does it make a sound? What about your home or office smoke alarm? If it goes off, but you’re away from home and no one hears it your house is toast. That definitely matters. While you might think this is unlikely to happen, the truth is that unattended cooking is the #1 cause of home fires.

However with the emergence of IoT devices, now there are some cool products on the market right now that will send you a smartphone notification when your smoke detector goes off.

Nest Smoke Alarm + Carbon Monoxide Monitor ($99, Nov 2015) – A replacement for the traditional smoke alarm that sends an alert to your phone when it detects smoke.

This looks like a great device, but for some consumers it will be too expensive. Especially if you need multiple devices, it starts to get very expensive very fast. What if I told you you could build yourself a simple sound sensor that sends you a smartphone notification, SMS, and even call your phone when your current smoke detector rings. You could also build this for about $10 bucks. If that sounds interesting to you, read on!

I know you’ve seen these types of tutorials on the internet before, and usually they say something like, just buy a breadboard, soldering iron, breakout board, serial adapter, etc. etc. and after you’ve spent about $50 dollars you can build a cheap Internet of Things (IoT) device. Well, sorry internet. We nerds sometimes forget that most people don’t really have these things lying around. That’s why I built this website around the idea that IoT devices can be built without coding knowledge, soldering, or complicated prototyping.

One of the reasons why IoT devices can be built so easily now is because of the ESP8266 development board. IoT enthusiasts have been excited about the ESP8266 because its a full system on a chip (SoC) that has onboard wifi connectivity that can cost as low as 3 dollars. The IoT community has been building with Raspberry Pi and Arduino microcomputers for a while now, and while capable these computers cost up to $35 dollars, don’t have onboard wifi, and aren’t easily powered with common ports like microusb. The standalone ESP8266 chip is great, but doesn’t have an easy to use power supply and it’s hard to configure without special cables.

To make building IoT devices both easy and cheap, I recommend using the ESP8266 development board. The ESP8266 development board is bigger and a little more expensive than standalone ESP8266 chips, but its easier to connect to a PC, upload custom software, and it can be powered with a common microusb cable.

ESP8266 standalone chip (right) and ESP8266 Development Board (left)

Also, the price of the board is less than $5 dollars! (~ $4.60 USD via AliExpress, Nov 2015) This means that many simple IOT devices can be built for 10 dollars or less. So without further ado, lets build a $10 Wifi Smoke Alarm Notifier!

(Note: I can already hear a thousand nerds out there groaning because I’m using the dev board instead of the standalone chip. Remember this page is about building IoT devices easily. This isn’t the cheapest possible way to make a device, but in my opinion its worth it to pay a couple extra dollars for the convenience of a microusb interface and power connection.)

STEP 1: Gather Your Materials

Its a good idea to buy your parts first because on the sites where the merchandise is cheapest (Ebay or Aliexpress) shipping times are rather lengthy. Depending on where you live in the world, it might take some time for your components to reach you so its better to do this sooner in the process than later. Here’s a list of things needed for this project. FYI, I’ve included some affiliate links to the cheaper places you could buy these components. I’ve done my best to ensure the ads display the lowest price goods that are relevant to this project, and if you buy through them you’ll be helping me maintain this site. Thanks! 😉

Required Components:

(FYI, if you’re just seeing text below with no images, its probably because you have an adblocker on. I know ads suck, but in this case they were actually a creative way to continuously update the page with the lowest cost parts. Prices change, so if I used static links and pics, the link would quickly become outdated. Please consider turning off adblock for this site for the best experience.)

– General Components

ESP8266 Development Board (~$3 @ AliExpress; Nov 2017)
AliExpress.com ESP8266 Development Board

DIY Project Box Enclosure 100x60x25mm

Female to Female Jumper Wires

MicroUSB cable (10′ Cable Recommended)

USB Wall Charger

Project Specific Parts

Microphone Sensor (Get the red one with the small screw)

Suggested Tools:

These are tools needed to build the IoT device in this tutorial, but aren’t necessarily required.

Pliers

Hacksaw

Smoke Detector

Precision Screwdriver Set

Great. Now like I said, its gonna take a while for your stuff to get to you, so in the meantime lets setup some digital infrastructure that your new device will use.

STEP 2: Setup Your IFTTT Account & Recipes

The Wifi Smoke Alarm Notifier, and all of the projects on SimpleIOThings use an internet service called If This Then That (IFTTT). IFTTT executes an action, like sending an SMS or posting a Tweet, when an event takes place. Combinations of events and actions are called recipes, and you can do a lot of cool stuff with IFTTT recipes. For example, I use publically available recipes to automatically tweet my Facebook posts, change my phone wallpaper to the NASA Picture of the Day every morning and send me a smartphone notification if its going to rain tomorrow. Click here to setup an IFTTT account. You’ll need it later to execute actions from your IoT devices.

Using the Maker Channel

For SimpleIOThings projects we’re going to use IFTTT recipes that use the Maker Channel. The Maker Channel allows people to create recipes that interact with DIY devices. The DIY devices you can build using tutorials from SimpleIOThings will send messages over the internet to the IFTTT Maker Channel, which then triggers actions like phone calls and SMS messages. The Maker Channel can also send messages to DIY devices to trigger actions on the device as well.

Follow the link and connect to the IFTTT Maker Channel.

Once you connect to the Maker Channel, take note of your “Maker Key,” which is an alphanumeric code that identifies you and your DIY devices when they send web messages. You can jot it down somewhere, or you can always go back to https://ifttt.com/maker to find it.

Using IFTTT Recipes & Organizing Events and Actions

Now that you’re connected to the Maker Channel, lets build some recipes that will trigger cool actions like smartphone notifications, SMS notifications, and phone calls. A greatfeature in IFTTT is the ability to share recipes. I’ve shared my recipe here, but just take a look before you sign up for it.

IFTTT Maker & SimpleIOThings Smartphone Notification Recipe

There are also other cool recipes that you can use. Using IFTTT, your devices can trigger phone calls, emails, and send SMS’s to your friends. Here are links to some more recipe I’ve shared for your convenience.

You can sign up for each recipe using the links. All you need to do is input an event name like “SmokeAlarm” and clicking “Add.”

The reason why I asked you not to sign up for the IFTTT recipes just yet is because I want you to think about how you want to organize your event triggers and recipes. Lets take a look at them in the next section.

Organizing Recipes

Understanding how to organize your IFTTT Maker recipes will help you trigger the desired actions for a given event.

Example 1: Smart Button – Triggering One Action

One of the devices you can build on SimpleIOThings is the Wifi Smart Button. In the default case, I’ve assumed the user is going to use it to report a bad event (like security problems in a store) but it can really be used to send just about any message.

Lets say in this example you are using it to tell you’re significant other that you’re thinking about them. In a case like this, maybe you want to just send your significant other a quick SMS that says “Thinking of you. 😉 ~[Your Name].” You COULD send your partner an SMS, PLUS an email, and a phone call at the press of a button, but that would probably be overkill (depends on the message you’re trying to send I guess). To keep it classy, you could setup an event called “SmartButtonThinkingOfYou” in IFTTT, and have it trigger ONLY the smartphone notification with a sweet message. Later, once your program your smart button to trigger the “SmartButtonThinkingOfYou” event over Wifi, the following process should occur:

You press the button.
The Smart Button sends a message (via HTTPS protocol for you nerds out there ;] ) to IFTTT over Wifi with your Maker Channel Key and the Event Name (SmartButtonThinkingOfYou).
IFTTT receives the message, finds your recipe, and sends a SMS to your partner’s phone carrier.
Your partner receives an SMS, and smiles.

Example 2: Wifi Smoke Alarm Notifier – Triggering Multiple Actions

Pretty awesome right? However, there’s another project (Wifi Smoke Alarm Notifier) on SimpleIOThings that notifies you when your smoke detector goes off. When this device sends a message to IFTTT, you’d probably want an SMS, Smartphone Notification, Email, and Phone Call to tell you something might be wrong at your house. So for the Smoke Alarm Notifier, you’d probably want to setup an event called “SmokeAlarm” and sign it up for all 4 of those recipes. To do this, you’ll have to sign up for the SMS, Smartphone Notification, Email, and Phone Call recipes with the “SmokeAlarm” event, and then later program your Wifi Smoke Alarm Notifier device to send the “SmokeAlarm” event name when its triggered. Once that’s done, when your device triggers it should result in the following process.

Smoke Detector goes off.
Wifi Smoke Alarm Notifier detects the noise from the Smoke Detector alarm.
The Smoke Alarm Notifier sends a message to IFTTT over Wifi with your Maker Channel Key and the Event Name (SmokeAlarm).
IFTTT receives the message, finds your recipe, and then:
- Sends a Smartphone Notification
- Sends a SMS.
- Calls your phone with an automated message.
- Emails you.

The bottom line is, you can setup your devices to tell IFTTT that an event occured, and depending on how you’ve configured your IFTTT recipes, the event can trigger a single action, or multiple actions. Some good planning and organization ahead of time will help you trigger the desired actions when an event occurs.

In the case of this particular device, I would recommend utilizing multiple recipes all triggered by an event (named, for example, SmokeAlarm). A smoke alarm going off is an event you want to respond to with some urgency so you probably want to be notified by any means possible.

Testing Recipes

Once you’ve signed up for your recipes you can test your them by going to the Maker Channel, then clicking “How to Trigger Events.” In the following page, enter the event name you created earlier, and click “Test It.” You should get a smartphone notification.

Download the IF App for Android & IOS

To receive smartphone notifications and monitor your IFTTT activity, you can download the IFTTT app on your smartphone. The app can also be used to manage your recipes and channels. You can download the “IF” app from the Android Play Store, or the Apple Itunes Store.

IF App Download Links

Okay! We’ve got some really nifty digital infrastructure setup for your project. Soooooo…its gonna take a while before you get all this stuff…so its probably best to bookmark this page and come back after it’s all arrived. See you in a few weeks!

STEP 3: Install Firmware to your Dev Board

Oh hi there! Welcome back. I know its been a while. Maybe the seasons changed in your part of the world. Governments may have risen, switched hands, entered alliances, broken alliances, fallen, and then risen again. Yea…it takes a while to get your stuff. But now that it’s here, lets start building!

Now we’re going to teach the dev board to understand a language. Right now its just a mashup of metal and silicon, but after this step it will understand how to execute commands in a powerful software language called “Lua” (which is in the Python family of computer languages for you nerds out there). Don’t worry though, you won’t be expected to code anything.

You should connect your dev board to your computer’s USB port using your cable like so. If you have windows computer and an internet connection, the drivers for the board should automatically load. If for some reason it doesn’t you can Google “NodeMCU drivers” and a number of websites with appropriate files should show up.

Once your drivers are installed, you’ll also need to determine which communications port the device is connected to. Click your “Start” button and type “Device Manager.” Your device manager should pop up. Click and expand the “Ports (Com & LPT)” menu and you should see your device listed there. In my case, my ESP8266 dev board’s port was set to COM18. For now just take note of that and jot it down somewhere.

Now we have to install “firmware” on to the dev board. This firmware will allow the board to execute programs and understand Lua. To do this we need to download a “flashing” program and the firmware itself. The flashing program will use the firmware file to load firmware onto your board.

The latest versions of the flashing program can be found on github, a popular and trusted site for computer programmers to collaborate on projects. Pick the appropriate flasher based on whether your PC is using a 32-bit or 64-bit operating system.

– 32-bit ESP8266 Flasher
– 64-bit ESP8266 Flasher

The firmware file can be found on Github. Follow the link below. As of 1/3/2018, the file version that works best is at the bottom of the release page. It is the “integer” version and it will look something like this: [nodemcu_integer_0.X.X-dev_201XXXXX.bin]. A screenshot is also provided below for reference.

NodeMCU Firmware Releases for ESP8266 Development Board

There are also some other interesting places to get firmware for the ESP8266 dev board, including a custom firmware builder, however a number of users have reported trouble with the firmware they get from other sources. For now, I recommend sticking with the Github release.

Okay, if you’ve made it this far, you’ve connected your dev board to your PC, obtained the port number, installed your dev board drivers, and downloaded the ESP8266flasher program and the firmware .bin file. Awesome.

Now find your downloaded ESP8266 flasher program and start it. This should pop up:

Change the port number to the port for your ESP8266 Development Board, which you jotted down earlier.

Now click the Config tab, and click the topmost gear on the right hand side.

Once you click the gear icon, use the dialog box to find your firmware (.bin) file in your downloads folder and click “Open.” Then go back to the “Operation” Tab and click “FLASH!” Once the progress bar moves all the way from left to right, your dev board can now understand the Lua language. Congrats!

The last task in this step is to download a program called LuaLoader and use it to connect with your dev board. LuaLoader is a program that can understand the Lua programs your board is running. It also has a lot of handy tools that let you setup wifi, read digital outputs, and so on. Once again, Github has what we need.
– LuaLoader @ Github

Once you’ve downloaded LuaLoader, extract the zip file (if needed), open Lualoader.exe as an administrator. To open as an administrator, right click Lualoader.exe, and then click “Run as an Administrator.” Once open, click Settings, Com Port Settings, and set the port to the one your dev board is connected to and click “OK.”

Then click “Connect” in the menu bar of the Lualoader program. Your ESP8266 dev board should flash an LED for a second, and your Lualoader will show you some strange characters. Congrats, you now have a dev board that is ready to receive a program.

STEP 4: Install Sensor Specific Software to your Dev Board

Great! Now your dev board speaks Lua. Its ready to start communicating with the world. Lucky for you, I’ve already written the software necessary to get your device up and running. Just visit our Downloads page and download SimpleIOThings.zip.

Unpack the .zip file, and then find it. Open “SensorSetup.bat” and it will open a Command Terminal Window. It might look scary, but you only have to input some simple text in response to some questions.

Go through the prompts. Ignore the parts about flashing your dev board (we already did that) and enter your IFTTT Maker Key, the Maker Event name, the sensor’s location info, etc. It will also ask you how many sensor inputs you’d like before an event is triggered. Depending on your use case, you may want to set your threshold lower or higher. When you’ve completed the setup questions, the terminal window will edit your software files (.lua files), and then automatically close.

Now go into your Lualoader and click “Upload File…” on the right side menu. Find your unpacked folder and click on any .lua file and click “Open.” Your first .lua program file will upload into the dev board. Now that you’ve set the right directory, click the dropdown menu and click “< Upload all .lua files.” Now ALL of your .lua program files will upload into your dev board.

One last thing. Before we hit restart, setup your wifi network name and password. To do that, enter the wifi network name and password for the network the device will use and click “Set AP.”

Now click “Restart!” If everything went well, you should see “Listening for Sensor Inputs…”

Awesome. That means your ESP8266 dev board is connected to your wifi network and fully programmed. Now we’ll move onto the last step, which is to construct the device.

STEP 5: Build the Smoke Alarm Notifier

All the way back in step 1, we talked about gathering materials. Hopefully now you have everything in hand and your board is programmed. Go ahead and get all your materials together in one space.

Go ahead and unplug your dev board (there is almost no electrical danger to you from touching the dev board while plugged in, but might as well err on the side of safety).

Connecting the Wires

Now, grab the microphone sensor and three female jumper wires. Plug the jumper wires into the “D0,” “GND,” and “+” pins of the sensor. It should look like this.

Now grab your dev board, and observe the names of the pins on the board. Go ahead and plug your jumper wires into the “GND”, “3V3”, and “D2” pins on the right hand side, making sure that “GND” connects to “GND”, “+” connects to “3V3”, and “D0” connects to “D2.” It should look like this:

Believe it or not, you’ve just constructed an Internet-of-Things device! The rest of this tutorial is just some calibration and making the device look good.

Just a quick note for those of you who are interested in the electronics. When setup this way the microphone is powered through the GND and 3V3 pins (via a complete circuit). When the sound around the sensor exceeds a certain level (as determined by the potentiometer, described in the next section), the sensor sends a signal via the “D0” pin to the dev board’s “D2” pin. The ESP8266 dev board registers a change in electrical signal which the chip detects as a sensor input. Pretty cool!

Calibrating Your Microphone Sensor (First Time)

Now that the cables are all connected, go ahead and power your dev board with a microusb cable and place the sensor near your smoke alarm. If everything was connected properly, at least one light should be illuminated on your sound sensor. You’ll notice that the sensor has a small screw on it. Turning this screw calibrates something known as the “potentiometer.” In simpler terms, this screw determines what level of sound will trigger a signal through the “D0” pin from the sensor to the dev board. If you turn the screw clockwise, a lower level of noise (quieter) will cause the sensor to send a signal to the ESP8266 Development Board. If you turn the screw counter-clockwise, louder noises are required to trigger a signal to the development board. You can also visually confirm when your sensor is sending a digital signal to the dev board because a second LED light will illuminate on the board. Use the 2nd LED and the screw to set the potentiometer to a level where normal ambient noise and conversation will not trigger a signal to the dev board (i.e. 2nd LED does not light up).

Now go ahead and test your smoke alarm (most smoke alarms feature a “test” button which will trigger a limited number of alarms. (Note: The alarm will be loud. If you’re sensitive to noise, it might be a good idea to wear hearing protection). The 2nd LED should light up when the alarm is ringing. Now turn the screw counter-clockwise until the 2nd LED does not light up when the alarm is ringing. Once you get there, stop, then turn the screw clockwise until the 2nd LED is just lighting up again. Stop turning the screw and keep this configuration until later. Modifying Your Enclosure Okay, now lets move onto the enclosure. Actually, the enclosure is nice to have, but not 100% necessary. You could put this project inside of a soap case or a pencil box, or other common household objects. Just make sure the case is not flammable, and isn’t conductive (i.e. not metal). At about a dollar though, I think its nice to have a professional looking enclosure, so I think its worth buying one. The enclosure needs a place for wires to come out of the back, and for sound to enter through the front. I sawed a piece of the back of the enclosure out, and used pliers to tear off some of the enclosure so sound could enter through the front. Here’s some pictures of how I modded my enclosure.

There are other ways to do this, such as using a soldering iron to melt holes into the plastic. How you choose to house your electronics and modify your enclosures is up to you. The way I did it with a saw is kind of “hacky” (pun intended) but worked for me. Alright, now you can put your electronics into the enclosure. Plug your usb cable into the dev board, and make sure your jumper wires are well positioned, but don’t close the project box just yet. Calibrating Your Microphone Sensor (Second Time) Now that your sensor is inside the enclosure, you will need to set your microphone sensor to be triggered by lower sound levels (since the enclosure will dampen some of the Smoke Alarm noise). Turn the screw by a half clockwise turn, then close the project box. Orient it towards the smoke alarm similar to how it will be oriented when finally installed, then and test the alarm. If its possible, try to observe if the 2nd LED is triggered. If that’s not possible, connect the device to your PC, and use LuaLoader’s readout. By now, the software you’ve uploaded should be working and displaying “sensor input counted” if the smoke alarm is triggering a signal. If its not sending a signal to the dev board, turn the screw clockwise by another half turn, close the project box, and read again. Repeat this process until the smoke alarm triggers a signal while inside the enclosure.

Step 6: Final Installation

The last thing you’ll want to make sure is that the Wifi Smoke Alarm Notifier works once its installed on a wall or ceiling near your Smoke Alarm. I used some push pins to make sure both the enclosure and the cord are secure, and look neat. Of course, I tested it again once it was up on the wall, and it’s been there ever since, vigilantly waiting 24/7 for an alarm to sound.

And we’re done!

Your Wifi Smoke Alarm Notifier is now up and running. Give it a test run and it should trigger whatever you’ve set it up to do, whether that’s a smartphone notification, SMS, phone call, email, etc.

I hope you enjoyed building a super simple Internet-of-Things device. Hopefully you will be able to use it for something useful, or use it to do something fun. If you enjoyed this tutorial, consider donating at the link below. Thanks for reading!