This simple home-made product can be repeated by anyone who is able to connect three wires. With this thing, you can remotely control the temperature, for example, in the country.
The thermometer requires Wi-Fi.
The temperature can be viewed on the website and in the mobile application of the People's Monitoring service narodmon.ru. There are also temperature graphs for the year and you can set temperature limits, when you go beyond which the service will warn you with push messages, SMS and letters to the mail.
To assemble the thermometer, you need a NodeMCU-CH340 microcontroller for $ 2.65 and digital temperature sensor DS18B20 for $ 1.41. If desired, you can add another digital indicator TM1637 for $ 0.77. You will also need a 4.7K resistor, wires, any charging from a phone with a MicroUSB connector. It is convenient to use an electrical junction box as a housing.
Most likely, you can use the very tiny Wemos D1 Mini controller, but I have not tried it.
In the basic version, it is enough to solder the temperature sensor to the controller (red wire to 3V, black to GND, yellow to D4), a resistor is placed between the yellow and red wires of the sensor (in the photo the sensor is soldered to D1, do not pay attention).
This is optional, but you can connect a shield. The thermometer supports four types of screens (color TFT 240x320 dots, OLED 128x64 dots, two- or four-line LCD, seven-segment LED). In my opinion, it is best to install the cheapest four-symbol indicator. The indicator has four pins, we connect them to the controller (VCC to 3V, GND to G, DIO to TX, CLK to RX).
I tried to connect an OLED screen to the thermometer, but the numbers on it are tiny and a lot of unnecessary information is displayed, including the non-disconnectable address of the firmware developer's website.
This thermometer can be connected to the People's Monitoring and made public if its sensor is located on the street. If the thermometer is located indoors (for example, in the same dacha), the service allows you to use it as a non-public one. This is how data from two such thermometers is displayed on the site (note that only one thermometer can be connected to the service for free).
And so in the application (of course, the sensors can be renamed).
The application sends push messages if the thermometer stops transmitting readings, or starts transmitting after a long break.
As you probably already guessed, in order to turn the controller into a cloud thermometer, you need to download the firmware and configure it. But this is much easier to do than many of you thought. :)
Firmware can be created using the service wifi-iot.comand load with NodeMCU Flasherbut I'll make it easy for you: here in this archive two files - flasher and ready-made firmware. Just connect the controller to the computer, start the flasher, select the led.bin file (Config-gear), specify the virtual COM port to which the controller is connected, and press "Flash".
When the firmware has been uploaded, disconnect the controller and reconnect it (you can use a computer, you can use any charger). Press the Reset button three times with a pause of at least half a second. The controller will create a temporary Wi-Fi hotspot called WiFi-IoT without a password. Connect to this point with your smartphone, and click "connect to the network". The thermometer setup web page opens.
You can configure everything at once, you can only configure the Wi-Fi connection and continue the configuration on the computer. I'll show you how to set up everything at once on your phone:
1. Click "Hardware", check the "Enable DS18B20" checkbox and change its GPIO to "2". Click "Set". Click "Main".
2. We go to "1-Wire", there is "Clear & Scan List". The sensor address should appear. "Main" again.
3. If you connected the screen, go to "7SEGM", put the "Enable" checkbox, enter 3 in the "GPIO Clk" field, in "GPIO Data" 1. Click the top "Set". Change item "1" to DS18B20 1, press the lower "Set". Click "Main".
4. Go to "Servers", put the checkbox "Enable Narodmon.ru" there, press "set". We write down the ID of the thermometer. Click "Main".
5. We see in the main menu that the temperature has appeared.
6. Click "Main". In the "AP name" field, enter the name of the home Wi-Fi access point (only Wi-Fi 2.4 Ghz is supported), in the "AP Pass" field, enter the password for Wi-Fi. We press the third button Set, which is immediately under the entered password.
Disconnect the controller from the power supply and turn it on again. It will now connect to home Wi-Fi. You can go to its web interface from the browser at the address that can be viewed in the web interface of the home router or using reconnecting to the temporary access point of the controller: again three times click on the RST controller, reconnect to it with the phone, go to "Main" and see below address. In this case 192.168.1.212.
We register at the People's Monitoring: https://narodmon.ru/?invite=ammo1 (referral link, but it doesn't give me money, but the ability to connect more sensors and store data longer).
The thermometer sends data every 5 minutes, so if 5 minutes have not passed since the setting, you need to wait a little or manually enter the sensor web interface and send the data in the section "Servers".
On the People's Monitoring, go to "Profile - My sensors".
Click "Add" and enter the ID of our thermometer (we saved it in step 4).
If my explanation seemed difficult to you, right here there is a very detailed step by step instructions.
In fact, everything is very simple and this homemade product can really be made and configured in ten minutes. As for the prices, it certainly cannot fail to impress how cheap it all is.
© 2020, Alexey Nadezhin
For ten years I have been writing every day about technology, discounts, places of interest and events. Read my blog on the site ammo1.ru, in LJ, Zen, Mirtesen.
My projects:
Lamptest.ru. I test LED lamps and help figure out which ones are good and which are not so good.
Elerus.ru. I collect information about domestic electronic devices for personal use and share it.
You can contact me in Telegram @ ammo1 and by mail [email protected].