IOTA tutorial 30: Send DHT11 data to the tangle using ESP-01S, MQTT and MAM @Mobilefish

Uploaded August 2018 | Updated September 2026, 2 weeks ago

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This is part 30 of the IOTA tutorial.

In this video series different topics will be explained which will help you to understand IOTA.
It is recommended to watch each video sequentially as I may refer to certain IOTA topics explained earlier.

In this video I will demonstrate how to send DHT11 sensor data from an ESP-01S WiFi module to the tangle using MQTT and Masked Authenticated Messaging.

A complete step-by-step guide how to send DHT11 sensor data from an ESP-01S WiFi module to the tangle using MQTT and Masked Authenticated Messaging can be found at:
mobilefish.com/developer/iota/iota_quickguide_esp01s_mam.html

The source code used in the guide can be found at:
github.com/robertlie/dht11-esp01s

ESP-01S (ESP8266) WiFi module specifications:
- Flash memory: 1 MByte
- Max transmission distance: approx. 400 m (direct line of sight)
- Package size: 24.7mm x 14.4mm
- WiFi protocols: 802.11 b/g/n
- Supply voltage: 3.0 to 3.6V
- Operating current (average value): 80 mA
- Comes pre-programmed with an AT command set firmware.
- Operating temperature: -20 deg C to 85 deg C
- Not breadboard friendly
- Number of pins: 8
- Number of GPIO ports: 2 (GPIO0 and GPIO2)
- Not shielded
- One led (blue), will flash when data is transmitted

USB to TTL converter
To upload an Arduino sketch or firmware to the ESP-01S module an USB to TTL Serial converter is needed.
They are also known as USB-TTL converters, USB FTDI converters or FTDI adapters.
FTDI (Future Technology Devices International) is a company who produces the most well-known USB-Serial converter chips.
The USB-TTL converter, converts USB data signals to and from TTL-level serial data.
Serial data is transmitted one bit at a time at a specified data rate (i.e. 9600bps, 115200bps, etc.).
This method of serial communication is sometimes referred to as TTL serial (Transistor-Transistor Logic).
Serial communication at a TTL level will always remain between the limits of 0V and Vcc, which is often 5V or 3.3V.
A logic high ('1') is represented by Vcc, while a logic low ('0') is 0V.

MQTT
MQTT stands for Message Queuing Telemetry Transport and is a publish/subscribe event-driven messaging protocol for constrained Internet of Things devices and low-bandwidth, high-latency or unreliable networks.
MQTT enables messages to be pushed to clients.
The MQTT broker is the central point and is in charge of dispatching all messages between the senders and the rightful receivers.
Each client that publishes a message to the broker, includes a topic into the message.
Each client that wants to receive messages, subscribes to a certain topic and the broker delivers all messages with the matching topic to the client.
The client who publish the data and the client who receives the data don’t have to know each other, they only communicate over the topic.
This architecture enables highly scalable solutions without dependencies between the data producers and the data consumers.
TCP/IP port 1883 is reserved for use with MQTT.
TCP/IP port 8883 is reserved, for use with MQTT over SSL.

Check out all my other IOTA tutorial videos:
youtube.com/playlist?list=PLmL13yqb6OxdIf6CQMHf7hUcDZBbxHyza

Subscribe to my YouTube channel:
youtube.com/channel/UCG5_CT_KjexxjbgNE4lVGkg?sub_confirmation=1

The presentation used in this video tutorial can be found at:
mobilefish.com/developer/iota/iota_quickguide_tutorial.html

#mobilefish #howto #iota

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$LoRa/LoRaWAN tutorial 24: ABP Demonstration With The Things Network If you like this video and want to support me, go this page for my donation Paypal or crypto addresses: https://www.youtube.com/c/mobilefish/about This is part 24 of the LoRa/LoRaWAN tutorial. In this video series different topics will be explained which will help you to understand LoRa/LoRaWAN. It is recommended to watch each video sequentially as I may refer to certain LoRa/LoRaWAN topics explained earlier. In this tutorial I will demonstrate the Activation-By-Personalisation method. I assume you have watched Tutorial 22 and based on what I have done in Tutorial 22, I will continue where I left off in that video. Make sure a LoRa gateway is your area and your LoRa end device can send messages to that gateway. In Tutorial 21 I have explained the difference between Over-The-Air-Activation (OTAA) and Activation-By-Personalisation (ABP). On TTN, select application: youtube_demo_app On TTN, register a device: Device ID: youtube_demo_device2 Device EUI: 603252361D4B9C66 (Enter a random value consisting of 8 bytes) You can use this tool to create the device EUI: https://www.mobilefish.com/services/guid/guid.php In the Device Overview screen, select Settings (Top right corner) Change Activation Method to ABP. The Device Address (hex value), Network Session Key (msb, 16 bytes array) and App Session Key (msb, 16 bytes array) needs to be copied to our new Arduino sketch which I will explain in a moment. In the Arduino IDE, select menu File | Examples | MCC LoRaWAN LMIC library and select the ttn-abp sketch. Re-save the ttn-abp sketch and call it ttn-abp-mydemo. In this sketch you must enter: - The Network Session Key (NwkSKey). Enter as a 16 bytes array in big-endian format. - The Application Session Key (AppSKey). Enter as a 16 bytes array in big-endian format. - The Device Address (DevAdr). Enter as a 4 bytes hex value. Do not forget to add the prefix 0x. Same as in Tutorial 22, the message Hello, world!” is transmitted every 60 seconds. If we use this transmit time interval we will NOT comply with the TTN Fair Access Policy if we run this sketch for more than 24 hours and the data rate is SF7BW125 or even worse SF12BW125. Please do the calculations your self. Make the same pin mapping changes as explained in Tutorial 22. // Pin mapping const lmic_pinmap lmic_pins = { .nss = 10, .rxtx = LMIC_UNUSED_PIN, .rst = 5, .dio = {2, 3, LMIC_UNUSED_PIN}, }; Modify the loop function: void loop() { os_runloop_once(); } Connect the self build LoRa development board to your computer using the USB cable. In the Arduino IDE, select menu Tools | Board and select: Arduino/Genuino Uno In the Arduino IDE, select menu Tools | Port and select: your_port Compile ttn-abp-mydemo sketch. You should not see any errors. Upload the ttn-abp-mydemo sketch to the Arduino Uno. You should not see any errors. In the Arduino IDE, select menu Tools | Serial Monitor Select baud rate: 115200 Goto The Things Network console: - Select the app: youtube_demo_app - Select the registered device: youtube_demo_device2 - Select reset frame counters. Do this each time your end device is powered up. In the Device Overview screen, top right corner, select Data. The message “Hello, world!” (in hex: 48 65 6c 6c 6f 2c 20 77 6f 72 6c 64 21) is received by a gateway and send to the network server and displayed in the The Things Network console. Please note: There is no Join-Request message send. Check out all my other LoRa/LoRaWAN tutorial videos: https://www.youtube.com/playlist?list=PLmL13yqb6OxdeOi97EvI8QeO8o-PqeQ0g Subscribe to my YouTube channel: https://www.youtube.com/channel/UCG5_CT_KjexxjbgNE4lVGkg?sub_confirmation=1 The presentation used in this video tutorial can be found at: https://www.mobilefish.com/developer/lorawan/lorawan_quickguide_tutorial.html #mobilefish #lora #lorawan$