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Before every path

Sensor and credentials

Every device sends to a sensor in HydroNode, and every request proves that it comes from that sensor. Create the sensor once, then pick up what your path needs: a Sensor ID and Secret, a webhook token, or nothing at all.

01Create a sensor

Your first sensor

In HydroNode a sensor is the identity of your device. HydroNode accepts no data for a sensor that does not exist. An account holds up to 20 sensors, free.

  1. 1
    Start on the Dashboard
    Press Create sensor in the head of the device list.
  2. 2
    Name it and pick the environment
    Give it a name such as Growbox A. Choose Indoor for rooms, grow boxes and greenhouses, Outdoor for anything outside. The environment decides what counts as normal, and only outdoor sensors can become a station on the map.
  3. 3
    Keep the credentials
    After Create sensor HydroNode shows the Sensor ID and the Secret. You find both again any time, see below.
The Create new Sensor form with the name Growbox A, Indoor and Outdoor, and 3 of 20 sensors usedThe Create new Sensor form with the name Growbox A, Indoor and Outdoor, and 3 of 20 sensors used
A name and an environment. On the right you see how many of your 20 sensors are used.

Using the Device Builder? It creates the sensor for you if you like and writes the credentials onto the board itself. You can skip the rest of this page.

02Your path

What each path needs

PathNeedsWhere you find it
Device BuilderNothing to copyThe builder writes the credentials onto the board.
Arduino librarySensor ID and SecretSettings, Connection. Into the sketch.
LoRaWANWebhook token and DevEUIToken in your profile, DevEUI on the device. No Secret.
ESPHomeSensor ID and SecretSettings, Connection. Into secrets.yaml.
SDK (Python, Node.js, Go)Sensor ID and SecretSettings, Connection. Into your program.
Home AssistantAPI tokenProfile, API Tokens. Reads, it does not send.
03Sensor ID and Secret

Copy them from the settings

  1. 1
    Open the sensor
    On the Dashboard, click the sensor's name in the device list.
  2. 2
    Open its settings
    Press Settings at the top right, then Connection on the left.
  3. 3
    Copy both
    Under Direct connection you find the Sensor ID and the Secret, each with a copy button.
Connection settings of a sensor with the Sensor ID, a hidden Secret and Replace secretConnection settings of a sensor with the Sensor ID, a hidden Secret and Replace secret
Settings, Connection: Sensor ID and Secret for the direct connection.

The Sensor ID names the sensor and is not secret. The Secret signs every request (HMAC-SHA256), so HydroNode knows the reading really comes from your device and was not changed on the way. It never travels over the network itself.

04Keep it safe

If the Secret leaks

  • Keep the Secret on the device. Never publish it and never commit it to a repository.
  • In ESPHome put it in secrets.yaml, in Python or Node.js read it from an environment variable, in a sketch keep it in a header file that is not in Git.
  • Someone else might know it? Press Replace secret under Settings, Connection. The old one stops working at once, so the device stops sending until it gets the new one.
NextChoose your integration method