How do I calibrate soil or hydroponic sensors?

Calibration makes a sensor’s readings correct. You put the probe in a known condition (dry air, water, a buffer solution…) and record what it reads, so the board knows how to turn the raw reading into a true value.

Before you start

• Role needed: Admin or Owner to change. A Viewer can only see the values.
• Where it is available: web.
• The Calibration button shows only on soil and hydroponics device cards.
• Get ready: dry air and a cup of water for the soil probes, pH 7.00 and 4.00 buffer solutions for the pH probe, and a trusted TDS meter to compare with.

How to get there

1. Sign in (see How do I sign in to my farm?).
2. Press Devices in the side menu. On a phone, it is in the bar at the bottom of the screen.
3. In “📡 Devices”, find the soil or hydroponic device card and press Calibration under it.

Steps

1. Press Calibration. A window opens with the values you calibrate.
2. Press Show live raw readings. The board sends its raw readings for a few minutes, and Reading now appears beside each value.
3. Put the probe in the condition the row asks for, and wait until the reading settles.
4. Press Record current reading and the reading moves into the field. Or type the value yourself.
5. Repeat for the other rows, then press Save.

What do I calibrate?

Board	Rows
Soil	For each soil sensor: the probe in dry air, then in water
Hydroponics	pH probe in the 7.00 then the 4.00 buffer (volts), the TDS correction factor, and the distance to the water with the tank empty then full (cm)

For the TDS factor, type what a trusted TDS meter reads in the same water, then press Record.

After saving

You see “Saved. The Master sends it to the board within a minute or two.” Follow the status at the top of the window:

• ⏳ Waiting for the board to confirm: the board has not received the change yet.
• ✓ On the board: the board confirmed the calibration.
• The board has not reported its calibration yet: it does once it runs the latest firmware.

Badges and going back to default

• default: the board uses the program’s original value. set: you entered a value.
• Back to default clears your value; then press Save.
• Each row shows On the board (what the board holds), Reading now and the accepted range. A value outside the range is refused.

Tips

• Wait for the reading to settle before recording; recording too early gives a wrong calibration.
• After calibrating soil, check Readings on Home.
• You do not need to stay on the page after saving.

Common problems

There is no Record button. No raw readings have arrived. Press “Show live raw readings” and wait.

“Waiting for the board” stays for long. The Master node carries the change. Check that it is connected (see Device states).

I do not see the Calibration button. The device is neither soil nor hydroponic. Change its role from its card.