Mopeka tank sensor

The Mopeka Tank type reads Mopeka Pro Check ultrasonic tank sensors — the pucks that stick magnetically to the bottom of a propane bottle (water variants exist too). The card shows the fill percentage and the raw measured liquid depth in millimetres. Read-only; the sensor broadcasts, so it never uses a Bluetooth connection and the Mopeka phone app keeps working alongside.

Adding one

Mopeka sensors are recognised automatically — add from Discovered nearby, or manually by MAC. No key needed.

Calibration — required for a meaningful percentage

The sensor measures the height of liquid above it; the percentage is computed from the calibration in the device's configuration:

• Full distance (mm) — the liquid depth when the tank is full. Default 400 mm; set it to the reading shown when your tank is actually full.
• Empty distance (mm) — the depth when empty, normally 0.
• Tank capacity (L) — your tank's size.

Until you set the full distance for your specific tank, the percentage is only approximate. The Distance figure on the card is the raw reading — use it: fill the tank, note the distance, enter it as Full distance.

Erratic or jumping readings

Ultrasonic sensors need good contact and a straight echo path. If the level jumps around: check the puck is centred on the bottom of the tank with its sync ring seated, use the sensor grease/mount Mopeka supplies, and expect readings to get less reliable when the tank is nearly empty — that's inherent to the measurement.

Problems?

• No readings at all → the sensor broadcasts rarely to save battery; give it a minute. Check the sensor's battery (it's a coin cell — the Mopeka app shows its level, and so does the system internally).
• See A device stopped updating.