HC-50 Node

HydroConnect HC-50 Node (measuring station)

The HC-50 measuring station (also called node) records your readings and sends them via LoRa radio to a gateway. It works independently of mains and location with an HC-50 battery and, like the gateway, sits in a 50 mm HT pipe.

The essentials in brief

• The node needs no WiFi and no power connection. It needs a gateway within radio range, typically several kilometres.
• It sleeps between two measurements and uses hardly any power while doing so. The less often it measures, the longer the battery lasts.
• You choose the sensors to suit the place of use: water level, water quality, weather data and more.
• A firmware update is possible via Bluetooth, without opening the housing.

Compared with the gateway, the node additionally has:

• a holder for the HC-50 battery
• a holder for the HC-50 solar module _{(in development)}
• contactless magnetic switches for maintenance purposes
• optionally the "Paxcounter" sensor (visitor density)

Design

A node consists of several modules that sit one above the other in the pipe: antenna, main module with radio and processor, battery and sensor module. Depending on the purpose, sensor carriers are added, which are attached to the side or bottom of the pipe. The illustrations show a measuring station with sensor arm and underwater probe as a CAD model (the pipes are shown transparent).

Installation

Location and mounting

Thanks to the 50 mm HT pipe, the node can be fastened in many ways, e.g. with pipe clamps on a mast, a railing or a wall. The radio link is what matters:

• The gateway must be reachable directly. The node does not transmit via other stations.
• An open location without large metal surfaces nearby improves the range. More on this under LoRa radio technology.
• Whether the connection works can be seen in the cloud: as soon as the node has sent values, it appears there.

Use in water

Special care is required in water:

• The horizontal sensor arm (if present) must under no circumstances go below the highest possible water level. Otherwise the station can be irreparably damaged.
• The length of the vertical measuring probe and the protective tube must suit the body of water. The protective tube protects the probe from floating debris and still lets the water flow through.
• The probe should hang in mid-water and must not run dry even at the lowest water level.

Insert the battery

Insert the HC-50 battery into the station from above. It is protected against reverse polarity and clicks into place. More on this on the page HC-50 battery.

Sensors

Like the gateway, the measuring station can be equipped with antennas and sensors. Adapt the equipment to the place of use and purpose. In a still body of water, for example, a flow velocity measurement makes little sense.

In addition to the gateway's sensors there are two kinds of sensor carriers.

Horizontal sensor carrier (sensor arm)

The sensor arm sits above the water surface and holds:

• distance measurement for the water level (ultrasonic)
• BME280 for air temperature, humidity and air pressure

Vertical underwater carrier (measuring probe)

The underwater carrier dips into the water and holds:

• pH probe
• temperature sensor
• EC sensor (conductivity)
• turbidity sensor

The sensors for pH value and water level are in development. The cloud shows which sensors your station currently evaluates.

Paxcounter (visitor density)

The Paxcounter counts how many people pass an area. To do so it detects WiFi and Bluetooth signals from devices in the surroundings. This can be used, for example, to record visitor numbers in a park.

The Paxcounter has a drawback: the station must stay in continuous operation and cannot sleep between measurements. Power consumption is therefore considerably higher. So use it with a power supply instead of a battery wherever possible.

Power supply

The node runs on the HC-50 battery. The station monitors its battery status and warns in good time of an energy deficit. How long a battery lasts depends on the measuring interval and the number of sensors. More on this under Power supply.

A solar module with integrated battery will also be available soon. At suitable locations a measuring station can then work completely autonomously, without batteries having to be replaced.

Maintenance

The maintenance effort depends on the location and the sensors. A temperature sensor is largely maintenance-free, a pH sensor needs considerably more care. Follow the maintenance instructions of the respective sensor.

When changing the battery, a short visual check is a good idea: are the housing and seals undamaged, is everything dry, has nothing settled in?

Update the firmware

The node's firmware is updated via Bluetooth with the smartphone, without opening the housing. Since the node usually sleeps, the update mode has to be requested beforehand. Alternatively an update via USB cable is possible.

Detailed guide: Firmware features

Technical data