Hydrogen Leak and Environmental Sensor

Metis Engineering H Guard

H Guard is a CAN based sensor that can measure absolute pressure, air temperature, H2 (Hydrogen), absolute air water content, relative humidity, dew point temperature and 3 axis acceleration.

  • Absolute Pressure: 0.3 to 1.2 Bar
  • Air Temperature: -40°C to +125°C
  • Relative Humidity: 0% to 100%
  • Dew Point Temperature: 0 to 100°C
  • Accelerometer Range: -24 to +24g

Introducing the H Guard, an advanced CAN-based hydrogen leak and environmental sensor for automotive and energy systems. The H Guard sensor is a compact, CAN-based multi-sensor module designed to monitor critical environmental and safety parameters in hydrogen and energy storage systems. It precisely measures absolute pressure, air temperature, hydrogen (H₂) concentration, absolute air moisture content, relative humidity, dew point temperature, and 3-axis acceleration—making it ideal for detecting hydrogen leaks or early battery pack failures caused by cell venting or moisture formation.

Featuring a configurable CAN bus speed and address, and supplied with a CAN DBC file, the H Guard enables seamless integration into virtually any hydrogen-powered system, EV, or battery application. The device includes a low-power monitoring mode that minimizes energy consumption by suspending CAN transmissions until a predefined threshold is reached, at which point it automatically switches to active mode. A low-side drive output pin (500mA capable) is also included and can be activated by a wake signal, enhancing system response in critical situations.

Engineered for automotive environments, the sensor is housed in a rugged design with a 5-pin automotive-grade Molex Nano-Fit Power connector. Its small form factor and low mass make it easy to install in electric vehicles, hydrogen fuel cell systems, and stationary energy storage units. Developed in accordance with ISO 26262 functional safety standards, the H Guard has been rigorously tested to meet automotive EMC and environmental requirements including ISO 7637-2:2011, ISO 16750-2:2012, and ISO 16750-4:2010. An ATEX certification is currently in progress, expanding its applicability to explosive atmospheres.

Key Features of the H Guard:

  • Absolute Pressure: 0.3 to 1.2 Bar
  • Air Temperature: -40°C to +125°C
  • Absolute Humidity: 0 to 35000mg/m3
  • Relative Humidity: 0% to 100%
  • Dew Point Temperature: 0 to 100°C
  • Accelerometer Range: -24 to +24g
  • Operating Temperature: -40 to +85°C

Typical applications for the H Guard:

  • Battery Packs in Energy Storage Systems
  • Battery Packs in Electric Vehicles
  • Hydrogen Fuel Cell Systems
  • Accurate Environmental Sensing in Aerospace & Defence Applications

Unit Specifications

SensorAttributeValue
Pressure SensorRange0.3 Bar to 1.2 Bar
Pressure SensorResolution0.0001 Bar
Pressure SensorAccuracy (0.3 to 1.1 Bar)0.0005 Bar
Pressure SensorMax Update Rate50Hz
Air Temperature [1]Range-40°C to 125°C
Air Temperature [1]Resolution1°C
Air Temperature [1]Accuracy (@ 24VDC)±2°C
Air Temperature [1]Max Update Rate5Hz
Absolute Humidity [3]Range0 to 35000mg/m3
Absolute Humidity [3]Resolution70mg/m3
Absolute Humidity [3]Accuracy (Worse Case)5% FSS
Absolute Humidity [3]Max Update Rate5Hz
Dew PointRange0°C to 100°C
Dew PointResolution0.5°C
Dew PointAccuracy (Worse Case)±3°C
Dew PointMax Update Rate5Hz
Relative HumidityRange0% to 100%
Relative HumidityResolution0.5%
Relative HumidityAccuracy (Worse Case)3%
Relative HumidityMax Update Rate5Hz
Accelerometer [4]Range-24g to +24g
Accelerometer [4]Resolution0.01g
Accelerometer [4]Accuracy (Worse Case)0.1g
Accelerometer [4]Max Update Rate200Hz
Environment[5] Operating temperature-40°C to +85°C
CANBaud Rates [6]1000, 500, 250 & 125kbps
CANAddress Range [7]1 (0x01) to 2042 (0x7FA). Default = 0x30A decimal (Hex)
PowerVoltage Range9 to 32 VDC
PowerCurrent (silent mode/low power @12V)24mA (0.75 mA)
HydrogenRange-40°C to +125°C
HydrogenResolution0.002%
HydrogenAccuracy0.4 vol% + 10% m.v.
HydrogenMax Update Rate(Response Time: τ(63) <1s) Hz

[1] Air Temperature accuracy is dependent on installation, heat from the sensor itself can affect this
[2] Humidity accuracy valid from 0 to 80 deg C IC temperature and 5 to 95% RH
[3] Not normally fitted, only on variant with accelerometer option selected
[4] The default settings are 500kbps and start address 778 (0x30A), the unit has no CAN termination
[5] The unit uses up to 5 CAN address which are in consecutive order from address that the unit is set to
[6] The function pin is protected to transients up to 40VDC but is not current limited, please ensure load is not above 500mA
[7] The function of this pin is assigned when configuring the unit please refer to the manual
[8] Only the range of 9-16V has been tested to ISO standards. Outside of this range is not tested to ISO standards.

Specifications

Weight 15 kg
Dimensions 11.5 x 50 x 54.5mm
Series / Model

Accelerometer

Not Fitted, Triple Axis ±24g

Pressure Range

Gas

H2

Version

Full Wake Features, No Wake Feature on Gas

Temperature Range (°C)

-40 to +85°C

Supply Voltage

9 to 32Vdc

Ordering Info

Below is the model number configuration for the HG series from ​Metis Engineering Ltd.
Ordering example: HG-A1-P1-G1-H1-V1
HGAXPXG1H1VX

Series / Model (HG)

HG
HG

Accelerometer (AX)

A0
Not Fitted
A1
Triple Axis ±24g

Pressure Range (PX)

P1
0.3 - 1.2 Bar

Gas (G1)

      G1 – H2

Humidity (H1)

      H1 – Humidity 5% – 95%

Version (VX)

V1
Full Wake Features
V2
No Wake Feature on Gas

Product Variations

SKUAccelerometerPressure RangeVersion
HG-A0-P1-G1-H1-V1Not Fitted0.3 - 1.2 BarFull Wake Features
HG-A0-P1-G1-H1-V2Not Fitted0.3 - 1.2 BarNo Wake Feature on Gas
HG-A1-P1-G1-H1-V1Triple Axis ±24g0.3 - 1.2 BarFull Wake Features
HG-A1-P1-G1-H1-V2Triple Axis ±24g0.3 - 1.2 BarNo Wake Feature on Gas

Resources

Product Datasheet

Supporting Product Information

Metis Engineering H Guard

Hydrogen Leak and Environmental Sensor

Metis Engineering H Guard

£105.60£132.00

Select at least 2 products
to compare