HopeRF Pressure Sensors: How to Choose the Right Sensor for Domestic Appliance Design
- 5 hours ago
- 10 min read
Introduction: Why Pressure Sensing Matters in Modern Domestic Appliances
For most of its history, a domestic appliance did one job. A gas meter counted gas. A blood pressure monitor inflated a cuff. A coffee machine pushed water through grounds. Today, those same devices are expected to connect to the cloud, respond to safety events in real time, operate for years on a single battery, and report data accurately enough for billing purposes. Pressure sensing is central to all of it.
Whether it is detecting a gas leak before it becomes dangerous, compensating for altitude differences in a weather station, or ensuring a vacuum sealer reaches the correct negative pressure, the quality and characteristics of the pressure sensor define the performance of the whole system. Engineers specifying these components face a familiar set of trade-offs: measurement range, accuracy, power consumption, package size, and interface compatibility.
HopeRF, a Chinese manufacturer with its own ASIC design, MEMS sensor chip design, and in-house packaging and calibration capability, has developed a range of pressure sensors specifically suited to these demands. This article examines four devices available through Ineltek: the 6862i barometric pressure sensor, the HPS700A-ZM absolute pressure sensor, the HPSxxxGS gauge pressure sensor series, and the PTM002 ceramic resistive pressure transmitter.
What HopeRF's Pressure Sensor Range Addresses
The challenge for designers of domestic appliances is that "pressure sensing" covers an enormous variety of physical requirements. A smart gas meter needs a barometric sensor that can detect the subtlest pipeline fluctuations while consuming almost no power over a ten-year battery life. A blood pressure monitor needs a gauge sensor with a tight accuracy specification and a reliable MEMS structure. A coffee machine or vacuum cleaner needs something that can survive repeated pressure cycles and routine liquid exposure. A portable air pump or weather station needs a compact, waterproof absolute pressure device.
HopeRF's range maps onto these requirements with four distinct product families, each built around a 24-bit ADC, an I2C digital interface, and factory calibration so the host microcontroller receives compensated, ready-to-use data without needing to implement its own correction algorithms.
Features of HopeRF Pressure Sensors Addressing the Core Design Challenges
The 6862i: Barometric Sensing for Smart Gas Meters and IoT
The 6862i is HopeRF's digital absolute barometric pressure sensor, developed specifically with smart gas metering in mind. It uses a capacitive sensing principle which maintains high precision across temperature changes and delivers 24-bit pressure and temperature results through an I2C interface.
Its standout characteristic for battery-powered applications is power consumption. Standby current is 0.5µA (typical), which is fundamental in a gas meter expected to operate for years without a battery change. The 6862i supports three operating modes (standby, command, and background) and includes an internal FIFO buffer capable of storing up to 32 sets of measurement data. This allows the host processor to be woken infrequently to read a batch of readings rather than polling continuously leading to a significant system-level power saving.
The sensor covers a pressure range of 300mBar to 1200mBar, with absolute accuracy of ±1.0mBar and relative accuracy of ±0.1mBar. Temperature measurement is also integrated, with ±0.5°C typical accuracy and a range of -40°C to +85°C. The device is individually calibrated at the factory, with calibration coefficients stored in on-chip registers and used automatically for compensation. The waterproof design and compact 6.8 x 6.2 x 3.1mm footprint make it practical for portable and outdoor installations.
In a smart gas metering system, the 6862i does more than simply detect current pressure. When pressure drops abnormally, the system can trigger automatic valve closure, transmit alerts through an IoT module, and log data for analysis creating what HopeRF describes as a complete safety loop of detection, cutoff, alarm, and reporting. The sensor also enables pressure and temperature compensated volume calculation, which is essential for converting operating volume to standard volume for accurate billing.
The HPS700A-ZM: High-Range Absolute Pressure for Portable and Industrial Use
The HPS700A-ZM is a MEMS absolute pressure sensor with an I2C interface targeting a much higher pressure range: 0kPa to 1600kPa. This makes it suitable for portable air pumps, adventure and sports watches, weather stations, and industrial pressure and temperature monitors.
Like the 6862i, it uses a 24-bit ADC and delivers internally compensated data, removing the need for external correction on the host MCU. Standby current is below 0.1µA (even lower than the 6862i) and supply voltage spans 1.8V to 3.6V, making it compatible with a wide range of low-power embedded systems. The package is compact at 3.8 x 3.6 x 1.15mm.
Pressure absolute accuracy is ±2.0kPa over the 0 to 700kPa range from -20°C to +60°C, with relative accuracy of ±1.5kPa over the same conditions. Temperature accuracy is ±0.5°C at +25°C. The device supports I2C clock frequencies up to 400kHz and provides both compensated and uncompensated data readback options - useful in designs where the application processor may wish to apply its own post-processing. Every device is factory-calibrated for sensitivity and offset, with trim values stored in 128 bytes of on-chip NVM.
The HPS700A-ZM uses an oversampling rate (OSR) system adjustable from 128 to 4096, allowing the designer to trade conversion time and current consumption against measurement precision. At OSR 128, conversion time is 2.1ms and average pressure measurement current is 2.9µA; at OSR 4096 it rises to 65.6ms and 91.8µA. This flexibility makes it straightforward to optimise for either accuracy or power depending on the application duty cycle.
The HPSxxxGS Series: Gauge Pressure for Medical and Household Appliances
The HPSxxxGS series takes a different approach. Rather than absolute barometric sensing, these are gauge pressure sensors measuring pressure relative to ambient, available in four measurement ranges: ±10kPa, ±40kPa, ±100kPa, and ±200kPa. The corresponding part numbers are HPS010GS, HPS040GS, HPS100GS, and HPS200GS, each available in tube or reel-and-tape packaging.
The application list for this series reflects a broad set of domestic and medical equipment: electronic blood pressure monitors, oxygen concentrators, air wave therapy devices, massage chairs, air mattresses, sleep aid neck pillows, smart vacuum cleaners, vacuum juicers, beer machines, coffee machines, and vacuum pumps. The SOP6 SMD package makes board assembly straightforward, and the RoHS-compliant construction is a standard requirement for consumer product markets.
Electrically, the HPSxxxGS operates from 3.3V or 5.0V supplies, with an operating current of 1.60mA and a standby current of just 200nA. The 24-bit ADC supports oversampling rates from 256x up to 32768x, with corresponding conversion times from 1.54ms to 42.18ms. Total accuracy is ±1.5% of full scale across the -20°C to +85°C range. The I2C interface runs at up to 400kHz.
The series integrates both a MEMS pressure chip and a signal conditioning chip in a single package. Digital compensation of zero point, sensitivity, temperature drift, and nonlinearity is applied internally, so the calibrated output is directly usable by the host MCU. The output is a linear 24-bit signed value, converted to a pressure reading using a simple linear transfer function with coefficients A and B provided per part number in the datasheet.
The PTM002-2500K-G: Ceramic Resistive Pressure for Liquid and High-Pressure Applications
The PTM002-2500K-G is the most specialised product in the range. It is a ceramic resistive pressure transmitter with a stainless steel (SUS304) housing, designed specifically for direct contact with liquid media in applications such as drinking water systems, food processing equipment, and domestic life appliances.
Working pressure spans 0MPa to 2.5MPa, accuracy is ±1.0% full scale (covering linearity, hysteresis, repeatability, and calibration), and the full error band is ±2.0% full scale from 0°C to +100°C. Protective pressure is 3x full scale and burst pressure is 5x. The device is rated for over 2 million full-scale pressure cycles; a demanding specification that reflects its use in equipment that pressurises repeatedly in everyday use. IP65 protection and a G1/8 female thread pressure connection complete the mechanical specification.
Unlike the other three sensors in this overview, the PTM002 connects via a four-wire lead (red: Vcc, black: Vss, green: SCL, yellow: SDA) rather than a surface-mount footprint. The I2C interface operates with a clock frequency of up to 1MHz. Operating temperature is 0°C to +100°C and supply voltage is 1.8V to 3.6V.
Detailed Specifications: HPSxxxGS Series
Parameter | HPS010GS | HPS040GS | HPS100GS | HPS200GS |
Interface | I2C | I2C | I2C | I2C |
Pressure Range | ±10kPa | ±40kPa | ±100kPa | ±200kPa |
Pressure Type | Gauge | Gauge | Gauge | Gauge |
Package | SOP6 | SOP6 | SOP6 | SOP6 |
Supply Voltage | 3.3V / 5.0V | 3.3V / 5.0V | 3.3V / 5.0V | 3.3V / 5.0V |
Operating Current | 1.60mA | 1.60mA | 1.60mA | 1.60mA |
Standby Current | 200nA | 200nA | 200nA | 200nA |
ADC Resolution | 24-bit | 24-bit | 24-bit | 24-bit |
Total Accuracy | ±1.5% FS | ±1.5% FS | ±1.5% FS | ±1.5% FS |
Operating Temp | -20°C to +85°C | -20°C to +85°C | -20°C to +85°C | -20°C to +85°C |
OSR Range | 256x to 32768x | 256x to 32768x | 256x to 32768x | 256x to 32768x |
I2C Clock | 400kHz | 400kHz | 400kHz | 400kHz |
HPS700A-ZM and 6862i Key Specifications
Parameter | 6862i | HPS700A-ZM |
Sensor Type | Absolute barometric | Absolute pressure |
Pressure Range | 300 to 1200mBar | 0 to 1600kPa |
Pressure Absolute Accuracy | ±1.0mBar | ±2.0kPa (0–700kPa, -20°C to +60°C) |
Pressure Relative Accuracy | ±0.1mBar | ±1.5kPa |
Temperature Range | -40°C to +85°C | -40°C to +85°C |
Temperature Accuracy | ±0.5°C (typ.) | ±0.5°C at +25°C |
Supply Voltage | 1.7V to 3.6V | 1.8V to 3.6V |
Standby Current | 0.5µA (typ.) | <0.1µA |
ADC Resolution | 24-bit | 24-bit |
Interface | I2C | I2C |
FIFO | 32 measurements | No |
Package Size | 6.8 x 6.2 x 3.1mm | 3.8 x 3.6 x 1.15mm |
Waterproof | Yes | No (specified) |
PTM002-2500K-G Key Specifications
Parameter | Value |
Sensor Principle | Ceramic resistive |
Working Pressure | 0MPa to 2.5MPa |
Accuracy | ±1.0% F.S. |
Full Error Band | ±2.0% F.S. (0°C to +100°C) |
Service Life | >2 million full-scale cycles |
Supply Voltage | 1.8V to 3.6V DC |
Interface | I2C (up to 1MHz) |
Operating Temperature | 0°C to +100°C |
IP Rating | IP65 |
Housing Material | SUS304 stainless steel |
Pressure Connection | G1/8 female thread |
Operating Drift | ±0.2% F.S./year (typical) |
Industry Applications and Use Cases
Smart Gas Metering
The transition from mechanical to ultrasonic and IoT-connected gas meters is well underway across Europe. The 6862i is tailored specifically for this application. A smart gas meter integrating the 6862i can monitor pipeline pressure continuously, detect anomalies such as leaks or ruptured connections, trigger automatic valve closure, and relay alerts through a wireless module all while running from a battery expected to last several years. The sensor's FIFO buffer means the meter's MCU can spend most of its time in deep sleep, waking periodically to collect a batch of stored pressure readings rather than remaining active during measurement.
Beyond safety, the 6862i's combined pressure and temperature sensing enables accurate standard volume calculation. Gas volume varies with both temperature and barometric pressure, and regulations in many markets require that billing reflect standardised conditions rather than raw operating volume. The 6862i provides both the pressure and temperature data needed for this correction in a single package.
HopeRF also offers complementary Sub-G FSK and LoRa wireless communication solutions supporting WM-Bus and LoRaWAN networking which is a useful consideration when specifying the full meter system rather than the sensor in isolation.
Medical and Wellness Devices
The HPSxxxGS series is well suited to the medical and wellness segment. Blood pressure monitors, oxygen concentrators, and air wave therapy devices all require gauge pressure sensing in the range covered by the HPS010GS to HPS100GS. These are devices where accuracy, repeatability, and reliable MEMS construction matter alongside a compact SMD package that fits the constrained PCBs typical of consumer medical equipment.
Massage chairs, air mattresses, and sleep aid neck pillows similarly use gauge pressure sensing to regulate air chamber inflation. The 200nA standby current of the HPSxxxGS series is useful here too, in designs that spend extended periods in a monitoring or standby state between adjustment cycles.
Small Kitchen and Household Appliances
Coffee machines and other pressurised appliances present a different set of requirements: moderate pressure ranges, tolerance for repeated cycling, and interface simplicity. The HPS040GS (±40kPa) or HPS100GS (±100kPa) are natural candidates for vacuum and low-pressure applications in this category, while the ceramic resistive PTM002 is relevant where the sensing element may come into contact with liquids e.g. in drinking water systems, food processing, and similar environments where stainless steel construction and IP65 protection are necessary.
Smart vacuum cleaners also appear on the HPSxxxGS application list. Sensing the differential pressure across the filter allows the device to detect blockages and alert the user, and the SOP6 package fits easily onto the compact control PCBs typical of modern cordless vacuum designs.
Weather Stations and Portable Instruments
Compact weather stations, altimeters, and portable data loggers represent a significant application for barometric sensors. The 6862i's waterproof design and operating range down to 300mBar give it useful altitude headroom, while the HPS700A-ZM's extremely low standby current (<0.1µA) makes it an attractive choice for adventure watches and GPS devices where battery life is critical. Both devices deliver the temperature measurement needed for altitude calculation and meteorological data logging in a single component.
Conclusion and Call to Action
HopeRF's pressure sensor range gives embedded engineers a coherent toolkit for addressing the sensing requirements of modern domestic appliances. The 6862i covers barometric and gas metering applications with industry-leading standby power. The HPS700A-ZM handles high-range absolute pressure in portable and industrial instruments. The HPSxxxGS series covers gauge pressure across four ranges for medical, wellness, and household appliance markets. And the PTM002 brings ceramic resistive sensing and stainless steel construction to applications where liquid contact, high-pressure cycles, and IP-rated mechanical construction are required.
All four devices share the same fundamental architecture: a MEMS sensing element, a 24-bit ADC, factory calibration, and an I2C digital interface reducing integration risk and simplifying firmware development regardless of which variant a project demands.
Ineltek supplies HopeRF's full pressure sensor range with technical support from our field application engineers. Whether you are at the specification stage or actively evaluating components, contact us to discuss your requirements or request samples.
FAQs - HopeRF Pressure Sensors in Domestic Appliances
Q. What pressure sensor ranges does HopeRF offer for domestic appliances?
A. HopeRF offers four product families: the 6862i barometric sensor (300mBar to 1200mBar), the HPS700A-ZM absolute pressure sensor (0kPa to 1600kPa), the HPSxxxGS gauge pressure series (±10kPa, ±40kPa, ±100kPa, or ±200kPa), and the PTM002 ceramic resistive transmitter (0MPa to 2.5MPa). Each uses a 24-bit ADC and an I2C digital interface.
Q. What is the standby current of the HopeRF 6862i pressure sensor?
A. The 6862i has a standby current of 0.5µA (typical), making it well suited to battery-powered smart gas meters and IoT devices designed for years of unattended operation.
Q. Which HopeRF pressure sensor is suitable for a blood pressure monitor or medical device?
A. The HPSxxxGS gauge pressure series is specifically listed for intelligent electronic blood pressure monitors, oxygen concentrators, and air wave therapy devices. Available in four ranges (±10kPa to ±200kPa) in a compact SOP6 SMD package with 24-bit resolution and internal temperature compensation.
Q. Can HopeRF pressure sensors be used in food processing or drinking water applications?
A. The PTM002-2500K-G is designed for this purpose. It features a ceramic resistive sensing core, SUS304 stainless steel housing, corrosion-resistant seals, and IP65 protection, and is explicitly specified for domestic life appliances, drinking water systems, and food processing equipment.
Q. Do HopeRF pressure sensors require external calibration?
A. No. Each device is individually factory-calibrated, with calibration coefficients or trim values stored in on-chip non-volatile memory. The internal signal conditioning provides temperature-compensated, linearised digital output directly via I2C, removing the need for user calibration or complex compensation firmware.
