Pressure Sensors

Pressure sensors measure the pressure against a surface. They can be used to measure the pressure of a gas, fluid or solid.

Pressure Sensing Film

Pressure sensing film is a material which permanently changes colour based on applied pressure. The only manufacturer I am aware of that makes this is Fujifilm with their “Prescale” brand. The film contains microcapsules of colour-forming material. When broken under pressure, they react with colour-developing material, causing the film to change from white to a magenta colour (as shown in the image below). The colour intensity (which is referred to as the colour density) is proportional to the pressure applied.

How Prescale pressure sensing film works.¹

There are the following products in the Prescale range:²

Product (code)	Pressure range	Type	Roll-type Product Size	Sheet-type Product Size
Ultra extreme low pressure (5LW)	0.006-0.05 MPa	Dual-sheet	320 mm x 2 m	-
Extreme low pressure (4LW)	0.05-0.2 MPa	Dual-sheet	320 mm x 3 m	-
Ultra super low pressure (LLLW)	0.2 - 0.6 MPa	Dual-sheet	270 mm x 5 m	270 x 200 mm (5 sheets)
Super low pressure (LLW)	0.5 - 2.5 MPa	Dual-sheet	270 mm x 6 m	270 x 200 mm (5 sheets)
Low pressure (LW)	2.5 - 10 MPa	Dual-sheet	270 mm x 10 m	270 x 200 mm (5 sheets)
Medium pressure (MW)	10 - 50 MPa	Dual-sheet	270 mm x 10 m	-
Medium pressure (MS)	10 - 50 MPa	Mono-sheet	270 mm x 10 m	270 x 200 mm (5 sheets)
Higher pressure (HS)	50 - 130 MPa	Mono-sheet	270 mm x 10 m	270 x 200 mm (5 sheets)
Super high pressure (HHS)	130 - 300 MPa	Mono-sheet	270 mm x 10 m	270 x 200 mm (5 sheets)

All of the dual-sheet product codes end in W and all of the mono-sheet product codes end in S. The dual-sheet products come with an A film and a C film. The A film contains the colour-forming material (microcapsules) and the C film is coated with a colour-developing material. The coated sides of these films must be facing each other. When getting an intuitive sense for pressures, it’s useful to remember that $1\,\text{MPa} = 1\,\text{N/mm}^2 = 10\,\text{kgf/cm}^2$.

To convert from colour density to pressure, charts are given which provide a mapping at various temperature and humidity conditions. The film is quite sensitive to both temperature and humidity, so it is important to take these into account when using the charts.

Charts for converting from colour density to pressure for the LLW Prescale film.³

There is also special film in the Prescale range for operating at high temperatures (180 - 220°C). It appears that it is only available in the LLW pressure range (0.5 - 2.5 MPa).¹

Examples

Honeywell ABP2 Series

The Honeywell ABP2 series is a family of board-mount pressure sensors. There are both through-hole and SMD versions. They detect pressure using piezoresistive silicon and offer both analogue and digital output options (digital versions support either the I2C or SPI bus protocols). Options exist to both measure gas and liquid (there is an additional gel coating added to the liquid versions).⁴

A photo of the various variants of the Honeywell ABP2 series pressure sensors.⁵

You have to be careful when both soldering and handling these sensors. They are particularly sensitive to over-heating (the plastic parts and/or sealant can melt) during soldering. The plastic barb can also be torn of the rest of the component easily it too much torque/force is applied from the connected hose.

A photo of 3 Honeywell ABP2LAN air pressure sensors mounted on a PCB. Two are connected to hoses (with some sealant applied), one is not.

Footnotes

1. Fujifilm (2022). Visual Material Solutions - Measuring pressure, heat or UV light easily with each film. [product catalog]. Retrieved 2026-04-20, on file with author. ↩ ↩²

2. Fujifilm. Prescale - Pressure measurement film [product page]. Fujifilm New Zealand. Retrieved 2026-04-20, from https://www.fujifilm.com/nz/en/business/inspection/measurement-film/ps. ↩

3. Fujifilm (2017). Prescale LLW Instruction Manual [instruction manual]. Retrieved 2026-04-20, on file with author. ↩

4. Honeywell. Basic ABP2 Series Board Mount Pressure Sensor [product page]. Retrieved 2025-01-16, from https://automation.honeywell.com/us/en/products/sensing-solutions/sensors/pressure-sensors/board-mount-pressure-amplified/basic-abp2-series-board-mount-pressure-sensor. ↩

5. Honeywell (2025, Oct). ABP2 SERIES - Board Mount Pressure Sensors [datasheet]. Retrieved 2025-01-16, from https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-au/products/sensors/pressure-sensors/board-mount-pressure-sensors/basic-abp2-series/documents/sps-siot-abp2-series-datasheet-32350268-en.pdf. ↩