Measure brake fluid levels

Brake cylinder and combination brake fluid reservoir:

https://www.wilwood.com/MasterCylinders/MasterCylinderProd?itemno=260-15096

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Reservoir Size: 1.5 oz

Compatible brake fluid: Wilwood Hi-Temp 570: https://www.wilwood.com/BrakeFluid/BrakeFluid

• Dry Boiling Point: 573 °F(300 C)    Wet Boiling Point: 313 °F (156 C)

Possible Sensor with the change to the non-integrated reservoir compact cylinder:

Compact Master Cylinder:

https://www.wilwood.com/MasterCylinders/MasterCylinderList?group=GS Compact Remote Master Cylinder

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Master Cylinder Reservoir Caps with Electronic Fluid Level Sensors made by Wilwood(manufacturer of the fluid cylinder: https://www.wilwood.com/PDF/Flyers/fl316.pdf

• Smallest Compatible Reservoir Size (pictured above): 4oz

Almost Compatible Sensors for Existing Cylinder

Types of fluid level sensors

https://cecas.clemson.edu/cvel/auto/sensors/fluid-level.html

https://new.abb.com/products/measurement-products/level/a-dozen-ways-to-measure-fluid-level

More info about sensors with larger gradients

https://www.fierceelectronics.com/components/fluid-level-sensors-more-than-just-off-signal

Sourcing of different sensors

https://www.mouser.ca/Sensors/Liquid-Level-Sensors/_/N-zqig

https://www.mcmaster.com/liquid-level-sensors/

Pros and cons of the ultrasonic fluid sensor

https://www.fluidswitch.com/2015/10/23/pros-cons-ultrasonic-level-sensors/

• emits a high-frequency pulse of ultrasonic sound then records the time it takes for the echo to return. Based on the speed of sound, the distance from the sensor to the top of the liquid media can be calculated by dividing the time between the initial pulse and its echo by two

• Pros:

  • Works well with mediums where contact is not ideal(boiling and corrosive liquids)

  • Can produce continuous measurements

• Cons:

  • Bad with materials that absorb the ultrasonic waves instead of reflecting it

  • Gets less accurate as the depth of the tank and liquid increases

Float Switches - These sensors employ a magnetic float that moves with the liquid surface, actuating a hermetically sealed "reed switch" in the stem. 

Pros:

• Simple so relatively low maintenance and reliable

• Works for many fluids

• Works in many conditions(shock, vibration, pressure)

• Cheapest with simple designs and construction

Cons:

• Sticky or thick liquids may cause the float to become stuck

• Moving parts mean more maintenance 

Capacitance Level Sensors - Capacitance sensors sense a change in the capacitance that occurs between two conductors when fluid is present. 

Pros

•  Can operate at extreme temperatures and pressures

Cons:

• Intrusive measuring equipment

• May not work well with different chemicals due to coating of rods and or tank wall 

• Thick liquids coating the rod may cause large errors

Differential Pressure Sensor- monitors the fluid level by measuring the total pressure difference between the fluid at the bottom of the tank and the vessel pressure.

Pros:

• Can be used in pressurized or unpressurized tanks

• Can be installed/retrofitted to existing systems 

Cons:

• The density of the liquid can affect the accuracy of readings

• Temperature changes can change readings

Therefore this probably eliminates this type of sensor as well as the capacitance sensor as brake fluid is relatively thick and changes density as it is used more. Also, the temperature of the fluid changes as you run the car and affects the pressure of the tank unless vented so it may cause pressure readings to be inaccurate.