Low cost position sensor

Several developments are on-going and targeting an accuracy above 10 bits, however no development and no product in the market is currently covering low accuracy. There is a clear need for this type of sensors as for many applications that need low or medium accuracy sensors, cost is normally an important factor. To fit this type of applications, current mechanisms use potentiometers, which are easy to integrate and cheap compared to other products, however, they are prone to noise and limited life because of their technology, based on sliding electrical contact. 

During the 2018 harmonisation exercise for position sensors, ESA saw the need for such a development and already industry has provided their interest in performing such an activity. 

The aim of this activity was to develop a sensor that can provide an alternative to potentiometers without their noise issues. The activity was conducted with EMBEDDED INSTRUMENTS AND SYSTEMS SLand ALTER TECHNOLOGY TUV NORD S.A. in Spain. Many applications need low or medium accuracy reliable sensing solutions. To fit this type of applications, current mechanisms use frequently potentiometers, which have a very competitive price compared to other products, however, they are prone to noise and limited life because of their technology, based on sliding electrical contact. Therefore, there is a clear interest in developing a low cost position sensor in the low accuracy range that can provide reliable performance through the entire lifetime for a competitive price.
The sensor design was targeting low cost (<5000€), low accuracy (8 to 10 bits) and high reliability. Two technologies were studied, capacitive and inductive. Both technologies will make use of very simple electronics to reduce the cost.
The final breadboard for a low cost position sensor based on capacitive technology provides a repetitive 10 bit accuracy that can be used as a replacement for potentiometers.