Introduction

This innovative sensor (TRL 4) relies on an optical working principle in order to sense pressure variation over its surface. Such a load cell is constituted by one or more photoresistors embedded in the main body of the sensor. The sensor is in contact with a light source through elastic transparent hemispherical parts placed in front of the photoresistors.

Technical features

The readings are obtained by measuring the voltage drop across the photoresistor, which is proportional to the collected light, that depends on the area of contact between the cylindrical light source and the hemispherical elastic part. Multiple sensors can be in contact with a single light source according to the purpose and to the required level of detail. Through the device, it is possible to detect the hands activity on the device. One can detect unwanted actions and correct them, detect a loss of grip, or warn the user of an incorrect hand position. It is possible in general, to have a real time data set that is usually unavailable, with a low-cost device that does not interfere with the user experience.

Possible Applications

• Human machine coupling;
• Vehicle steering (automobile, bulldozer, aircraft, rotorcraft, power tools);
• Physiotherapy (eg. enhancement of hand and pelvic floor muscle training and recovery experience).

Advantages

• Can easily be integrated in an input device to monitor hand activity without altering user experience;
• Measurement are not altered by changes in electromagnetic fields or temperature;
• Size can vary from a few millimeters to as much as needed thanks to the possibility to have multiple photoresistors embedded in one load cell.