Målet med detta examensarbete är att ersätta den tidigare lösningen av sensorfingret med andra komponenter, eller hitta en annan sensor med motsvarande funktion.Arbetet har begränsats av att ESAB vill ha ett mekaniskt finger för användarvänlighetens skull. Efter en förundersökning av olika typer av sensorer har vi valt att använda oss av trådtöjningsgivare som sensorer till det mekaniska sensorfingret. I och med detta val behövde vi även komma med ett teoretiskt förslag på en mekanisk upphängning av sensorfingret.Vi har byggt upp två separata Wheatstonebryggor med varsin instrumentförstärkare (INA125). Utsignalen från bryggorna är relativt liten och behövde förstärkas cirka 2000 gånger.Nollbalansering av bryggorna har skett manuellt med potentiometrar men vi har även gett ett förslag på en lösning där nollbalansering kan ske med ett enkelt knapptryck. Knappen är placerad på upphängningen på ett sådant sätt att man inte kan trycka oavsiktligt på knappen.Resultatet av arbetet är en uppkoppling på en experimentplatta samt förslag på hur upphängningen och sensorfingret designmässigt kan se ut.För vidare arbetsgång behövs en prototyp för att testa livslängden och ta reda på vilken känslighet som är mest optimal..

This bachelor thesis is about an ultrasonic sensor, implemented in a bubble chamber in Artis. The sensor consists of the piezoelectric sensor and an electronic control circuit. The control circuit consists of a programmable microprocessor, PIC18F2420 and a circuit, which sends the excitation signal to the piezoelectric sensor, and later receives the echo. This bachelor thesis consists also of a theoretical study, which examines different techniques of liquid level sensing in a chamber. The study discusses which factors are important in liquid level sensing and examine accepted methods.

The interest in tiny wireless applications raises the demand for an integrated reference oscillator with the same performance as the macroscopic quartz crystal reference oscillators. The main challenge of the thesis is to prove that it is possible to build a MEMS based oscillator that approaches the accuracy level of existing quartz crystal oscillators. The MEMS resonator samples which Philips provides are measured and an equivalent electrical model is designed for them. This model is used in the simulations of the Pierce oscillator and the transresistance Amplifier oscillator that are evaluated in this thesis. Finally the Pierce oscillator is implemented in the A BCD2 process and manufactured at Philips Semiconductors in Nijmegen, The Netherlands.

This study was conducted at a special school for children with autism and developmental disabilities. The study consists of three interviews where pedagogues have different experiences of working with children in need of special support. The aim is to get an idea of how teachers think about working with children autism, but above all to find out what methods and educational tools that are used, and why they are used to best motivate students to a rewarding education. Sense of coherence (SOC) is a central concept and a theoretical basis of the study relating to the student to create comprehensibility, manageability and meaningfulness in life. All of these three are essential for the student to find a predictable environment.From the result shows how schools and teachers use different methods and different tools, but both have a focus to help the student find motivation in the learning process.

A large part of the interactions between horse and rider during horseback riding takes place through the reins and the bit and devices for measuring the tension on the reins, rein tension meters, has fairly recently been developed. To safeguard the welfare of the ridden horse riders need to be aware of the rein tension they apply and actively work to decrease it. Furthermore, there is a need to develop the study of rein tension through new techniques and refined analysis procedures. A good-quality rein tension meter should be small in size, sensitive, durable and as accurate for light rein tension as for strong forces. Rein tension meters used in research on horse and rider interaction commonly depend on strain gauge technique for generating rein tension data.