Inertial measurement units, or IMUs, serve as effective tracking devices when used in sophisticated aerospace control and navigational systems. This tracking potential, coupled with ever advancing technology that permits IMUs to become smaller and more compact, is allowing IMUs to gain popularity in a many areas of research beyond the areas of aerospace. Using an IMU based on microelectromechanical (MEMS) technology, this document investigates an IMU’s ability to track complex, short range motions such as golf swings. To prepare the IMU, an accurate, yet quick, calibration procedure is proposed and illustrated to show the tools and equipment necessary for this approach. Once calibrated, experimental results from static and dynamic tests are compared to corresponding analytical results to help comprehend and confirm the IMU readings. The IMU is then applied to a series of short range motions for reliability and performance testing.

DD Company AB wanted to improve their existing products the football training rebounding board PAL and their PAL Cones. Their suggested solution was to create an application which communicates with PAL and PAL Cones via Bluetooth. The goal was to have an app which can record how many times PAL has been hit during a set time span and control PAL Cones to indicate to the player to step on a specific cone. PAL's problem was solved by on it place a base unit made of an accelerometer to sense impacts, a BLE112 Bluetooth module to communicate over Bluetooth and an Arduino UNO for reading the accelerometer and signal the Bluetooth module which transmits a hit counter over Bluetooth to the mobile application. The PAL Cone uses only the BLE112, a LED, a button and a button cell battery to keep the size to a minimum. The base unit is able to filter the initial impact from the residual vibrations and sends a updating hit counter over a Bluetooth connection to the mobile application. The mobile application can control the counter by sending commands to the base unit. After a hit the mobile application can activate a cone to light up and receives feedback when a player steps on the specified cone.

This thesis aims at developing a prototype for a fall detection bracelet that can connect to the cellular network. The bracelet consists of a processing unit, three sensors, a LTE USB modem and a powerbank. The prototype is aimed at elderly people since up to one out of three over the age of 65-years-old fall each year. Besides elderly people this system can be used in activities which involves substantial height, e.g. climbing and roofing. Statistics has shown that most serious consequences are not a direct result of falling, but from the lack of fast assistance and treatment. If a fall is detected a distress signal, in the form of an SMS message, is sent to a predefined emergency contact. The contents of the SMS messages includes time and date of fall, ambient temperature, fall location coordinates as well as an URL that redirects to the location as seen in Google Maps. The fall detection algorithm is threshold based and was created by first analyzing falls in different direction. It can successfully identify 74,4% of all falls, but as good as up to 91% of falls that are either backwards, forwards or to the left given that the bracelet is attached to the left wrist. The algorithm can further filter out 100% of studied activities that are not falls. Such activities include walking, running and sitting down. This gives an overall Accuracy of 93% for the system. The Accuracy takes into account how well a fall is detected and how well other activities are filtered out. Furthermore, the bracelet was worn for 40 hours, spread out over 11 days, in order to capture data during this persons every day life. During this time no false distress signal was sent to the emergency contact. Limitations of the system has been found to be the GPS module and the fact that the algorithm is threshold based. The location tracking can be improved by utilizing AGPS, which is the same technique that cellphones use. The threshold based system can't be circumvent in a wearable device solution. From this thesis it is indicated that a wearable bracelet can be a reliable fall detection unit. With more extensive falls and field testing even better results can be achieved and it can eventually be pushed as a real product.

This master’s thesis describes a wireless accelerometer module. The aim of this work was to study the properties and involvement of the accelerometer, wireless module design for data transfering from the accelerometer to the PC and the module implementation. As a wireless device is used bluetooth module that enables communication between the product and the computer. The wireless module used rechargable lithium ion battery that helps keep module alive without adapter or net cable.