Wirelessly Linking a Mobile Device to a Microcontroller

Mobile devices have permeated deeply into our daily living and activities. Microcontrollers are tiny, self-contained computers embedded into numerous electronic and electrical products. Microcontrollers are frequently used as the “silicon brain” for controlling products that we use daily, for examples, digital thermostats, garage door openers, power tools, kitchen stoves, etc. It is desirable to establish wireless connection between a mobile device and a microcontroller so that through a mobile device a user can initiate control actions for operating the electronic and electrical products that are embedded with microcontrollers. We have made such attempt for establishing a wireless communication link between an Android tablet/cellphone and a Freescale (formerly Motorola) microcontroller embedded in an electronic product. This was done in an undergraduate engineering project conducted in Summer 2014 and we have successfully established such link. Specifically, the electronic device is a speed measurement instrument controller by a Freescale microcontroller. We build this instrument in our microcontroller applications course. The mobile devices are a Samsung Galaxy Pro tablet and a Samsung Galaxy S3 cellphone. Building upon Bluetooth technology we developed an Android app that runs on the tablet and the cellphone. Through the app the Android devices can reach into the Freescale microcontroller embedded in the speed measurement instrument wirelessly and captures the speed readings stored in the microcontroller. The app then displays these readings on the tablet and the cellphone screens. A benefit of our project is that the display panel of the instrument can be replaced by those of the Android devices and that will reduce the cost of the instrument. We were also able to transmit commands to the instrument. With necessary modification this app can be adapted to control other electronic or educational devices. In the symposium we are planning to present the details of this project and give a demonstration