The field of automation and smart devices is currently expanding. As most devices require wireless communication, the market for low budget, low power radios is growing rapidly. Many applications, such as the remote control of machines, have real time requirements with minimal latency. In this report, the market of wireless chips in the sub-GHz region has been investigated in order to give Syntronic AB an insight of the current market. Several key features such as range, data rate and output power were ranked among the available chips. To provide Syntronic with a marketing tool when reaching out to customers in the remote control field, a demonstration prototype (demo) was implemented using one of the radio chips from the list. The demo shows real time requirements with low latency between two wireless nodes. The first node takes movement data from a computer mouse and transmits it to the other node controlling an array of light emitting diodes (LEDs). This report contains the selection of radio configurations, design of a new wireless communications protocol, and implementation of the system in hardware and software. Measurements show a latency of 3.6 ms and a range of approximately 450 m which is regarded satisfactory.

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Bar code stores information in the form of series of bars and gaps with various widths, and therefore can be considered as an example of bilevel (square) signal. Magnetic bar codes are created by applying slightly ferromagnetic material to a substrate. Sensing is done by reading oscillator, whose frequency is modulated by presence of the mentioned ferromagnetic material. Signal from the oscillator is then subjected to frequency demodulation. Due to temperature drift of the reading oscillator, the demodulated signal is accompanied by DC drift. Method for removal of the drift is introduced. Also, drift-insensitive detection of presence of a bar code is described. Reading bar codes is complicated by convolutional distortion, which is result of spatially dispersed sensitivity of the sensor. Effect of the convolutional distortion is analogous to low-pass filtering, causing edges to be smoothed and overlapped, and making their detection difficult. Characteristics of convolutional distortion can be summarized into point-spread function (PSF). In case of magnetic bar codes, the shape of the PSF can be known in advance, but not its width of DC transfer. Methods for estimation of these parameters are discussed. The signal needs to be reconstructed (into original bilevel form) before decoding can take place. Variational methods provide effective way. Their core idea is to reformulate reconstruction as an optimization problem of functional minimization. The functional can be extended by other functionals (regularizations) in order to considerably improve results of reconstruction. Principle of variational methods will be shown, including examples of use of various regularizations. All algorithm and methods (including frequency demodulation of signal from reading oscillator) are digital. They are implemented as a program for a microcontroller from the PIC32 family, which offers high computing power, so that even blind deconvolution (when the real PSF also needs to be found) can be finished in a few seconds. The microcontroller is part of magnetic bar code reader, whose hardware allows the read information to be transferred to personal computer via the PS/2 interface or USB (by emulating key presses on virtual keyboard), or shown on display.