Requirements for MerlinStep arose from long-time experience:
- possible matching of more modules under one remote control
- minimal consumption with the internal battery
- simple firing by buttons with the possibility of sequence programming
- water resistance of the firing module against falling water and snow
- low and high temperatures stability
- setting the module in the MS Windows environment, possibility of data filing
- firing accuracy to 0.001 s, setup of the firing by 0.01 s
- easy maintenance, no external sources
Firstly, the package consists of the control-module pair where the handling is as demanding as changing the programmes on television with the remote control. Working frequency is in the 868 MHz band (optionally 433 MHz), transmitted data are secured by a floating code with a high-level safety. Technical high-frequency parameters correspond to the norms for transmission in this band and the range of the package complies with it. In order to reach a reliable transmission, we decided for this rather high frequency where there is not high interference of other transmitters. In spite of this, the overall range of the control is given not only by the distance from the firing module, but also by wall shading (reinforced concrete), environment and even by the way we hold the control in our hands. During tests a reliable connection was reached in the distance of more than one kilometre in open space, which is sufficient enough for a common firing of fireworks, because we need to have the location under a visual control. We cannot fire the explosives if somebody is moving, though by mistake, in the safety area of firing.