I used to work for Volvo, developing the maps for ECUs for engine control. One of my colleagues wanted a simple indicator showing the injection time, i.e. for how many milliseconds each engine revolution the injectors were open, to see how his mapping was working out in practice when test driving. He asked for help from the electronics lab, who came up with a proposal for a digital display, all-singing, all-dancing precision device which would cost $$$$$, come in a nice 19" case and take months to design. He went off and made his own indicator instead, using a 555, a moving-coil meter and some passive components. Quite a number of his devices were built for everybody else in the department, IIRC. /Jonas