Thomas Koster's first electronic timers were F1C units. I remember seeing his first attempts in 1977 at the Danish World Championships. His initial efforts were really electro-mechanical, with a geared electric motor running continuously during the power run and then waiting electronically, using an analog 555-type chip, until d/t time. One evening during the World Championships Thomas and I had a detailed discussion about the things he'd tried and why they'd all been unreliable. At the time he'd moved onto electronic engine run as well as d/t timing but still used a geared motor and disk stack to sequence the engine stop and trim changes during the transition from power to glide. At the time he still hadn't solved the problem of finding a way to set the timer that could survive the engine vibration for more than one or two flights.
In 1981 he showed up with the first successful solution in Spain. These timers had dumb onboard electronics and a bulky microprocessor- based control box to set them. All settings were permanently stored in the control box and downloaded into the model before flight: removing power from the timer cleared its memory. Moving the setting system off the model solved his reliability problem. Those timers had a 256 x 1 bit RAM memory to store the settings and a servo that turned a disk in steps, releasing a lever on each step. The clock initially ticked 10 times a second. Each tick stepped the RAM address and each set bit in the RAM incremented a sequence counter whose output moved the servo on a step, releasing the next lever. The setting accuracy during the power run was 0.1 seconds. At the last power to glide transition step it also changed the clock rate from 10 ticks per second to 4 seconds per tick for d/t timing. These timers also marked a move to CMOS chip technology and had to be potted in epoxy to work: Thomas found out the hard way that methanol vapour from glow fuel increased the conductivity of air to the point that a bare CMOS chip would self-trigger due to conductance between adjacent pins.
In 1987 Thomas appeared in Maniago with the definitive F1C timer. This retained the external control box concept, but moved the microprocessor into the model. Power consumption was much reduced and the control box became essentially a dumb terminal, displaying settings and menus sent to it by the timer. All his subsequent developments were variations on this theme, which also forms the basis of the current MultiClass timer. Until about 2005 this was sold by Torleif Jensen, who was very much part of its development process from 1987 onwards. Since then its been further developed and is sold by Christoph Bachmann, though Torleif's web site still appears to be the main information source for them.
The next significant F1C timer development was the Mogle, designed as a drop-in replacement for a Seelig F1C timer. This allows you to retrofit an electronic timer to an existing model with minimal changes.
In 2008 the Sidus F1C timer was launched as a serious attempt to make electronic timers more available for F1C models. This integrates an RCDT system into the timer and its control unit and entirely eliminates external wiring by using an optical link to program the timer.