process timer

2-10 - elektor february 1981 process-timer J. Meyer Electronically, the process timer is not at all exceptional and uses only a hand- ful of readily available CMOS chips. - However, the method in which the parts have been put to use is novel. The pro- cess timer "communicates" its activities by means of a row of LEDs in conjunc- tion with a small process card (see photo 1). Pressing the start button will cause the first LED to light. After 30 seconds this will "jump" to the second LED, a further interval of 30 seconds will cause the third LED to light and so on down the entire row of LEDs. A "process" card, on which the various process time periods are cali- brated in 30 second steps, is placed along the LED row. The lighted LED will now indicate on the card how far the process has progressed. If the pro- cess is to be temporarily halted, the interval switch can be operated and the timer will stop and await further instructions. Take a practical example. It is required to develo...