This circuit can use a pendulum sensor. We found this configuration in a 1994 publication. The components used are common and the timing is given by the capacitor C1 which can be changed.
This series LED circuit was found in the February 1992 issue of Radio Electronics magazine. The...
We found this circuit in the Linear Applications Handbook by National Semiconductor. The circuit uses...
The noise comes from the PN junction of a common silicon diode. Since no gain is given by the...