It is fun to make a variable space in your small room, but it’s hard to make the actuator to move your wall or room partition. Using analog audio line delay, you can adjust your room virtually. Just turn a knob in your audio set and you can adjust your room size. The circuit described here will make your dream come true, giving a feel that your speaker is located 15 meters behind you, even though your room is actually 3 meters wide. Here is the circuit’s schematic diagram.
Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]