Showing posts with label wireless. Show all posts
Showing posts with label wireless. Show all posts
Thursday, October 16, 2014
New Wireless Auto Tachometer
Anyone performing their own automobile tune-ups knows how important it is to know your engines speed. With this tachometer, you can measure your engines speed without any connections or annoying timing lights.
Wireless Auto Tachometer Circuit Diagram
- Calibrate the unit as folows:
- Set up this circuit:
- Turn on the Tach and allow a few minutes for temperature stabilization.
- Set S2 to 4 cylinders and adjust R5 for a meter indication of 180 (1800 rpm).
- Set S2 to 6 cylinders and adjust R6 for a meter indication of 120 (1200 rpm).
- Set S2 to 8 cylinders and adjust R7 for a meter indication of 90 (900 rpm).
- To use the Tach, turn it on and let it sit for one minute to allow for temperature stabilization. Extend the antenna, select the right number of cylinders and hold the unit over the engine. If the reading is erratic or the needle jumps around, move the antenna closer to the ignition coil or spark plug wires.
- The unit draws power from the car battery. If it is connected backwards, it will not work, but it wont be damaged.
Sunday, August 17, 2014
Build a 9V Wireless Microphone FM Transmitter
This FM transmitter schema can be used as a wireless microphone, can be received by an ordinary 88- to 108-MHz FM broadcast receiver. For the power supply, this transmitter schema is powered by a 9 V battery. To comply with the radiation limit of FCC rules, keep the antenna length under 12 inches. L1 is 6 turns of #24 wire wound around a pencil or a 1/4″ form, with turns spacing of 1 wire diameter. C6 is a gimmick capacitor which has value about 1 pF.
9V Wireless Microphone FM Transmitter Circuit Diagram
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