The counter


Posted on Feb 7, 2014

The circuit of this device is quite simple: an input circuit filters the signal provided by the antenna to reduce sensibility to other phenomena and protects against over voltages. The four transistors realize a `one-shot` section that is triggered by the input circuit and provides pulses of about 0. 05 seconds to the counter (the 470nF capacitor s


The counter
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ets this time). When the one-shot is triggered it cannot be retriggered for about one second (imposed by the 8 F polarized capacitor) to avoid multiple counts for the same strike. This part is powered by a 6LR61 9V cell and, since the power consumption is lower than 1 A (when no strikes are detected) a single cell will last for some years. The test button allows to check if the battery is still operational: each time it`s pressed the counter should increment and, if hold down, the counter should increment about once per second. The two optocouplers interface the output of the one-shot circuit with the real counter and with the PC. I used a digital 5-digits LCD counter powered by a single LR6 (AA) 1. 5V cell. The power consumption of this counter is about 1. 5 A and the battery life is about one year. This counter also has a reset switch and a piezo speaker that beeps on every operation. Any other counter should work fine (even mechanical ones) but the interface must be modified. The insulation between the counter and the one-shot provided by the optocoupler here is not necessary: I just used an optocoupler to adapt the two different supply voltages (9V and 1. 5V). A transistor and a resistor could work as well. A 6-9V DC counter can be directly connected between the collector of the 2N2904 ant the ground. This circuit is not critical and every semiconductor can be replaced with similar ones. The input circuit uses power...




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