![]() This networks works like the third oscillator. In IC1c, the outputs of the two oscillators are merged to generate a third signal frequency, which is applied to the bridged inputs of IC1d. The second oscillator also operates in the same way as the first, except that its output switches at a different frequency, that is regulated by C3, R2, and the value of R8 (a 470K potentiometer which functions as the MODULATION control for the circuit). The second oscillator output which is configured around IC1b feeds the other input to IC1c. That series of events continues indefinitely for long as no light is available over the LDR R10 surface.ĭuring this time, the output of IC1a proceeds down the second channel and is fed to one of the inputs of a gating circuit (configured around IC1c). This low is fed back to IC1a's inputs, enabling its output to become high yet again. This high is sent back into the inputs of IC1a (causing C4 to charge), driving its output low yet again. The IC1a output is fed back to its input through one channel, causing its output to flip high. The low output of IC1a is split into a couple of channels. As a result, the output of IC1a is forced to be low.ĭue to the impact of LDR R10, the output of IC1a stays low so long as the power is switched off or is at a reduced level, just until the inputs of IC1a are dragged high through some other external source. This causes the voltage provided to the inputs of IC1a to increase. The resistance across R8 begins to drop as the light intensity measured by R10 decreases. The LDR R10 detects ambient illumination and has a resistance of many mega ohms in absolute darkness and a maximum resistance of about 200 ohms in full light. When the light hitting R10's LDR surface decreases to the required level, the first oscillator, along with with R10, triggers ON the circuit. The light intensity which causes the triggering to occur is determined by potentiometer R9 (SENSITIVITY). It's worth noting that the circuit is essentially a single 4093 CMOS quad two-input NAND Schmitt trigger (IC1) arranged as 3 oscillators linked sequentially, each influencing the functioning of the one before it. Circuit DescriptionĪ schematic view of the Electronic Cricket circuit is shown below. Basic Working Conceptīasically, the Electronic Cricket is a light-sensitive device which switches on in low-light conditions or complete darkness, but switches off as soon as subjected to full room light.Īpart from the possibility of the circuit being used in an inoffensive prank, the design can be educational since it shows how just a single 4093 IC could be used to create three electronic oscillators (two of which contribute to making the chirp sound, and the third of which works like a timer to provide a slight delay between chirps). But as soon as the lights are turned on, there is complete quietness… no sound at all. When your friend has had enough, he or she gets up to look for the tiny demon. The chirping proceeds even while your friend stomps the floor or flings a shoe in the location of the sounds. Our cricket bug also has no idea when to stop. This little bug starts chirping, chirping, chirping as soon as the home lights are turned off (say at bedtime). But before you leave your friends house, you hide a nasty little circuit somewhere in the house, that simulates a Cricket noise. ApplicationĪssume you've just returned from an evening spent at a friend's home. This is done using a set of oscillators configured to simulate the cricket's chirping sound. An electronic cricket sound generator is a device which generates a sound exactly similar to a real cricket insect.
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