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Need a circuit for this...

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New Member
Hey everyone :D

I am looking for a circuit where I can use a high signal to activate a 1Hz oscillator, then as it is pressed for 3-4 seconds it increases to 10Hz, then perhaps from 8-10seconds it increases to 100Hz. I am making an interface where I need to program various values which can range up to the thousands. I don't want to use a keypad for this, just two arrows for up and down.

Any help would be appreciated, I want to keep the circuitry minimal. I wish there was a chip that did this!



Active Member
You probably need a voltage controlled oscillator(VCO). Search for 566 schematic. Its the simplest IC for building VCO.
For the timing part you can do it using 555 astable oscillator and a decade counter 4017 with 4017's output connected to different voltage dividers and these dividers (for setting up voltage) are OR'ed through diodes and connectd to input of VCO.
The other very simple method is to use a microcontroller for this.
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