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A String of Resonators

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EltonBrasil

Junior Member level 3
Hi Everyone,

If I had a string of resonators (let's say 24), on a parallel circuit with a switch before each resonator, would we know a robust circuit in which could determine which of the switches were closed? Any one or any combination, or even all may be switched on. Would each resonator have to be at different frequency? If 24 is too many, what is reasonable?

Assuming current goes through the wire (regardless whether AC or DC)...
Install a sense resistor inline, and detect voltage across the resistor.

EltonBrasil

EltonBrasil

Points: 2
Hi,

The schematic is not clear to me. Please draw a sketch.

A resonator is a passive device. It needs at least an inverter to do something. And the inverter needs a power supply.
To detect different "operation modes" (closed switches) you need to get different electrical values. Maybe you think about different frequencies.

Now you may have 24 different frequencies (built with 24 resonators and 24 inverters), one for each switch. Then how do you combine the "frequency signal"? Do you want a single wire signal?
Or you have one oscillator generating different frequencies for different switch states. But when you want to detect the states of 24 states at once, maybe with different frequencies. Then you have 2^24 = about 16 million different combinations to differ. 16 million different frequencies?

*****
Useful solutions:
With frequecies: do it similar to the DTMF technique like used in telephones
With a microcontroller: use a matrix of 8x4 keys. For lowest uC pin count additionally use a "1 of 8 decoder" and use 6 port pins.
Or use a dedicated keyboard controller
There are many other possible solutions..

Klaus

EltonBrasil

EltonBrasil

Points: 2
Not even the circuit purpose is clear. Resonators can be used in oscillators or filters.

Hi,

The schematic is not clear to me. Please draw a sketch.

A resonator is a passive device. It needs at least an inverter to do something. And the inverter needs a power supply.
To detect different "operation modes" (closed switches) you need to get different electrical values. Maybe you think about different frequencies.

Now you may have 24 different frequencies (built with 24 resonators and 24 inverters), one for each switch. Then how do you combine the "frequency signal"? Do you want a single wire signal?
Or you have one oscillator generating different frequencies for different switch states. But when you want to detect the states of 24 states at once, maybe with different frequencies. Then you have 2^24 = about 16 million different combinations to differ. 16 million different frequencies?

*****
Useful solutions:
With frequecies: do it similar to the DTMF technique like used in telephones
With a microcontroller: use a matrix of 8x4 keys. For lowest uC pin count additionally use a "1 of 8 decoder" and use 6 port pins.
Or use a dedicated keyboard controller
There are many other possible solutions..

Klaus
Klaus -- thank you very much for the clarification. I was thinking about sweeping the frequency range on the line and looking at the frequencies that resonate as the signal should build at those frequencies to some detectable threshold. Since I design the resonators, I know which frequencies to hit. However, I wonder if I could distinguish 536 frequencies using any technique.

Hi,

Why 536 frequencies for just 24 switches?

Still the schematic is not clear.

Klaus

A radio or tv is exposed to myriad frequencies coming to it from the antenna, yet it extracts only one of those signals.

Likewise photons at myriad frequencies travel through a fiberglass cable, impacting a detector, yet it responds only to a particular frequency.

Just add a second pole to every switch to indicate if its on or off.
Multiplex the switches 6x4 and you can scan all 24 switches using only 11 connecting wires.

this project might help you, he has used string of resonator in a parallel circuit similar to you problem. check this out.

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