Here's a old favourite, using simple momentary pushbuttons.

The main disadvantage is that it has to be reset between selections.
The radio PB circuit doesn't.

 

The signal needs to go between Vcc and ground (a CMOS input can never be left open/floating).
If you want to use a SPST push-button switch that switches to Vcc, then connect each input to ground with a 10kΩ resistor.

Ok I got momentary push button switches with only NO contacts. For this application I need a push button switch with both NC and NO contacts, NC connecting inputs to ground and when the push button is pressed the NO connects the input to Vcc momentarily and then when it is released the input is connected to ground again through NC contacts.

Or if I am using only NO contacts, I connect each input to ground through a 10kOhm resistor.

 

The main disadvantage is that it has to be reset between selections.
The radio PB circuit doesn't.

I believe not. The selected line is high, and the next PB pulls the control low, enabling the clock.

 

I believe not. The selected line is high, and the next PB pulls the control low, enabling the clock.

Looks pretty simple... so with 4017 and 4093 NAND gate IC and push buttons with resistors and capacitors this can be done.

Radio PB circuit also uses two ICs I will try this Radio PB one first see how it goes.

Thanks.

 

I believe not. The selected line is high, and the next PB pulls the control low, enabling the clock.

That seems correct.
I missed that connection.

 

If you wanted to do the selection with momentary push-buttons, then a "radio-button" circuit would work for that.

Crutschow,

I got the rotary switches and they get too messy, every time I should turn them all the way to the end and all the way back and with every frequent usage they get worn out pretty quickly. So you are right, thanks for the circuits in post #14.

In this circuit using OR and XOR gates for interlocking the 555 timer outputs for making one signal output at a time and signal output is isolated from the other 555s. Since pulsed signals are used at ranges of 0.1 to 42 Hz, what is the value of capacitors need to be used at Vcc to ground. Do pull down resistors have to be used. They are not present in this drawing so wanted to confirm.

 

what is the value of capacitors need to be used at Vcc to ground. Do pull down resistors have to be used. They are not present in this drawing so wanted to confirm.

A 100nF ceramic is a typical IC decoupling capacitor to ground.
Yes, the circuit needs 10kΩ resistors to ground at each input if a SPST PB to Vcc is used.

 

A 100nF ceramic is a typical IC decoupling capacitor to ground.
Yes, the circuit needs 10kΩ resistors to ground at each input if a SPST PB to Vcc is used.

Ok. I will use a 100nF capacitor.

I plan to use push buttons with nc and no contacts so I wouldnt be needing the 10kOhm resistors.

 

Below is the LTspice sim of the basic PB Radio latch circuit shown in post #19:
It does have the advantage of not requiring pull-up/down resistors if a SPST NO push-button is used.

I changed the oscillator inhibit circuit to stop the oscillator between button presses, as it doesn't need to oscillate during that time, thus reducing quiescent circuit operating current to just the leakage current of the IC.
I also significantly increased the frequency of the oscillator to minimize the length of the observed normal one clock-period output glitch (about 8µs here).

 

plan to use push buttons with nc and no contacts so I wouldnt be needing the 10kOhm resistors.

That would be SPDT contacts, right?

 

That would be SPDT contacts, right?

This switch here

https://roboticsdna.in/product/7mmx7mm-tactile-push-button-switch-no-locking-5-pcs-white/



Thats a momentary push button switch with 6 pin connections has normally open (no) and normally closed (nc) contacts. NC I will connect inputs to ground and NO I will connect input to Vcc so when it is pressed it will release the contact from ground and touch Vcc and when released it connects to ground again.

 

This switch here

That should work.

 

That should work.

This is the circuit I will be using for switch debouncing at every PB switch for a Vcc of 5 Volts I hope the resistor and capacitor values are correct. Let me know if I need to change. Thanks.

 

This is the circuit I will be using for switch debouncing at every PB switch

You don't need switch debouncing for the circuit you are using, as once the switch makes contact, further bounce connections make no difference at the output.

 

You don't need switch debouncing for the circuit you are using, as once the switch makes contact, further bounce connections make no difference at the output.

Great, Thank you!

 

In this circuit using OR and XOR gates

Those are OR and NOR gates, not XOR.

 

You do realize that the circuit in post #26 will require more ICs for controlling 7 outputs (total of 6 ICs), than some of the other posted circuits which only require 2(?).

 

You do realize that the circuit in post #26 will require more ICs for controlling 7 outputs (total of 6 ICs), than some of the other posted circuits which only require 2(?).

Yes I understood that. Four of the XOR ICs and two of the OR ICs.

 

Four of the XOR ICs

That's NOR.

 

Great! That's a good solution. A rotary switch for selection. I didn't think of that and I was thinking of so many other ways to provide interlock. This is the simplest solution.

Thanks a lot, nsaspook.

If you use rotary switch, the selection is sequential. You cannot randomly select any input because of the construction of the switch. You need to wire a push button in series to inject the input when the desired channel had been selected.