relay or 555?

[brentnagel]

summary of my problem...

I want to capture different states of a machine that are determined by one cycle light.

States:
1. light is flashing (roughly 1s ON/OFF) - the machine is in waiting mode
2. light is steady on - machine is in cycle mode

currently the light is connected to a relay so I have the NC/NO poles available.

I have 2 available 12v sources on the machine.

if the light is flashing I need a steady 12v (somehow flatten out the ON/OFF)
if the light is steady I need a steady 12v

I cannot have both signals.

I believe I need a combination of a RC circuit and an XOR circuit but I have very limited experience in design. Should I use relays, a 555, or ???

A rough circuit design would be very helpful.

Thank you,

 

[4pyros]

if the light is flashing I need a steady 12v
if the light is steady I need a steady 12v

So you need steady 12 volts all the time?

 

[ChrisP58]

I'm not quite sure what you need, but I think you're looking for a circuit that can discern between the flashing and non-flashing states.

If so, I would use a "missing pulse detector". Google that phrase. They're easy to make with a 555.

Set the timing to be a little longer than the flash period.

The output of the 555 will be in one state while the input is flashing, and change state shortly after the flashing stops.

 

[brentnagel]

Thanks Chris - that should get me started int he right direction.

4pyros - the flashing and non-flashing states will be separate circuits

 

[brentnagel]

After reviewing a few missing pulse detector examples I'm concerned about how it can tell the difference if the input stays high vs flashing

If the input is flashing pin3 will be high
If the input is steady pin3 will be high

I need to somehow separate those 2 states ??

View attachment 65670

 

[4pyros]

OK so you want two separate outputs.

One on only if the light is steady on and the other on only if the light flashes.

Are these the only two states of the light or is it completely off sometimes?

 

[brentnagel]

Yes, it is completely off at times