electronic latch

[bendyck]

:?:
I built a 8 shaft monitor (missing pulse detector)
4 dual timers, 1 - 8 input Nand gate,
& a 555 timer that operates relay.
When all is running 8 diods are lit up.
If one of the 8 shafts slow down & stop, the one diods flickers
& go out, then the 555 timer opens up the relay
then every thing including the monitor goes dead.
What I would like is some kind of latch??
to tell me which shaft was the problem?
Ben

 

[ljcox]

What you need is an 8 bit latch (or two 4 bit ones) so that when the LED "flickers" the latch stores the state of the 8 shafts so you can see which one failed.

Alternatively, you could use a parallel in parallel out shift register. Or make one up from D type Flip Flops.

Without knowing more detail of your circuit, that's all I can suggest. If you post the circuit, we will be able to help further.

 

[bendyck]

:?:
I built a 8 shaft monitor (missing pulse detector)
4 dual timers, 1 - 8 input Nand gate,
& a 555 timer that operates relay.
When all is running 8 diods are lit up.
If one of the 8 shafts slow down & stop, the one diods flickers
& go out, then the 555 timer opens up the relay
then every thing including the monitor goes dead.
What I would like is some kind of latch??
to tell me which shaft was the problem?
Ben

bb

 

[ljcox]

Yes, I read all of that before and made a suggestion as to how you can achieve what you want.

But I can't help any further unless you post your circuit.

Len

 

[bendyck]

:?:
I built a 8 shaft monitor (missing pulse detector)
4 dual timers, 1 - 8 input Nand gate,
& a 555 timer that operates relay.
When all is running 8 diods are lit up.
If one of the 8 shafts slow down & stop, the one diods flickers
& go out, then the 555 timer opens up the relay
then every thing including the monitor goes dead.
What I would like is some kind of latch??
to tell me which shaft was the problem?
Ben

Because my monitor goes dead when the relay opens,
I was thinking of a mechanical latch. (press to reset)
Is there such a thing??
All timers can source or sink 200 ma
Ben[/u][/i][/b]

 

[bendyck]

Yes, I read all of that before and made a suggestion as to how you can achieve what you want.

But I can't help any further unless you post your circuit.

Len

Sorry I don't know how to send a schematic. Ben

 

[ljcox]

Yes, I read all of that before and made a suggestion as to how you can achieve what you want.

But I can't help any further unless you post your circuit.

Len

Sorry I don't know how to send a schematic. Ben

I do my drawings in PowerPoint. Save them as .ppt and then when ready to submit, do a "Save as" and scroll down the "save as type" menu until I find the GIF Graphics Interchange Format (*.gif) option. This saves it as a .gif. You then do a post as I am doing now and click on the "Add an Attachment" button. The instructions are above the button.

If you look at my profile and then click on the "Find all posts by ljcox" you will see some examples of drawings I have done.

Alternatively, you could do it on paper and then either scan it or take a photo with a digital camera and enter it as a .jpg file.

As for a mechanical latch, you could use relays, but it would be cumbersome. If you can post your circuit, I will be able to help you with an electronic one.

Len

 

[bendyck]

I'm trying to attach a rough schematic.
Ben

 

[ljcox]

Ben,
Attached is a suggestion.

I have assumed that the 555 is used as a relay driver rather than a timer. Is this true?

If you wish, you could connect a Reset button to the Cl pins of the D Types.

Len