Relay problems with timer!

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halfmoon

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I'm having some problems with my timer unit. I based it on tinhorn's timer pictures. I used a 556 IC. I have a 9 vlt. battery powering the unit.

I believe I have everything covered because if I connect a small speaker to pin nine (which is the output of stage two which triggers the camera) the speaker beeps for 2 - 4 seconds.

My problem is when I connect the output (9) to the 5 vlt. relay with the diod (polarity checked) and the other side of the coil going to a ground the relay stays closed (tripping the camera) for as long as the ground is connected.

PLEASE HELP IF YOU CAN!!!!!
 

Tinhorn

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Halfmoon

I don't have any guesses "YET", on your problem but want to make a few comments:

1.  1st, the reason I used TLC555's is because Radio Shack stocks these
    and they are 10 times more energy efficient than the 556 you used
    (Longer Battery Life)

2.  What does the speaker "Beep" sound like?
    It should only be a "Click" as the Circuit energizes
    then another click as the circuit De-energizes
   2 to 4 seconds later

3.  Since you are connecting the relay to ground, I
    assume you are NOT using the TEST/ARM switch...

4.  I also assume you didn't use any LED's in your circuit

5.  I didn't double check you on the PIN ID of the 556 but
    assume you are correct on Pin 9 being the output

If you can, post or email the schematic you drew-up so I can see what you did.

Also, comment on the above notes, maybe something you say will give a clue as to the problem

Tinhorn





(Edited by Tinhorn at 5:19 pm on April 30, 2001)
 
H

halfmoon

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Thank's for the quick reply!!

I do have one one led which is connected to the output of stage one side of the the 556 which lets me time my time out lenght.

The peizp speaker is from radio shack and it gives a single beep for 2-4 seconds.

I don't have a arm/test switch but I plan on putting one in.

I don't have a schematic of the timer draw-up, but I tried to follow your drawing you posted with the pictures.

Thanks for the info on the 556 timer. I didn't realize it was not as effecient as the 2 555's.

I hope this helps you to help me.

Thanks again.
Kirk
 

Tinhorn

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HalfMoon,

If you have an LED on Stage One and it is on for ? min's and the speaker buzzes for 2 - 4 seconds sounds like it "IS" wired OK ? ? ?

I am wondering if the Relay you are using has N-O and N-C contacts.......if so,  you should be using the COMMON lead and the N-O  (Normally Open)  contacts.......

Nothing you said so far, gave me any CLUES ! ! !  :(

Hmmmmmmm

Tinhorn
 
H

halfmoon

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That's what is so confusing. The timer works fine with the speaker connected. The relay is a N-O relay with the output from stage two powering the speaker and the relay and both grounded.

I think I may go and buy another relay because that seems to be the bad apple in this timer. I have already changed the diode so the relay is the only part of the equation that I have not changed.

Please let me know if you think of anything!

Thanks again
 

Archilochus

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Hi halfmoon, Tinhorn,
Just a note on the 555 / 556 power consumption.  The bipolar 555 / 556 (prefix NE, LM etc) uses lots of power.  The CMOS 555 /556 (prefix TLC, TS, Etc.) use less power.  I think RS does not stock the CMOS 556, but they can be purchased from most catalogs.

If you want serious low power parts, go with the 4047B, 4538B, 74HC221, 74HC123, or 74HC4538.  These parts consume power only while active (when triggering the camera).  OK, they use a very tiny bit of power "at rest", but such a small amount that I can't measure it on my meter.

Archilochus
 

jayber

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Figured I'd post here since it's a recent topic on 555's/timers......

Has anybody tried using the All Electronics CMOS Timer (C1555), Cat. #ICM7555 or CMOS 555 Timer, Cat. #7555?  The first camera having a Radio Shack TLC555 timer worked great while the second with C1555 would take one pic then lock up.  Just wondering if anybody has any insight......
 

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