Timer Problems

smendy

Member
Joined
Jul 21, 2001
Messages
8
Reaction score
0
I am new to this Forum but have been visiting the site for a few months.  I built my first deer cam, without a timer, and put it in the woods last week.  I could not have done it without the help of this site!  It is working great, but I am trying to build Tinhorn's timer to add to the next one I build.  I have put together the board, but when I test it, the LED will light, but it does not turn off after 2 sec.  Pin 3 of IC1 starts at 6.2V, but after two min it does not reach 0V, it only drops to 2.5V.  I am using a 680ohm resistor for R7 & R8 since I will have a 12V powering the unit.  

Anyone know what could be causing the problem?  
Thanks for any help.

Smendy
 

Tinhorn

Well-known member
Joined
Mar 13, 2001
Messages
3,516
Reaction score
0
Smendy

Somehow volts are getting to Pin 3 that shouldn't be there (after it times out)  

It could be a bad TLC555 but I don't think I have ever seen one blown yet, check the Lead ID on the transistor (C,B,E) and other wiring on pin 3....

Tinhorn

(Edited by Tinhorn at 9:54 am on July 23, 2001)
 

warrendsga

Member
Joined
Jul 12, 2001
Messages
11
Reaction score
0
I hate to say it but I blew several 555 timers (or they were just bad).  All of them came from radio shack.  I built the 555 test circuit shown on the web (search 555 tutorials) and ran them through the test.  It indicated that 2 out of 5 timers were malfunctioning.  It could be that when soldering/desoldering I let the timers get too much heat and it ruined them..who knows!
 

dharter

Well-known member
Joined
Jul 7, 2001
Messages
83
Reaction score
0
Static electricity may have damaged the chips if they are CMOS.
 

Jaggermax

Inactive
Joined
Apr 6, 2001
Messages
505
Reaction score
0
As Dharter mentioned, the CMOS chips are HIGHLY susceptable to static.  I have zapped CMOS 555 timers before simply by turning in my chair, especially the Radio Shack brand.  

If you can, socket the 555 chip in your circuit first and use a non CMOS 555 timer, just for your testing.  Once you get the circuit working, replace the non CMOS with a CMOS 555 timer, but be sure to touch a ground to discharge yourself before you touch the CMOS timer.  I prefer CMOS because they consume much less power.  
 

smendy

Member
Joined
Jul 21, 2001
Messages
8
Reaction score
0
Finally...the timer is working.  Turns out the 555 timers were OK, I had the transistor wired in the board wrong.  Second camera should be going in the woods soon.  So far the first camera is only good for taking pictures of coon.
 

BowDoc

Well-known member
Joined
Jun 30, 2001
Messages
78
Reaction score
0
someone posted a picture of how the timer is connected to the sensor can someone repost it
 

Iowabowhunter

New member
Joined
Feb 24, 2002
Messages
4
Reaction score
0
I just wanted to drop some of you a line to help me out with a problem I have, in order for my reed relay to work I needed to wire it to my Led, or what use to be my speaker on my Radio Shack 49-425, meaning that my pin #2 of my "big IC" is not working. So how do I make the timer work?  


Can someone also send me a simple design of a good timer with a 1 min delay?
lopezfam@starband.net if you could please...Thank you!!!
 

Iowabowhunter

New member
Joined
Feb 24, 2002
Messages
4
Reaction score
0
After doing some homework, I figured that Marty's Timer will work, but to get the delay I want I will have to go with a larger Cap....and smaller resis....

I hope this works!!
 

Tinhorn

Well-known member
Joined
Mar 13, 2001
Messages
3,516
Reaction score
0
You really ought to buy one of JoeD or Brian's 8 pin ICs and build a timer using them.  Neither is all that hard to build and it'll do a better job.......

Tinhorn
 
Top Bottom