JoeD's Timer Details

Tinhorn

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I finally got around to bread-boarding JoeD's Two Stage Timer and boys, he's got something here.  It works like a Charm.

NOTEs
1.  The Timer Output resets, even if the trigger lasts longer than the Time Delay
2.  A Negative "Pulse" thru a .0047 capacitor will trigger the Timer
3.  Output Pulse Length, JoeD states 4.5 seconds, I "Counted" about 6 seconds
4.  Default Delay at Power Up is 15 seconds with my Timer (The Shortest Delay Mode)
5.  Delay Mode Momentary Switch is the one connected to Pin 7 and the corresponding LED connected to Pin 2
6.  Counter Momentary Switch is Connected to Pin 6 and the corresponding LED is connected to Pin 3
7.  Reset Counter to Zero by Powering OFF the Timer:  
8.  Measured Current:  1 ma when Time Delay is in progress and .1 in the Wait (or Idle) State
9.  Specs found on Internet states each output pin can sink 25ma's

Referencing Note 2
I connected the Output of an MS20 directly to the Trigger Input (Pin 4) but found it wouldn't work, so I tried using a .0047 cap (shorted by a 1m bleedoff resistor) and discovered it worked fine this way.


Referencing Note 7
This means if you want to retain the Count, it must <not> be turned off.  Since the Wait-State Current is so small, a power switch could be used only on the PIR, which draws quite a bit of power compared the the Timer.  The Batteries would last a long time this way.

Referencing Note 9
I measured the current of 2 of RS's 5v Reed Relays and found one had 23.9ma's and the other 23.5ma's (at 6volts)   This agrees with Ohms Law which is  volts/resistance     6v / 250 ohms = 24 ma's        5v / 250 = 20ma's (the rated current noted on the package)  This current is so close to the Timers Rated Current, I decided to use a Relay Driver Transistor, as can be seen in the Schematic below.  This Relay Driver may not be necessary but I wanted the Timer to "Coast" in the Summer month's heat.  

NOTE:  if you use JoeD's suggestion of 3 AA's (4.5 volts) then the relay current would only be  4.5 / 250 = 18 ma's, well within reason, and no transistor driver would be needed.

I measured the LED/Resistor combo as <15ma's and thought transistor drivers were not needed for them.  RS sells a Low Current LED but I have an abundance of regular LED's and use them

Power Source
The MS20 has an internal 5v regulator that I tapped off of to power the Timer (collector of Q1)  Since the MS20 can be run off of 6 to 24vdc, this means this PIR will work off about any battery.  The LED limiting resistors and relay would be the only thing needing changing if a higher voltage battery is desired.  The reason I didnot power the LED's and relays off the PIR's 5v supply is because I don't know what the internal 5v regulator's power rating is.  I doubt it could provide the 20ma's needed tho.

Suggestion
I'm thinking the counter could be dispensed with and a Refresh Pulse be provided at that output pin (1/4 sec pulse every 7 min's)

Basic Time Delay
If you <ONLY> want a delay between pixs, this timer makes it easy.  At power up it defaults to the shortest delay, 15 seconds in one version and 1 minute in the other.  All you'd have to do is connect the PIR trigger (thru a cap), a Reed Relay to the Camera Shutter, and the battery (3 AA's)  You'd be in business

This Schematic is what I built:
I added a TEST LED, it will test the entire circuit except the Relay/Camera and you can flip it to de-activate the Cam if desired

 

Archilochus

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Hi Tinhorn,
Thanks for the details - been thinkin' of trying one of these timers.

Does the flash in any of your cameras regharge fast enough to take advantage of the 5 second double picture mode??
None of mine would, even with new batts.

Happy holidays,
Archilochus
 

Tinhorn

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Hi Arch, Happy Holidays.........

I had my doubts too and bet some will, some won't, probably depending on how long the cam's been dormant.  

The camera I used did work tho, but I had fired it a few times testing the timer in normal operation before trying the Double Pix Mode.

I had to smile tho, when it did work!

Tinhorn
 

shrtcirkt

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TinHorn,
thanks for the work here, and also the reply onmy other post. I do not fully understand what purpose of the cap is going to pin 4 can you explain the theory behind this for me?
About the dual mode... I tested mine with 2 of the OWL PF's I have and it worked great on both of them. Even after sitting for over 2 hours I got a flash on the first trigger and the second. Dunno if I got a couple of good cams or not but I'm glad they work.
Also, you asked about the power requirementsof the PIR i am using, it operates at 4-12VDC and 400ìA @ 5vdc. Output is listed as an active high of .5 sec.
Does this help any?
Anyway... have a great holiday and thanks again.
 

Eagle Eye

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Thanks for this info Tinhorn. I bought two of joeD's chips a while back and really like them.
My PF works fine in the double picture mode, on the bench. Dont know how it will work after setting a few days. So I stuck an old Owl in for field testing.
Im hoping to get at least 3 months out of my Versa - Pak battery which shows 4.5v fully charged, although its listed as 3.6v. (I'm using the extended life model)
My X10 test sensor batteries (2-AAA's) still show a full charge after two months.
Think this is to much to ask?
 

Tinhorn

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Howdy ShrtCirkt,  Merry Christmas

I just reread your posts for about the 3rd time and you did some real good tests trying to isolate the problem, breaking down the circuit into segments, bypassing, etc.  I can tell you've had some experience in troubleshooting somewhere.

You mentioned in the PIR specs that it has an "Active High" on it's output.   This is probably the problem in connecting directly to Pin 4 of the timer, Pin 4 needs to see a Negative pulse (LOW) to trigger.

(HIGH means Power Supply Voltage and LOW means at or near Zero Volts)

This Active High tells me the relay coil "other" end would need to be connected to ground (batt (-)), which you did, but I still don't understand how that grounding contact did not trigger the timer?????? unless for some reason there was not enough power to Close the contacts!

Well, to get to your question on the Cap between the PIR and Timer.  I think the DC volts on the PIR output was confusing Pin 4 somehow, so placing the cap between the 2 blocked the DC Voltages (from each other)  The cap allowed the "Changing" voltage from the PIR's output to get thru, as a spike, but enough to trigger Pin 4.  

Sometimes a cap will hold a charge long enough so it won't allow this Pulse to get thru so the 1M resistor was added to bleed off this charge.  1M is a very high resistance and altho some DC would leak thur, it isn't enough to cause any problems......

Eagle Eye:  Happy Holidays!

That X10 PIR is perfect with JoeD's Timer, I bet you will get MONTHS of service off those battery's.  Thats a good idea using that Versa-Pack battery on the Timer, good thinkin'

My Next step is to get an energy efficient PIR.  The MS20 uses 1.7 ma's at 6volts.  4 AA's should last about a month and a half.  Man, I used to think 1.7 ma's was LOW......

See Ya!

Tinhorn

The RS isn't to bad and I see by the Schematics that it has a 5 volt regulator.  It could be used to Power JoeD's timer (I guess)
 

shrtcirkt

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Hi TinHorn, Merry Christmas to you and yours as well :)

Well you are right, I have had some troubleshooting experience, except not to component leven in about 15 years. I'm afraid I know enough to get myself into trouble.... but not out.
I am gonna hit RS this week and pick up a couple of caps and resistors to try. Did you use a polarized cap? Would it make a difference?
The thing that boggles me about this the most is that if I isolate the individual circuits running the PIR off of one battery and the timer off of another, using the contacts from the relay off of the PIR to bring pin 4 low it works perfectly. but as soon as I share the power source I get into trouble. I guess it is what we used to call FM when I was in school...
'Freaking magic' LOL.
I did move my connections points for the power source around and it did not seem to make much difference.
Well, i guess the challenge is at least half the fun of all this... I should have stayed in the field instead of riding a desk for the last _ _ years.LOL
 

Brian

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Tinhorn,

Is the MS20 trigger high to low or low to high and is this a 0 to 5Volt signal.

The RS sensor is low to high 0 to 5Volts but I haven't checked the MS20 yet.

Also, is the 1/4 second refresh all it takes.  I have designed a half.  This may be too much so I wanted to make sure.

Thanks,

Brian
 

Tinhorn

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Brian,

MS20
The "Unmodified" MS20 uses the Raw Supply Voltage to trigger a Relay Coil with a Driver Transistor.  Most guys are replacing the original 24VDC relay with a 5v, 9v, or 12v relay.

I only use 6v's to power my units and remove the relay (and Protective Diode) and install a 10K resistor where the Coil terminals were.  This makes the "Wait" State of the PIR Output 6volts (Batt (+) volts) which goes LOW at trigger......

I don't think the MS20 could be powered by anything less than 6volts because of the internal 5v regulator voltage requirements.  This regulated voltage only goes to the Comparator IC and I tapped into it to run JoeD's Timer.

Note:  my comment about powering "off" the PIR to conserve battery's (Note #7 and Reference #7) won't work will it, the Timer would lose power!

Refresh Pulse
The Refresh Pulse connects to the OWL PF's "Half Press".  When the Half-Press event occurs, the Flash Circuit gets refreshed, then in about 1 second, the Red-Eye-Reduction Light comes on

Since the Camera's circuitry may vary, the 1/4 second seems to be a good choice for insurance that the Redeye Reduction Circuit don't get activated by the Refresh Pulse.  

The 1/4 sec has worked well on the 3 cams I installed it on;  the time of 1/4 sec every 7 min's came from Archy's findings in cold weather....

Tinhorn
 

Brian

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Tinhorn,

Yeah I don't think it will.

The microchips can't handle large voltages on their pins so how about a transistor circuit like we told another guy to use where the five volt regulator on the MS20 supplied the voltage to the chip and the voltage at the collector of the transistor.  We could turn on the transistor with the larger voltage say 24 volts and down at the base and use the collector to drop the voltage to the trigger.  This would give a high to low transition to the JoeD's timer of 5 to somewhere near 0 volts no matter what the supply voltage to the MS20.  All we would have to figure out would be the different resistor values at the base and collector that would give us the least amount of current draw while triggered.  This circuit would not draw any current unless tripped.

Is the chip number on JoeD's timer a 12C671 or 12C672.  Just curious.

Refresh Pulse:
Thanks I will bump it down to a 1/4 second.

Also , does the MS20 have a daylight/dark circuit built in that gives a 0 to 5 volt signal?

Brian

(Edited by Brian at 1:11 pm on Dec. 26, 2001)
 

Tinhorn

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Brian,

JoeD's Timer is a PIC 12CE674

Timer Trigger "Overvoltage" Protection:
I think we could just stick in a 5v Zener on Trigger (Pin 4) and to Ground, to clip any over-voltage triggers.  Referring to my Schematic posted here, we could leave the R1/C1 configuation and place the Zener Kathode on the junction of C1/R1 and the Trigger Pin with the Anode connected to Ground.

I took a look at cutting a trace to the Relay Coil replacement resistor (the 10K I used) and jumpering the 5v reg over to it, it's congested in that area, the only way would be to leave the 10K lead lifted and jumper to it from the 5v regulator.

I think the Zener Clamp mentioned above would be the best bet and would work on any PIR too.

Using a Relay would also solve the problem, grounding one contact and the other go to Timer Trigger Pin.  Most of the guys are doing this now anyway.

MS20 Light Sensor
The MS20 has a Mode Switch to energize the Light Sensor.  On TEST, the Light Sensor is bypassed and the PIR will trigger for 4 seconds, regardless of light condtions.

On AUTO, the PIR won't trigger during daylight hours (keeps the FloodLight OFF), at nighttime, it triggers and stays triggered for about 1.5 mins or so, keeping the Flood Light ON.

I investigated the Light Sensor circuit and don't see how the feature could be used on the MS20 without some work because of lack of sensitivity (poor design in this area maybe)  Even when I shined a desklamp into the sensor it triggered sometimes, at least on this <test> MS20.....

A variable resistor could be installed for 'finetuning' tho

But
What I do is "remove" the PhotoResistor which automatically adds a <Feature> for those cams over bait.

Since light don't matter  when the Light Sensor is removed, it will trigger when motion is sensed and take a pix but won't retrigger again untill all movement stops for 1.5 mins.  If movement is detected before the 1.5 min delay is up, the MS20 resets the 1.5 min time and starts over But DOES NOT TAKE ANOTHER PIX........

The same animal won't keep tripping the cam, ripping off a whole roll of film......

Tinhorn
 

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