shrtcirkt

Well-known member
Joined
Dec 22, 2001
Messages
328
Reaction score
0
Ok... I am working on adding an Opto Coupler to my pir board, and currently using JoeD's chip. The trigger for the chip is a LOW. What I am wondering is, will the output of the opto coupler pass voltage across the collector/emitter same as relay contacts would? Or will I need a resister on the collector side to ensure enough of a voltage drop to provide the right trigger voltage (low pulse) to the PIC controller?
Man I am rusty at this stuff, but it seems that the internal transistor is only going to turn on with + voltage on the collector, and the emitter tied to - Arch, Tin, Brian.... anyone.... HEEeeeellllpppppp
:)
 

Tinhorn

Well-known member
Joined
Mar 13, 2001
Messages
3,516
Reaction score
0
I assume u're not using either the RS or MS20 PIR,  does your PIR go Low when it senses motion or High? and what is the trigger's output voltage max?

I think you only need the Opto's on the timer output to trip the camera.  

All you need (I think) is either direct connect to the timer (if the trigger is 5v Max  and goes LOW at trigger) or a transistor to take care of the voltage if the sensor voltage is over 5v's

And if the PIR trigger goes from Low to High, a transistor inverter to take care of that problem, which would also take care of the voltage of the trigger....

The transistor may be either a NPN or PNP, depending on what's what.

Awaiting the PIR specs:

Tinhorn
 

shrtcirkt

Well-known member
Joined
Dec 22, 2001
Messages
328
Reaction score
0
Tinhorn,
I'm using an amazon electronics PIR module which has an active high equivelent to the input voltage, which is 5 voltsin this case.
I think you're right, the transister inverter will probably be the best way to trigger JoeD's chip.
Any suggestions on a part #?
 

Brian

Inactive
Joined
Jul 30, 2001
Messages
1,194
Reaction score
0
A 5 volt output to the optos pull in side (which as a symbol looks like a diode) with a 10K resistor in line gives a load current of 300uA or so.  Anything larger than the 10K doesn't seem to work.  I tried 20k and so forth but it was not enough to pull in the opto. You can hook the output side of the opto to the camera direct with no resistors.  Make sure the collector of the output on the opto goes to the "shutter/focus" and the emitter of the opto goes to the common on the camera or it will not work.

Hope this helps.
 

Archilochus

Well-known member
Joined
Mar 27, 2001
Messages
1,285
Reaction score
0
Hi shrtcirkt,
Also remember that at least one camera model (the Fuji 60AF) needs the shutter connections the other way around... collector to "common" and emitter to the 1/2 & full press contacts.
Every other cam I've tried has been the way Brian described - but if you're using a "non-typical" camera you might have to do some experimenting.

Archilochus
 

shrtcirkt

Well-known member
Joined
Dec 22, 2001
Messages
328
Reaction score
0
Thanks Brian & Arch, that answers a couple of questions for me.
One last question remains,
Can the output of the opto be used as relay contacts to supply a negative pulse to the JoeD's chip.
As Tinhorn mentioned, a voltage inverter from my PIR output would probably be the best way to go,
Any suggestions on a suitable Voltage inverter for this ?
Thanks Guys
 

Brian

Inactive
Joined
Jul 30, 2001
Messages
1,194
Reaction score
0
You don't need to use the opto for triggering JoeD's chip.  You need to use an inverter if you have a low to high transistion on the trigger from you sensor.

I will send you my document which has a schematic of the inverter configuration within it.  It consists of a 2N3904 with two 10K resistors.  
 

shrtcirkt

Well-known member
Joined
Dec 22, 2001
Messages
328
Reaction score
0
Thanks Everyone!!
Brian, the docs you sent me are just what I needed, thanks!!
 
Top Bottom