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Sly
09-04-2010, 07:23 PM
I have some small "mini" strobes like the ones that you get from wally world around Halloween. Similar to the attached picture. I want to be able to control these using the low voltage signal from a controller so that they will flash once every time the on signal is sent and so I can flash multiple strobes at the same time. The flash is controlled by a bt169d scr. I would like to use some kind of opto to switch the scr so the 300vdc trigger voltage is isolated from the controller.

The problem is the voltage is dc and from what I understand the opto will only work with ac voltage. Looked for some optoisolated scr's, but they all seem to be obsolete and no one has any. So does anyone have and suggestions what I could do to make this work. Thanks.

Sly

David_AVD
09-04-2010, 09:23 PM
I've done something similar before and used a standard MOC3021 opto.

The output side of the opto was in series with a 10K resistor and wired between the anode and gate of the SCR.

There was also a 4.7K resistor between the SCR gate and cathode.

budude
09-04-2010, 09:35 PM
Cool - I've got 3-4 of these myself - sounds like a nice mod!

Sly
09-07-2010, 08:22 PM
I got back to messing around with this and tried what you suggested. It did make the strobe flash, but it flashed at the set rate as long as the opto was turned on.

What I want it to be able to do is flash once when the opto is turned on. Basically if I wanted it to flash five times I would have vixen turn the controller on and off five times. Like a camera flash, it will flash once every time the shutter button is pressed.

If I remove the scr from the strobe and short the anode to the cathode it will flash once and every time you short them it flashes once. If I remove the scr and put the opto between the anode and cathode and turn the controller on it flashes once, but when I turn the controller off and back on again it won't flash unless I remove one of the wires on the output side of the opto and put it back. Any suggestions to make this work. TIA

Sly

David_AVD
09-08-2010, 02:05 AM
You'll have to remove the existing charge resistor I'd say.

If you sketch out the existing circuit, I'll see what I can do.

Sly
09-10-2010, 08:11 PM
I have attached pictures of the top and bottom. Don't know if they will be any help or not. If not I can try to come up with a rough schematic. Let me know if need some other info or pics and I will see what I can do. Thanks.

Sly

David_AVD
09-11-2010, 01:32 AM
It's a bit hard to say from the pictures. If you draw (or find) the schematic, I'll work something out for you.

budude
10-16-2010, 11:14 PM
Hey Sly - Did you ever get a schematic drawn out? If not, I will attempt one from mine (I have 3). I'd like to sneak this in for Halloween if possible.

marble42
10-17-2010, 09:07 AM
hi I did something like this for my camera flashes i got out of through aways
soldered the flash button together so it is constant on,used a pcb 24 volt relay
from my ren 24lv as the input to the switch so every vixen sends a signal to the relay it will flash once.I get the relays from Skycraft for one dollar each so it worth the time..

Sly
10-17-2010, 06:54 PM
I didn't forget about this. Just got put to the side. Have a schematic started and will try to finish by tomorrow.

Sly

budude
10-17-2010, 07:46 PM
I didn't forget about this. Just got put to the side. Have a schematic started and will try to finish by tomorrow.

Sly

That's great. Just to compare, mine are Heshan Lide Mini-Strobe Model MSL-001 Item# 17100.

Sly
10-19-2010, 06:00 PM
Here is the schematic. I hope I got it right. If you have any questions about specific components or values let me know. It is a Heshan Lide Mini-Strobe Model MSL-001.

Sly

7795

7819

David_AVD
10-20-2010, 04:35 PM
Sorry, the schematics are not correct. There are parts that lead nowhere, etc. Reverse engineering a PCB sure is tricky!

Sly
10-21-2010, 01:10 AM
I updated the post above. There was a connection I missed on R8. R12 has no connection if you look at the board. In the picture of the bottom it shows where R12 connects on one end to R4 and the other end goes to a pad on the bottom that is not connected to anything else. I am not sure why that resistor is even there. The two connections of the right on top and in the middle are the power connections. The three connections on the left are the positive, negative, and trigger that go to the strobe tube. So that should take care on any missing connections. The layout probably isn't the best, but this is the first time I tried making a schematic for a pcb.

Sly

David_AVD
10-21-2010, 04:39 PM
What are are controls R5 & R9 labelled as? One would be rate, the other I'm not sure.

budude
10-21-2010, 04:59 PM
What are are controls R5 & R9 labelled as? One would be rate, the other I'm not sure.

It's not adjustable from outside the box (it's the trimpot on the PCB) so it might be a baseline setting at the factory or something (not sure why a pot vs fixed resistor though).

dirknerkle
10-21-2010, 05:03 PM
It's not adjustable from outside the box (it's the trimpot on the PCB) so it might be a baseline setting at the factory or something (not sure why a pot vs fixed resistor though).

Probably for variances in the strobe tube.

David_AVD
10-22-2010, 04:55 AM
I'd try by removing the DIAC and using the output side of the MOC3021 in place of it. Don't forget the series resistor in series with the LED of the opto.