Hi,

I'm trying to build an SSR circuit to operate 8 camcorders with a single remote. I was considering
mechanical reed relays, but since I wanted to keep it simple, (no external psu, etc) I opted for AQY212EH opto mos relays since I thought that the original led current is enough for the relay and a single low intensity led.
Everything else is sorted but the relays don't seem to work properly.

I'm using an existing leds current as the control current/voltage for the "control" -side of the relay.
I cut the original leds common negative/gnd to make it go through my circuit.
After the relay the control current goes into another led in series (to visualize what channel I'm on), and back to the original negative/gnd.
The remote signal ~5-8VDC/?mA is going through the "load" -side of the relay. It's a LANC signal (8bit @ ~9600bit/s).

When I tried to control remote without the relays, (by connecting and disconnecting the wire by hand) it worked.
but with the relays the remote doesn't work.

When I use a multimeter to try and measure if the "load" -side is conducting, I hear a buzz instead of the constant beep.
I was thinking of trying to make the pulse into a constant with a capacitor, but it seems to only charge up and quits conducting afterwards.

How to get the relay to continuously conduct instead of pulsating? Is there too little current from the control source?
But the led that is in series is lit up just fine?

I thought this would be easier, but that's what you get for not fiddling around with electronics more often. :/

 

Do you have an Oscope? Likely, the LEDs you tapped into are multiplexed at a rate above your eye's flicker fusion...

 

Do you have an Oscope? Likely, the LEDs you tapped into are multiplexed at a rate above your eye's flicker fusion...

I'd need to test that old junkpile out. Yes I guess they are multiplexed. Would a capacitor not fix this?

Any good hints on how to execute this?

We use a controller to control the camera mounts and would like to get the remote functions all into one. It would be great to have just the channels (1-8) to worry about. Thats why we thought we could use the leds as a "control" for the relays...

The box itself is quite neat Hack'N'Slash!

 

Uh oh, apparently I'd want to bypass the PWM for this IC that the leds go through? SN74LS145

The leds are organized into two rows of 8leds, first row has a common on pin1 of that IC, second row has a common on pin2... we need a constant unmodulated current from the first eight. But will this even be possible or will it mess up the ability to choose wich led 1-8 is on?

Any hints on how to do this easier would be more than welcome
Sorry for being a n00b..

 

Err, I think I might have found a solution.

Would it help if I control a relay with the multiplexed signal but on the load side I put +9V + cap + resistor.

Then run that into second relays control side and put the remote signal into that second relays load side?

 

Hi,

I've got this far. I've added +9V (actual psu measures 12.35V) and a cap + some resistors. I'm using ancient but good ewb 5.1
Any help would be appreciated. It would be nice to get "relay 1 load buzz" to actually simulate something pulsing so that the cap
would work as intended or would it even then work? Does this schematic look sane or does it need changes?


Thanks!

 

I've replaced the Relay 1 load buzz with a voltage controlled square wave oscillator, but I'm unable to get the
"relay 2 cleaned" led to stay on continuously. tried to vary the resistor values and the cap value. Also tried with two caps... :/

 

Oh, dumb old me. Should a normal low-pass filter work?
Removing R3 and moving the cap there, maybe 2.2uF and bumping R2 up to 2.2kohm should do the trick?

 

For some reason it doesn't work. I measured the pulse frequency wih a true rms multimeter, it's 143Hz.
I used the tools:
http://sim.okawa-denshi.jp/en/CRtool.php
http://sim.okawa-denshi.jp/en/PWMtool.php

and determined that in the 9V (12V actual) line a 330ohm (actual 325ohm) and 22uF capacitor,
the output should fluctuate between ~4,5-7V.

I assumed this should keep the led on constantly, but still the relay is opened and closed @ 143Hz.
I tried 1kohm and 2.2kohm but the relay does not open at all.

Any advice is welcome
In the mean time, I'll try to set up my raspberry pi to get a 143Hz source..