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Of projects and SSRs - Page 2 — Parallax Forums

Of projects and SSRs

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  • phatallicaphatallica Posts: 64
    edited 2013-08-30 17:38
    For what you are looking to do - general purpose relay for various load types - it is tough to beat solutions like this relay from Parallax.

    Looking at the data that I linked in post #20, the Fotek part indicates leakage of up to 3mA. So, basically, it trickle charges the input capacitors in the CFL ballast circuit or LED driver circuit. Depending on the actual driver or ballast circuit, the behavior will differ. Some will flicker a few times when turning off. Some will flash every few seconds or minutes.

    If you can live with the flickers, then no big deal. If not, then disconnecting with an electromechanical relay may be necessary. There are some other tricks that theoretically would work, like connecting another load in parallel to bleed-off the leakage current. Since I have not used those myself, I would be guessing to some degree regarding good practices.
  • henrytjhenrytj Posts: 90
    edited 2013-08-30 19:04
    phatallica wrote: »
    For what you are looking to do - general purpose relay for various load types - it is tough to beat solutions like this relay from Parallax.

    Looking at the data that I linked in post #20, the Fotek part indicates leakage of up to 3mA. So, basically, it trickle charges the input capacitors in the CFL ballast circuit or LED driver circuit. Depending on the actual driver or ballast circuit, the behavior will differ. Some will flicker a few times when turning off. Some will flash every few seconds or minutes.

    If you can live with the flickers, then no big deal. If not, then disconnecting with an electromechanical relay may be necessary. There are some other tricks that theoretically would work, like connecting another load in parallel to bleed-off the leakage current. Since I have not used those myself, I would be guessing to some degree regarding good practices.

    Since the datasheet from that post didn't have a company name, It wasn't clear if it was Fotek, or just something similar. I just now noticed that the URL is to the manufacture site, which I failed to find when I searched for it. I simply saved the data sheet to my HD and looked at it later. So, now I know it is for that exact SSR.

    About the relay. Youtube videos that I saw that demonstrated microcontrollers and relays it was apparent that the relays make a rather loud clicking sound. This is part of the same reason that on the one movie the lighting person clicking the on/off switch real fast to simulate lightning didn't work out because the switch clicking was picked up on mic. The lighting guy was outside, and we could still pick his switch clicking on the mic inside the house. Many times shots were ruined because of some motorcycle 2 blocks away, etc. So, unless they make a virtually silent electro-mechanical relay, then I'm back to the SSR, which is what I'm rather heavily invested in now, anyway. When I had posted my first questions about this earlier this year, several people said "what you want is an SSR." So that's what I did.

    The Fotek ones don't seem to flash at all. It seems only these (older, I'm guessing by the looks of them) Crydom ones are doing that. Someone sent me (4) of these to try out. So I'd thought I'd put them to use in addition to the Fotek ones (of which I bought 4). I had thought of building 4 from the Crydom ones, and 4 from the Fotek ones. My microcontroller is currently wired for (7) outputs. I can add (5) more outputs before I max it out. (4 of the 16 are reserved for inputs. But I figure that 7 is sufficient for most of the lighting effects I plan to try.)

    I can live with the flickers as as they are really dim and only visible if you are looking right at the bulb. I just wanted to make sure that it wasn't a sign that the SSRs were faulty, or some other risk.

    Anyway, thanks for all the great help. Now to find someone with a good camera, and make some demo reel footage. I'll post a link somewhere here if the setup works out.

    H.
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