SSR and Arduino

Hello everyone!

I have been playing with an Arduino Uno r3 for about a week now (thus newbie).

I would like to connect a SSR in order to switch 7 pool lights on and off. The existing analogue timer switch (Theben SYN168A, specs nowhere to be found) for the lights can switch up to 16A (according to the writings on it) and it draws power from a 25A breaker. It switches power to 4 transformers which supply power to the lights (12V, 300W each lamp).

I would like to introduce an SSR (namely the 25A from them http://www.redlion.net/Products/Groups/DIN-RailRelays/RLY6/RLY6A/Docs/12021.pdf) before the timer. I understand that I should use a fuse in order to protect the SSR but I would like to ask if I should do anything about the arduino connection.

The SSR specs for control:

INPUT SPECIFICATIONS 1. CONTROL VOLTAGE RANGE: 4 to 32 VDC 2. TURN-ON VOLTAGE (MIN.): 4 VDC 3. TURN-OFF VOLTAGE (MAX.): 1 VDC 4. REVERSE VOLTAGE PROTECTION: -75 VDC 5. INPUT CURRENT (MAX.): 8 mA

which seem to within the arduino grasp.

Any thoughts would be appreciated!

At a minimum input spec of 4 volts you are already near the arduino maximum output of 5 volts. Without an "amplifier" transistor and a separate power supply (12 volts or so) you are chancing your luck. Only my opinion.

There are plenty of logic level SSRs available on fleabay at amazingly low prices that will satisfy your need and requiring no external components.

Many SSRs spec 3-30V. I have some 20A 240V SSRs that spec 3-30V input. I would look for a more-compatible SSR.

Thank you both for your input.

I'll try to find one with lower input control voltage or better yet use an external supply. The SSRs I am seeing on ebay are much cheaper but seem to be random switching SSRs or have very little info on their specs.

seems that I was wrong about zero crossing according to http://www.celduc-relais.com/all/pdfcelduc/PrincipeUK.pdf

I found a 40A SSR on Amazon for $11.50 and the matching heat sink for $7.59. Under $20 for both. http://www.amazon.com/dp/B005KPIX9A/ref=pe_175190_21431760_C1_cs_sce_dp_1 http://www.amazon.com/dp/B005D6145G/ref=pe_175190_21431760_C1_cs_sce_dp_2

I hope you are planning on using a heatsink.

I got the SSR to use for developing a controller for my hot tub, but I will be upgrading to a Crydom DW2450-10 (50A random) and a much larger heat sink.