Resistive Or Inductive?

[Ratmandu]

Since I'm not going to be able to get a christmas display up this year, I thought I would put my time towards doing a home automation project. I'm planning on replacing all the light switches in the house with a homemade SSR and a Atmel ATTiny, where all of them are wired together either with i2c, or more likely, SPI (possibly even CAN) and with a pushbutton for manual switching.

What im wondering though, is if the coop SSR schematic is safe/usable for compact flourescent bulbs, which is what we have replaced every light in the house with over the past year and a half. (saved us a lot of money btw)

[DynamoBen]

What im wondering though, is if the coop SSR schematic is safe/usable for compact flourescent bulbs, which is what we have replaced every light in the house with over the past year and a half. (saved us a lot of money btw)

Yes if you don't dim them, just on/off. However there is a catch, the ballast on the compact fluorescent bulb might not sink enough current to keep the SCR in its current state (on/off). Most SCRs need a minimum current passing through them to remain in their state, which is something to consider as you are doing this.

An alternative that you might consider for on/off control is the Crydom D2W203F. They are replacements for electro-mechanical relays. They run at low voltage, with very low current; plus they don't make that horrible clicking noise.

[Ratmandu]

Ok, Thanks for the reply.

Also, I should mention that in one room, (my room, first to be done with this) I have 2 CFL bulbs in the same fixture, to the same switch, so the two together should sink enough current to keep it on, ill have to run some tests on the single bulbs though. As for the crydom parts, I'll keep those in mind, but i have enough parts to make single SSR boards for the whole house already.

I'll probably start a google code project for this once i start doing everything, with microcontroller code, and eagle files for all the hardware. And the specific part I will be using for this is an Atmel ATTINY 84, but will also be compatible with the 24 and 44. The reason for this chip, is the relatively small size, availability of SMD part as well as PDIP, inclusion of the universal serial interface, and best of all, a built in temperature sensor. Plus the fact that I can hook up a HD44780 based LCD to it and still have more pins left over for communication, light switching, and control.

EDIT: I went and set up a test with one of my SSR boards and a desk lamp with one of the bulbs in it. Bulb is marked .200 amps, 14W, and lit fine, and stayed lit for well over 5 minutes. It looks like im good to go. Thanks for the quick help.

[DynamoBen]

BTW if you run into the state issue a work around is tying a power resistor inline on the hot side prior to the lamp. CAUTION: the resistor will get hot so you will need to keep that in mind for placement.