Reddit reviews SainSmart 8-Channel Relay Module

You won't be able to do it cheaply. Especially the monitoring part. Individual monitoring devices cost as much as individual switching devices, a baseline of about $5 each just for the components.

Basically whatever kind of smart outlets you can find will be what you'll have to use for all the outlets. You can find some switching devices in modular form like Lutron Powpak also to do switching in the backplane but those are at least as much money as the outlets.

Just to control them, however, you could use a relay block made for hobby usage. This would be fairly cheap on the order of $1.25 per switch from Amazon but you'd have to rewire the whole house, put these relays + an Arduino-ish controller in a separate box from the main breaker box. And you are basically putting together an unapproved line voltage device which is not insurable.

Amazon sells Arduino-ready relay modules like this one: http://www.amazon.com/dp/B0057OC5WK/

Maybe isn't perf cry for your application, but studying its design might be a good starting point.

This is a lot easier than I thought. The relays I'm controlling are GE RR-7 relays which maintain their state on or off. So all I have to do is send a quick 24vac pulse to the on/off side to set it. I think I'd tear apart the kitchen panel for light control... there I would have access to the bundle of 12 on/off pairs and 24vac common to put the relays. These Sainsmart relay modules look like they will work nicely.

You could try a "sprinkler controller" like Open Sprinkler or Open Sprinkler Pi ($75-$150 - available here ) which would give you a nice user interface, weather forecast integration, etc etc. Or you could put together your own Sonoff replacement with a Raspberry Pi-controlled relay like this - $10 for 8 channels - how-to video here.

You'd use a relay board like this hooked up to some electrical outlets. The relays themselves are activated by a 5v signal from the Arduino, those boards are set up to hook directly to the Arduino output pins with the isolation portion already set up. You run 110v in to those screw terminals and the outputs to however many outlets you need. Keep in mind each relay can only support 10 amps on the board I linked to, if your lights are drawing more current than that you'll need to use bigger relays.

Don't try to connect the Arduino directly to those VFD inputs. Instead, use a 5V logic level relay board and connect the contacts of the relay between the VFD's DC Common (DCM) port and the VFD input (DI1-6) port.

Of course, you could also use a mosfet or other transistor as a "solid state" switch, but with a relay you can be assured that the VFD will be isolated completely from the Arduino. Many industrial PLCs that would control a VFD such as this have "relay outputs" that do just this.

I'm not sure what your level of proficiency with electronics are, but almost everyone who's interested in this sorta of thing understands relays, and I'm sure you can figure out how to hook the relay board to the gpio + power.

SainSmart 8 Channel relay board

they also have 16 and 4 channel ones

I hooked the 8 channel one up to some hand rolled/crafted electromagnetic hammers and a wind chime as a demonstration for a friend.

> Edit: The microcontroller will not be controlling the afr and other engine systems. It will only be controlling whether the car is in eco mode or sport mode effectively.

Oh, well, that changes the whole thing!

In that case, yeah a simple tablet running a custom python program for the GUI will suffice, when paired with an arduino. Windows/Linux/Android all have the password login that you're looking for.

You'll still need an Arduino for the switching though, and some sort of either relay board or transistor array to actually flip switches. Arduino's are too low-power for that on their own. I'd be willing to bet that 8 channels is all you'd really need (for controlling the lights, and power to the ECU for the killswitch).

It'd depend on your current fueling setup if an arduino will push enough power to switch the ECU, but there's a pretty good chance that it will suffice on it's own without using a relay channel.

This is all similar to a project I've got right now. It's a Pi datalogger that uses an Arduino to read TPS values (along with a GPS chip for speed/position), and then a python program to display it live-time and do the actual save-to-file and display-output stuff.

Using this one: http://www.amazon.com/gp/aw/d/B0057OC5WK/ref=mp_s_a_1_2?qid=1405292686&sr=8-2&pi=SY200_QL40

Yeah. You can do it all analog if you can get it down to 26 outputs.

Then you just need transistors for the duplicates. Easy peasy.

Edit: You'll have your work cut out for you if you just set out to Google-learn about transistors and relays. This project would be quick with a bank of four of these, but it would also be unnecessarily bulky and expensive. You can do everything those do with just transistors since you're only powering LEDs.

Thank you for the response. Everything you've said makes sense and is quite helpful. What I'm still a bit fuzzy on is the way this acts as a NOT gate. It's clear that it has reversing logic, but based on the schematic, I'm confused where the output gets its power when the input is FALSE. am I correct in my understanding that the difference between TRUE and FALSE (at the output, with the opposite input) is that TRUE is grounded whereas FALSE is not. The Vcc in the case of FALSE is actually provided by the connected device (in my case, relay power)?

Ultimately, I'm looking at QTY48 relays controlled by QTY6 595 shift registers. The relays will switch LED light strands for christmas lights for my boss. (It's great! I get to tinker with the design and implementation, and he foots the bill). I'm going to use external power for both, these relays and the shift registers. At first I was thinking I'd buy a few of these, but after finding this darlington array, wiring in a few relays doesn't seem like that big of a task. Then again, I probably won't get 8 SSR relays for that price. I guess I just want to understand how to build it myself before I buy it off somebody else...

Thanks again for taking the time to help me out!

You will have a hard time finding a conventional remote monitored humidity system that remains accurate at the high humidity ranges which a fruiting chamber needs. Most of these systems you are probably seeing are meant for typical temp and humidity ranges for human comfort which is around 50% RH, not 95% RH and above.

I put together my own system using a PLC with proper humidity and temp sensors. It's not the convenient "touch and access" system you are probably looking for but was the only thing I could come up with that was suitable for high humidity environments. In the long run i'm happier using a PLC and accessing it the hard way because of how versatile it is. I can still see temps from my mobile using the built-in webpage on the PLC and I also get email alerts when temps or humidity ranges are out of spec so it does everything you are looking for but requires some technical suave to configure and use.

I also have humidifiers, ventilation and a small heater connected to my PLC which automatically regulates the environment for me and I can adjust it remotely as well. This requires a relay board to go with the PLC. It also requires learning PLC coding which isn't very difficult and is well documented.