Reddit reviews SunFounder 2 Channel DC 5V Relay Module with Optocoupler Low Level Trigger Expansion Board for Arduino R3 MEGA 2560 1280 DSP ARM PIC AVR STM32 Raspberry Pi

I would think it's best to power the motors with a separate power supply from the Arduino power since the motors will draw a lot of current. Instead of powering the motors from the onboard 5v supply, run a separate supply through either a relay module or a motor controller board. Like these: relay, motor driver.

Thank you :)

I used a simple 5v relay module, very similar to this one here: https://www.amazon.com/dp/B00E0NTPP4

The one I'm using is very old, bought it years ago and I don't remember w here, but the one in the amazon link above is very close. In my video, I show the module starting at around 6:58 - https://youtu.be/1mtX4kB1EEA?t=418

You can also use a transistor for this. Pretty much any logic-level transistor will do, or any transistor that can be turned on with 5v of power. I'm working on another project to control an RGBW LED strip, for that I'm using transistors and the models I'm using are IRL2203 and IRLU024 MOSFETs.

You can look in to these relay modules they are cheap and easy to use. As for your EM interference on you previous project. Did you switch the relay with an output of the Arduino ? Because relay's are using around 50mA when switched while an output can only provide 20mA. The Arduino resets as a result.

i would use a plain old relay.

something like this and then like you said, heat if too low, fan if too high. i prefer digital temp probes like the ds18b20. It comes in a nice water proof package so you can spill beer (or wine?) on it without worry.

I used a reed switch connected to a GPIO port to detect if the door is open. I used Twilio to send me an SMS. I used a relay board (like this one) in parallel with the manual pushbutton to toggle the door. And I used Python to serve the site. Let me know if you have specific questions.

Most simple relays I've used have 3 connections, allowing 2 choices - either NC or NO. Just wire it for what you need.
I can't help with ordering to CA - but this is one where you can see in the pic that you can wire it either way.
https://www.amazon.com/dp/B00E0NTPP4/ref=cm_sw_r_cp_apa_i_67eACbFK3XZPA

I am not sure if you are asking how to do this as well as if it's ok to do it but Check out this relay.
https://www.amazon.com/gp/product/B00E0NTPP4/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

I use it to trigger my Garage door from a Pi. It also works with an Arduino.

Thanks, you're right actually. Since my question is safety related, it's more than reasonable to be precise.

I meant this one

This should work for your relays: http://www.amazon.com/SunFounder-Channel-Shield-Arduino-Raspberry/dp/B00E0NTPP4/ref=sr_1_4?ie=UTF8&qid=1449242914&sr=8-4&keywords=arduino+relay+board

It's "meant" for an Arduino, but should work with the Pi with a bit of work. It triggers on a 5v input from the Arduino, so you'd need to get the 3.3v line from the Pi's GPIO up to 5v to make it work.

You'll want to figure out the pinout of that plug with a voltmeter. I'm guessing that one of those is common and the other two are for separate banks of LEDs. To control these, you'd run the common straight through and interrupt the two banks with the relays.

As far as Pi vs Arduino, you'll have to do some tinkering either way. Neither have a RTC (real time clock) built in, so you'll either need an RTC shield or connect the Pi to a network connection so it can get the time via NTP. The Pi's main disadvantage is the 3.3v GPIO, while the Arduino's output is natively 5v.

Personally I'd use the Arduino and a cheap RTC: http://www.amazon.com/Donop-DS3231-AT24C32-precision-Arduino/dp/B00HCB7VYS/ref=sr_1_2?ie=UTF8&qid=1449243489&sr=8-2&keywords=arduino+rtc

So, here it goes, feel free to PM if I leave anything unclear.

Sorry if I was unclear....you need to have the Pi first and then building an outlet or switch is pretty cheap. The Pi and other stuff (case, sd card, powersupply) will total out to about $50 but is completely worth it because of all the other stuff you can do with them (media server, web server, whole home ad blocking, game emulation, etc)

Ill start with how to get the pi to control things and then explain how to get the echo to control the pi...

If you only want to control led strip lighting IIRC a lot of them have IR remotes and the simplest solution is probably to build an IR blaster (you will need a couple basic electronic components but cost is less than $10 even if you buy from a radioshack), and then use LIRC (http://www.lirc.org/) to emulate the remote with the Pi. The added bonus is you can then control any other IR remote device (you tv, stereo etc).

If you don't go the IR route you will use a relay to act as a switch. I have used a number of these guys for various projects: relay The basics of a relay is a small voltage opens and closes a magnetic switch that is controlling a much larger voltage. So the 3.3 volts a "general purpose input/output" (GPIO) pin a raspberry pi generates can open or close the other side of the relay that can handle household voltage. I should add the caution..."don't mess with household voltage unless you really know what you are doing you can burn down your house and kill yourself". Anyway the idea is you build a box (think electrical gang box from a home improvement store) where the power comes into the relay and then leaves onto an outlet that you want to control. I have built a couple that are the relay and outlet all in one retrofit outlet box all mounted into the wall (the relay is hidden behind the outlet it is controlling. Then you run some small gague wire (telephone 4 conductor wire works well) from the relay to the pi. The end result is the pi sends voltage on one line to the relay, the relay closes connecting the household voltage to the outlet and whatever is connected to the relay turns on. I usually include a inline 10amp fuze as well because the relays are only rated to 10A and all my breakers are 15A.

Anyway, now you have a raspberry pi that can turn an outlet on and off to tie to the echo you use a piece of software called HA-Bridge . It allows you pi to emulate a smart home device Alexa will recognize. Alexa sends on/off command to the emulated device and the pi can trigger a script to carry out your desired intent.

Right now I can walk into my basement and say "Echo, turn on the basement" Where basement is a group (grouped int he Alexa app) of several devices all emulated by the pi and the pi turns on the Tv and receiver with ir commands from LIRC, the lamps controlled by a relay turning on and off the power to a couple outlets and the Christmas Tree that is plugged into a single relay controlled outlet.

Hope this helps, it sounds like a ton of stuff but is very doable.

Sample relay or mosfet

I really wouldn't worry about relays failing. You aren't talking about tons of cycles or fast cycles, high amperage, or whatever. Using a SSR would be fine for sure, I made a PID to control a freezer ~10-15A draw using a 40A SSR that has run day and night for years without failure.
Here's one from amazon that I have used.

https://www.amazon.com/SunFounder-Channel-Optocoupler-Expansion-Raspberry/dp/B00E0NTPP4/ref=sr_1_5?ie=UTF8&qid=1494422744&sr=8-5&keywords=arduino+relay

First this going to be removed as what to buy questions go in the meagthread sticked at the top of the feed. As for the fireplace, I don't recommend it when you're dealing with something that could set you house on fire. People do put switches on fire places here though. You can use any switch for the fan as all HomeKit switches support timers. Make a scene that turns the fan on. Set an automation for when the fan turns on turn on the scene. Make sure that the timer setting at the bottom is set to how long you want it on.

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Edit: Found this on a forum.

>I was able to get this to work, though with a much different setup than I was initially envisioning.

>
>The fireplace I was working used a low-voltage switch on the wall with a 2-wire cable between that and the fireplace guts (below the firebox). It also has 2 outlets in that same area: one labeled REMOTE and one labeled FAN. As far as I know, both outlets are always on and the labels are just for fun.

>
>Here is what I did:
- Caseta plug-in lamp dimmer plugged into one of the outlets
- Set this dimmer to switch mode (no dimming) - see Caseta Advanced Installation Guide for details
- Plugged a 5V DC power adapter I had laying around into the dimmer
- Connected the output of the DC adapter to the input of a relay. I used the Sunfounder 2-channel 5V relay module
- Cut the cable that went to the wall switch and connected it to the output of the relay instead of the switch

>
>This solution does completely disable the wall switch but - in my case - it was in a crappy location anyway.

>
>Some other notes on this:

>
>- I got a 2-channel relay module since it was cheap and readily available but only one channel was needed
- I was a bit worried about the heat in the area with the electronics but I measured the temperature of the dimmer with one of those point-and-read thermometers after the fireplace was on for a while and it came up at 105. The specs for the Caseta say the operating temp tops at 104 but it's been running for over a month now and - so far so good.

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Maybe I'm not quite following, but wouldn't you use something like this bulb:
https://www.amazon.com/BYB-Ceramic-Infrared-Emitter-Brooder/dp/B00HFNZ59Q

plugged into this to secure it:
https://www.amazon.com/Simple-Deluxe-Listed-Aluminum-Reflector/dp/B01E9IY6US

with one of the wires cut and running through this to switch it on and off:
https://www.amazon.com/gp/product/B00E0NTPP4

there are easier solutions but since this is DIY I recently put together a circuit using one of these
https://www.amazon.com/HiLetgo-Version-NodeMCU-Internet-Development/dp/B010O1G1ES/ref=sr_1_1?ie=UTF8&qid=1466965785&sr=8-1&keywords=nodemcu+v3

It's programmed via the arduino IDE and is simple enough with a bit of googling for any programmer to get working. I have it connected to one of these
https://www.amazon.com/SunFounder-Shield-Module-Arduino-Channel/dp/B00E0NTPP4/ref=sr_1_4?ie=UTF8&qid=1466965844&sr=8-4&keywords=arduino+relay

3 wires from the nodemcu to the relay. VCC, ground and one of the datapins. Just make sure you use the 5V pin for VCC as the 3.3V ones didn't work.

Then apply power to the relay and he nodemcu. I used an old 5V cellphone charger that I cut the plug off of and direct wired it to the boards. After that I made a short 6" extension cord and split one of the wires. It goes into the relay. After that it just works.

You will need a way to solder the wires and a breadboard lets you test before doing the final wiring.

I tinkered with two different methods, both of them use Gordon's WiringPi library to manipulate the GPIO. One of the setups uses a PowerSwitch Tail II to power off the entire machine and the other method used a simple relay to toggle the reset button. My preferred method was the firs method because it FORCED power off no matter how frozen the mobo was.

By the way - the close observer will notice that the PowerSwitch Tail is really just a relay enclosed in a box. I prefer to use it when handling 120V AC so I don't make shiny sparks.