Control 24vac hvac dampers with this?

[cfrudolphy]

Beginning Arduino - Sprinkler Control Project

Randy, I have been reading this post with great interest. Thank you for sharing your expertise! This post is great!

I have gotten interested in creating my own Arduino project and I want to start with a sprinkler control system. Like your system and the other mentioned the sprinkler solenoid valves operate on 24VAC. I have created a simple diagram of what I need and very simple interconnects between the components. I would appreciate your comments regarding what I put on the diagram. If I have it about right and it is doable then I would start to purchase components, plug-in, etc.

Chuck

[sparkman]

Randy, I have been reading this post with great interest. Thank you for sharing your expertise! This post is great!

I have gotten interested in creating my own Arduino project and I want to start with a sprinkler control system. Like your system and the other mentioned the sprinkler solenoid valves operate on 24VAC. I have created a simple diagram of what I need and very simple interconnects between the components. I would appreciate your comments regarding what I put on the diagram. If I have it about right and it is doable then I would start to purchase components, plug-in, etc.

Chuck

Hi Chuck, one comment, you show a 5v power supply and a 12v relay module. You would need those voltages to match, so either change the power supply or the relay module (http://www.lightinthebox.com/8-chann...o_p411845.html).

Cheers
Al

PS I have an Arduino based sprinkler controller as well: https://forum.mysensors.org/topic/16...ler-controller, although I've changed it a bit since I posted it there.

[cfrudolphy]

Al thanks for the reply. The reason I show the 5VDC power supply for the relay board is based on this from one of Randy's earlier posts.

"Relay boards are available with inputs that are "active high" or "active low". The Arduino default for I/O pins is "active high". If your relay functions are backward to the device manager settings I.E. if the relays are On when the device manager is Off then your board is the wrong type, but there is a workaround. Post if you have that problem. Yours appear to be transistor driven rather than opto-coupled, so it is likely you are OK.

One caution: While we can us it temporarily for this test, in practice the 5VDC regulator on the Arduino really isn't designed to power 8 relay coils so it would be recommended that you provide a separate 5V supply for the relay board. When you do that it is important that the grounds between the relay board and the Arduino are "common", so the "GND" pins on the arduino need to still be connected to the "GND" pins on the relay board. You would connect he "-" or "GND" of the relay 5V supply to those same pins. Do NOT tie the "5V" pins of the Arduino to the "VCC" pins on the relay board. "

I know in that post that they were looking at a different relay board. The one they chose I could only find on Amazon and it was not available. So I searched for another. Maybe I misunderstand what is necessary.

Chuck

[sparkman]

Hi Chuck, the Arduino can use a large range of voltages as its onboard regulator will provide it with the 5 VDC it needs. This onboard regulator cannot provide the current relays typically need (although some Arduino clones have beefier regulators), so yes an external power supply is needed. You could use a 5 VDC power supply for this and also power the Arduino from it by using a different pin on the Arduino that bypasses its built-in regulator. You could use a 12 VDC supply instead and power the Arduino with it using the pin that feeds its voltage regulator. Both are acceptable options, but the relays need to match the voltage of the power supply. So if you use a 5V supply, use a 5V relay board, and if you use a 12V supply, use a 12V relay board.

Cheers
Al

[randy]

Randy, I have been reading this post with great interest. Thank you for sharing your expertise! This post is great!

I have gotten interested in creating my own Arduino project and I want to start with a sprinkler control system. Like your system and the other mentioned the sprinkler solenoid valves operate on 24VAC. I have created a simple diagram of what I need and very simple interconnects between the components. I would appreciate your comments regarding what I put on the diagram. If I have it about right and it is doable then I would start to purchase components, plug-in, etc.

Chuck

It all looks fine. Like Al said,you should either find 5V relays or add a second power supply for the relay board. I use POE Ethernet shields, so I only use a single power supply for the relay boards. If you are going to power the boards and relays from the same power supply, I would look for 5V relay boards.

That said, it will work fine fora sprinkler system.

[cfrudolphy]

Randy thanks for the feedback. Looks like I have a new project to work on. Will try to send updates on my progress.

Chuck

[cfrudolphy]

My First Arduino Setup

First, I want to thank all who contributed to this thread. It was invaluable help to me.

While mine is not for A/C dampers, mine is for an sprinkler system, instead of servo motors it is solenoid valves.

I currently have it hooked up with USB but want to add an Ethernet shield. Had some problems with the Ethernet shield and will start a separate thread for that.

I use a 9V wall wart to power the board, a 5V wall wart to power the relays, and a 24VAC wall wart to power the solenoids. Bought one new valve to test and it works! I have 5 valves in the yard to hook up to it and my wife wants me to add the 6th we bought. That will be next weekend to run the cable from the valves to the board. See the attached pic.

After I get it completely wired in I will start writing events to control it with more than just the on/off from the device page.

Again thanks all for your help!

Chuck