working with USB relay controller board issue

[den372]

Hi, I am trying to use a USB relay controller to control devices in my house. I want to be able to additionally turn them on/off with a momentary switch. So If turn off a device thru software I can toggle its state with the manual switch and vice versa. Has anyone come across a relay controller board either USB, RS232, ethernet that includes the capability to integrate manual switches? Any help is appreciated

 

[ke5frf]

I have not seen the schematic for your relay board, but this would be a simple matter of connecting a manual switch in parallel to the relay contacts.

When the relay if off, you will be able to turn the device off/on with the manual switch. When the relay is on, it will override the manual switch (i.e. you won't be able to turn the device off with the manual switch until the relay is turned off). In other words, one has to be off to toggle the other one.

To correct a wording you used, you wouldn't want a "momentary switch". A momentary switch will revert to the normal state when you physically quit pushing it. You want a toggle switch, one that remains in the last state it was put in.

Do your relay outputs have NO and NC connectors to give you the option of switching from either state? If your relays have both NO and NC contacts, and if your load device (the circuit being switched), is non-polarized DC or AC, then you could wire the relay and a manual switch the same way a 3-way home light switch is wired (Like hallway lights where a switch at either end of the hall controls the same lamp)

Click on this image URL to get a schematic illustration of how a 3-conductor wire (red/black/white) is used to create a three-way switch circuit for the lamp.
**broken link removed**

 

[den372]

Thanks for the reply, I appreciate it. One of the problems I have is that if one is to manually press the switch to say set relay state to "off", then with software (a ir remote control thru a pc) I would like to be able to say set the state to "on" and then say "off" again with out manual intervention. I thought that a momentary switch would feed a flip flop or such that is handled at a logical ttl level. I thought with a regular switch if I manually turn it off, this would in effect disable the software circuit from action. Does that sound right to you? I like your idea of a 3-way switch, is this just like the way it is wired in the home for 3-way lighting?

 

[ke5frf]

Thanks for the reply, I appreciate it. One of the problems I have is that if one is to manually press the switch to say set relay state to "off", then with software (a ir remote control thru a pc) I would like to be able to say set the state to "on" and then say "off" again with out manual intervention. I thought that a momentary switch would feed a flip flop or such that is handled at a logical ttl level. I thought with a regular switch if I manually turn it off, this would in effect disable the software circuit from action. Does that sound right to you? I like your idea of a 3-way switch, is this just like the way it is wired in the home for 3-way lighting?

Yes, that is how 3-way switches are wired just like in a hallway or a room with two doors. All you need is for your relay outputs to have both a NC and NO contact...and of course the requisite that your load devices be non-polarized.

 

[3v0]

Start with uC (PIC) controlled relay board. This is easily done with a $30 UBW and a relay board which you can build or buy from several vendors

Connect the switches to several uC inputs. I suggest momentary tactile switches and an associated LED driven by the uC to indicate if it is on or off.

With proper programming you can manage the relays via the USB interface or the switches.

.

                        SWITCHES & INDICATORS
                         /\
                         |
                         \/
       PC<------USB---->UBW
                         |
                         \/
                       Relays

I can provide more details if you like. The UBW info is in my sig.

 

[leimech]

Operating house lights both by computer and manually

Original request:
Hi, I am trying to use a USB relay controller to control devices in my house. I want to be able to additionally turn them on/off with a momentary switch. So If turn off a device thru software I can toggle its state with the manual switch and vice versa. Has anyone come across a relay controller board either USB, RS232, ethernet that includes the capability to integrate manual switches? Any help is appreciated

...a little bit too late but really a 100% solution: IA-3088

This old but still available item is capable of operating lights both manually from multi location and multi switches around the house, as well as by a computer with no overriding effects. Manual switches wiring is simple. Two wires are connected in parallel to all the manual switches. The switches are simple momentary ones.

Moreover, this is a multi-drop creature. You can operate several units by a single RS-232 Port.

The unit is a little costy, as it includes a local operation/monitor panel to fit a main
central system, but you may choose a less costy version, IA-3088L, without the panel.