RS232 Relay Switch

[Petrusvb]

Hi

I am new to electronic but are currently in a jam with one of my clients. They have an access gate at their gym for which i wrote the software application. The gate can be opened in two ways:

1. From a normal button switch in the gate
2. From my software via the serial port by supplying codes to a PC board that will decide on receipt of the code one of the following situations (open gate once and close, keep open or reset gate).

The person who did this board don't exist anymore. The pc control of the gate has gone faulty and I am unable to fix it as the problem seems to be on the PC board.

I am looking for a diagram that will allow me to switch a relay on and close a relay from the serial port.

If the other functions can be incorporated it will be great else I will do it via the software, but I think this will be quite advanced.

I have search the web, but don't find anything except complete kits and the shops I visited in South Africa said I must bring a circuit and they will supply the parts, no kits.

Also I need to know if I can run the switching form the serial port completely or must an additional power supply be added (the existing board has an additional power supply).

As serial ports is becoming a thing of the past can this be done via USB and if so how?




Help will be appreciated.

 

[Reloadron]

This pdf file although for a kit does include a schematic of the circuit. Overall it shows how relays can be activated from a serial port. It may be of some use to you.

Yes, you would need a separate power supply as there is no easy way to get power from a RS 232 serial port.

Can't help on the USB ways of doing it.

Ron

 

[BrownOut]

That's brilliant, except now you have to figure out the code. That shouldn't be too bad if you know how to program this controller. But it you don't, best to just buy the kit, which should give you access to the firmware. If you don't have a serial port, there are a myriad of USB to serial convertors that you can use in conjunction with terminal programs. Alternatively, you can use products like those from Wiznet to control your relays directly using USB. Your time is better spent learning to use these products rather than trying to come up with your own USB interfaces.

 

[Petrusvb]

Thank you

Thank you for your replies. As I know more about programming than electronics the complete assembled kit looks the best. I will contact them and see if they are willing to import to South Africa.