USB module for monitoring multiple on/off switches

Why USB? It can be done almost directly with a serial or parallel port.. Try smarthome.com, jameco.com and jdr.com.

Directly, as in one port? I need to monitor multiple alarms and need multiple ports, as in 8 or more.

Best, Christopher

RS-485 is a two wire serial port that can support multi-drop peripherals. Translator adapters RS232/RS485 can be purchased for about $25.

Actually, I was talking about simply using a pin on the port. For a serial port, you got two pins, and for a parallel, you got 8-10, IIRC. Using direct IO. You read the port and see the logic state if the pins...

No buss involved..

Another option is a Dallas ds2490 (?) USB to one wire adapter buss (~$25). Then, with ds2401's or DS2405's (~$2 each) you can sense a bunch of spots, but the SW to do so is more complex. I've had my best luck with the Linux version of the Dallas SW than the windows version...

Makes sense and cheap but you did mention serial port.

WTF is a "buss"? (obviously you work in the electrical field)

Manufacturer of fuses, and probably a bunch of stuff I'm not aware of. Also (and I don't know if this comes from the manufacturer, or some alternate source), a "buss bar" is a power or ground bar in a circuit breaker panel.

The name has leaked over to become an occasional alternate spelling of "bus" -- it happens enough I'm not even sure I'd call it a mis-spelling.

Buss is an old word for kiss. A data bus (only one "S" here) is an interface between a computer and another computer or some other device to exchange data. It can also refer to a data connection between components within a computer.

How many feet can a USB cable be run before it ceases working even at the slowest USB speed? If I need to run the cable to the front door, back door, refrigerator, freezer, garage doors, every window, some motion sensors, a couple of smoke alarms, and a keypad, that's a lot of cable. On the other hand, polling each sensor 5 times a second is probably way overkill.

Four USB-to-parallel-port devices, with the parallel-port devices (with data and control lines, you may be able to sense 10 contact closures each) spread around the house, might be sufficient.

USBmicro U401 or U421 USB interface.

Thanks!!! Also found

Best, Christopher

Sorry, but you can't use those devices the way you mention. They only work with print drivers.

You may want to look at using rs232 boards like below and use it with a USB to serial adapter. Be aware that USB boards (like bottom activewire) that do not apper as a serial port but instead use dlls and such, can require significant programming experiance.

This appears to be an ideal solution (or at least close to it) for a project using a PC to monitor and control alarm sensors, sirens, etc. The gentleman will also need a power supply to operate motion, smoke or glass break detectors as well as for sirens or strobes.

I don't sell this device and I have not tested it so due diligence, please. I do sell power supplies, alarm detectors and such in case the OP needs a source for same.

Oops. I forgot to insert the link to the GV-IO device. Here it is:

Do you need/want to absolutely restrict access to a single computer? If not, my preference would be for TCP/IP-based ( not usb, not RS-xxx, not bus).

WebControl is a $35 TCP/IP-based (web) device that I use and can recommend that would give you 8 TTL in, 8 TTL out, 3 analog in, multiple 1-wire temperature input, HIH-xxx humidity sensor input, etc:

Input Digital Inputs 8 Analog Inputs 3 Maximum Digital Input Level TTL 5V Maximum Analog Input Level 3V Mnimum Input Level 0V Output Number of Output 8 Output Level TTL 5V Output Current MAX 30 mA Programmable Timer Number of programmable timer events 20 Sensors DS1822 Temperature Sensor 8 Honeywell Humidity Sensor 1 Power Consumtion Without Load 5MA With Full Load 240MA Power Supply DC (recommend) 6V to 7.5V AC (when DC not avaliable) 12V

$35.00 + shipping -- A steal IMO.

Interface is either with browser or command-line.

or you can write your own GUI

Available/find suppliers through Amazon.com

$35.00 + shipping -- A steal IMO.

I have two boards of an earlier version (hardware 2.02) than what is now shipping that was fussy about the exact 1-wire temperature sensor used. The contact tech team was very responsive and had the firmware re-written by the team in Britain.

HTH ... Marc Marc_F_Hult

My preference is also TCP/IP. I assumed that such a solution would be too expensive. Thanks!!!

Best, Christopher

It even supports email on digital I/O state change. Awesome! Thanks again Marc.

Best, Christopher

Yes. And one can create rules using Boolean AND/OR logic with the various inputs including TTL-level logic, 0-10vdc analog, temperature, Relative Humidity, and Date+Time and delay timers to control the TTL outputs. The Real Time clock (RTC) can be kept accurate by Network Time Protocol (NTP).

I'm considering these as an integral part of multi-unit, open-loop geothermal HVAC for our house. Hardware for RS-232 and RS-485 inputs are on the WebControl PCB but are still unsupported by the firmware. I had a useful conversation with the manufacturer about the potential to support BACnet. They are up against memory constraints in the microcontroller.

At $35 including a steel case, IMO it's quite a bargain compared to some other devices.

HTH ... Marc Marc_F_Hult