Using USB to control external device

[dvortex]

Hello,
This is my first post.

I have been at ABB working with power transformers for the past 7 years, and before that I was in university studying operations management and working... Last time I was involved with "low level" electronics was like 15 years ago...USB wasn't as commonplace then. But I changed jobs about a year ago. I have been tasked with evaluating the feasibility of a new potential product. I need to make a "proof of concept" prototype. Here is my issue:

I need to control 3 channels, perhaps add a few spare ones for future needs, but we are talking of no more than 8. I want to control them with a computer trough the USB, using a simple program where you can simply switch any contact on or off. I would imagine that there are a lot of people using USB to control all kinds of devices, I am sure that they exist. But I don't know the correct terminology. Where can I find this and what is it called?

Since this is a prototype, I don't mind buying some form of development kit. Ideally a small simple card with insulated contacts that can switch 24 V and is powered itself from the USB.

 

[Nigel Goodwin]

USB itself is quite complicated, by FAR the easiest option is to use a USB to Serial converter, then use a PIC (or other micro-controller) to respond to the serial commands from the computer - the computer just needs to be running a standard serial comms program, or you can write your own specific program on the computer.

Probably the easiest, and cheapest, way is to evaluate it with an Arduino Uno - it's a development board for an AVR processor, and already includes the USB/Serial converter, and the Arduino IDE even includes a serial comms program so you can send commands to the Arduino, and receive responses back.

You can also buy 'shields' which plug directly in the top of the Uno, which are freely and cheaply available - including ones with multiple relays, which sounds perfect for what you want.

http://store.arduino.cc/arduino-4-relays-shield

Basic Arduino relay shield example

The Relay Shield features four high quality relays and provides NO/NC interfaces, four dynamic LED indicators to show the on/off state of each relay, and the standardized shield form factor to provide a smooth connection to Arduino compatible boards. Product…

arduinolearning.com

 

[rjenkinsgb]

You can get ready-made USB relay / USB input-output units quite cheaply.

Just search "USB relay i/o" on ebay for a range.

These seem quite common:

Ontrak ADU208 USB Relay I/O Interface | eBay

Find many great new & used options and get the best deals for Ontrak ADU208 USB Relay I/O Interface at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Or from many hobby / robotics / home automation suppliers, eg.

USB Relay Controller with 6-Channel I/O - DEV-09669 - SparkFun Electronics

This USB Relay Controller / Data Acquisition Module, from [Cana Kit](http://www.canakit.com/), allows computer controlled switching of external devices as

www.sparkfun.com

There are also many Ethernet-connected types, which can be more versatile than USB - eg.

ETH484 - 4 X 16a Ethernet Relay for sale online | eBay

Find many great new & used options and get the best deals for ETH484 - 4 X 16a Ethernet Relay at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Ethernet I/O - Ethernet Input output | SCAN UK

Welcome to our Ethernet I/O - Ethernet Input output page. Here you will find leading brands such as Brainboxes.

www.scan.co.uk

 

[dvortex]

I can stop playing that U2 song on repeat because now I have found what I was looking for. Thanks a lot guys!