USB Line Switch

Turn on and off your personal computer peripherals, save power and money. Now suitable for Windows 7 without restrictions!



An older version of this product were published in the special issue "Mikrocontroller-Special 4" (ON/OFF USB-Lineswitch, page 48) of Elektor. Please note, that the descriptions and downloads, offered in this page, or not suitable for the circuit, described in the special issue.

With the "USB Line Switch" electrical consumers (e.g. printer, scanner, modem etc.) can be turned on and off by the personal computer (or with the push button in the device). The switch, used in the device, is working solid-state (triac), that means free of electrical noise and wearout. A light emitting diode shows the switch state. The device is designed as adapter plug. For the connection with the personal computer, an ordinary USB cable is used. More than one device can be controlled with a comfortable software for Microsoft Windows ®. An additional command line tool is available. Each device can store a short designation (e.g. the connected consumer), which will be shown in the applications.

The line part is optical isolated from the USB control electronic. The control electronic is supplied by the USB interface. If the personal computer is powered down, the connected consumer also is turned off (the LED is off). With this restriction, the USB Line Switch is especially suitable for computer peripherals. The advantages of the USB Line Switch:

Please note (for prospective buyers outside Germany): The device is equipped with three-pin plugs, especially used in Germany and some other european countries.

The differences to the "Elektor Edition" (Rev. 1.0):

Technical Data

Line circuit    
Supply voltage 90 ... 240V~, 45 ... 65Hz  
Load current max. 6.0A Fuse: 6.3AT
Turn on current max. 50A 50µs
Maximum restistive load 1400W  
Maximum inductive load 800W  
Own current consumption 0.0A (not measureable)
Number of switch counts (unlimited) electronic switch, free of wearout
Disconnection from line single phase  
Supply 5.0V DC (4.75 ... 5.25V), 40mA by USB at turned on PC
USB transmission 1.5MBit/s („low speed“) compatible to USB 2.0
Operation temperature range 5 ... 40°C  
Rel. air huminity max. 80% non condensing


The required software for this device is available as free download. The software package contains 32 Bit applications, which can be also executed under 64 Bit operating systems. They are suitable for

New: Now suitable for Windows 7 without restrictions!

The installation program is actualized. A new version of the LibUSB-Win32 driver set is used. This causes, that the applications of the package are suitable for Windows 7 (32 and 64 bit) now, without any restrictions!

Products and Prices

The USB Line Switch is either available as assembled and approved device or as construction kit. The gadget uses only conventional (wired) parts. The assembling of the kit may be no difficulty for experienced hobbyists.


This device is used at the high voltage line! You risk your life or the damage of other connected devices, if the gadget is not assembled properly. It is only allowed, to connect the circuit to the high voltage line, if it is housed in the destined casing. Less experienced hobbyists and electronic novices should not order the kit. For them, the assembled device is recommended.

PCB & Controller

the basic material

Construction Kit

for self made mens (and women)

Assembled Device

the connect and forget solution

This set contains:
  • printed circuit board (current revision)
  • programmed microcontroller (current firmware version)
This set contains:
  • casing
  • printed circuit board
  • all parts for the PCB, with programmed microcontroller
  • USB cable 1.8m
This set contains:
  • assembled and approved device
  • USB cable 1.8m
Price: Euro 15.00 Price: Euro 35.00 Price: Euro 49.00
Shipping cost category: A Shipping cost category: C Shipping cost category: C
Order number: ULS01 Order number: ULS02 Order number: ULS03

All prices inclusive german VAT, without shipping.

Shipping costs are calculated as real costs.

How to order and pay

You can order via E-Mail or FAX. Please give Your invoice and delivery address.

Order by E-Mail:
Order by FAX: +49-7541-81483

Delivery is only possible by prepayment! You will get a preliminary invoice as PDF file via E-Mail, which contains bank transfer information. After payment the goods will be delivered.

We apologize, that we can't offer you a more comfortable way for order and payment in the moment.

More informationen about order and payment...


The following free downloads are available:

Drivers and Software for Microsoft Windows 2000 up to "7" (english/german) Release ULS_Setup.exe 920kB
User Manual (german) Rev. 14 ULS_Manual_de.pdf 773kB
Construction Kit Manual (german) Rev. 15 ULS_Kit_de.pdf 775kB

Hint: The software package should be installed before connecting a gadget!


You will find information and downloads for software modules and drivers with the following links.

V-USB, Virtual USB Port for AVR microcontroller 
WinAVR, GCC development environment
LibUSB-Win32, USB drivers for Microsoft Windows ®