I am using two types of interfaces, Velleman K8055's & Mirrorbow's.
Both types of interfaces are USB controlled. Here are the details:-

Velleman K8055 Interfaces


  • 5 digital inputs (0= ground, 1= open) (on board test buttons provided)
  • 2 analogue inputs with attenuation and amplification option (internal test +5V provided)
  • 8 digital open collector output switches (max. 50V/100mA) (on board LED indication)
  • 2 analogue outputs:-
    • 0 to 5V, output resistance 1K5
    • PWM 0 to 100% open collector outputs max 100mA / 40V (on board LED indication)
  • general conversion time: 20ms per command
  • power supply through USB: approx. 70mA
  • dimensions: 145 x 88 x 20mm / 5.7 x 3 x 0.8"
  • Download Illustrated Assembly Guide
    Download Programming Userguide

    Mirrorbow Interfaces


  • 26 IOs – 24 general IOs + PWM output and Frequency measure input
  • Power – USB Powered
  • Maximum loading on any output 10mA subject to not exceeding 100mA total on all output pins
  • All IOs logic level except for inputs configured as Analogue to Digital which have a range of 0 to 5V
  • Maximum read speed (from host PC) approx 1mS (Windows on the host usually defaults to 500uS for a command write and 500uS for a response, thus a tight software loop on the host can switch the state of a port every 1mS)
  • PWM
  • Output frequency range from 2.9KHz to 1MHz with programmable mark/space
  • Frequency Counter
  • Input frequency range 0.2Hz to 5.25MHz logic level
  • Port1 change poll mode
  • Any change returns a message (including changes to output state on the port)
  • Polled every 25mS
  • Port2 change interrupt mode
  • Any change on lower 4 bits of port2, restricted to changes on pins defined as inputs
  • Will catch fast changes, however each change interrupts the processor on the USB 25IO so subjecting this input to continued rapid changes can result in loss of communication with the must be taken with this mode
  • Recommended max change rate – 40 times/sec
  • Use this mode if you have short duration pulses which could be missed in poll mode above
  • Analogue to Digital Converter mode
  • Selectable as :-
    • No ADC inputs (all logic IOs) o 2 ADC inputs
    • 12 ADC inputs
  • Measurement in the range of 0V to 5V
  • Resolution 10 bit , returning in hex 0000 to 03FF
  • Servo Mode
  • Port2 can be configured as up to 8 servo outputs
  • Designed to drive the signal line of standard servos
  • Each output can be either off or programmed to output a pulse of width between less than 1mS to greater than 2mS. Each servo output will continue to transmit the programmed pulse chain continually.
  • Data Acquisition
  • Master sample frequencies of 16kHz, 8kHz, 4kHz, 2kHz, 1kHz and 500Hz
  • Port1 and Port2 digital acquisition up to 16Khz
  • Analogue to Digital acquisition up to 16Khz
  • Analogue to digital data channel modes of 1 channel, 2 channels, 12 channels with Port1 and Port2 state
  • Download PDF Userguide

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    Dave Ault

       Midlands, England.

       HNC in Microelectronics.


       Programming, Electronics,    Flight Simulation, Guitar,    Banjo, Mandolin.

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