At £59 you will be amazed at what you get. DrDAQ plugs into the parallel port of any PC. I have used it on a 386, 486 and a Pentium, with Windows 3.1, 95 and 98 operating systems running the PicoScope and PicoLog software supplied with it. Updates of the software are provided free on the Pico Technology website. As supplied it comes with built-in sensors both to measure sound level and to display sound waveforms, ambient light level, temperature in the range 0 to 70°C, resistance from 0 to 1 M Ohms, and voltage from 0 to +5 V. Overload protection is provided up to ± 30 V. Resistance and voltage is measured via screw terminals. Additionally there are two FCC68 sockets for external sensors and a BNC socket for a pH probe. It would not be difficult to design other probes to fit the FCC68 sockets or screw terminals and I hope to supply details of some in future issues. There is also a digital output at TTL levels. Pre-calibrated temperature sensors to connect to these external sockets are available at £15 and have a range –10 to 105°C, and a pH probe at £35 having a range 0 to 14. Bought at the same time as DrDAQ these probes are considerably cheaper: DrDAQ, two temperature probes and a pH probe all for £99. (Prices as of October 2000.) The PicoScope software makes the computer into a storage oscilloscope with (i) a timebase range from 1 ms/div to 50 s/div, (ii) the capacity to display four different channels of data at the same time, (iii) triggering facilities, (iv) X and Y gain controls and (v) useful rulers to measure amplitude and time. The upper figure shows a screen display from an experiment to measure how the force (voltage) of impact with time changes as a model railway truck hits a foam buffer. Measurement of the contact time (time voltage is above 0 V) between a steel bar and a hammer hitting it can provide a means of measuring the speed of sound in the bar. Its Spectrum Analysis function shows the amplitudes and range of frequencies in a sound as in the lower figure. Its digital display facility will show in big numbers on the screen the value of frequency, voltage, temperature, pH, light level, sound level etc, depending on which sensors are connected. It makes a superb demonstration meter. The PicoLog software makes the computer into a chart recorder capable of collecting up to a million samples of data from the channels selected and displaying data and graphs in real time or afterwards. It can be used to show, for example, the cooling of hot water in comparison with the ambient temperature. A built-in spreadsheet is available to display the data or this can be exported to more sophisticated spreadsheets such as Microsoft Excel or Lotus 1-2-3. There are a host of other facilities available, usually only found on expensive data loggers, including alarms, recording after a set time, remote data collection, converting raw data into standard units for display, autosaving of data files on collection and statistical indications. If it has any fault it is not having a bi-polar voltage input to deal with work on electromagnetic induction, but that is a minor usage. For that I would look at one of Pico Technology’s other interfaces such as the ADC40/42 or, if you are after high speed data collection, the ADC200. However, for the vast majority of things done in school and college laboratories I am sure that DrDAQ will do nicely. The Web site below has a demonstration version of this software. Chris Butlin |
 Spectrum Analysis of a note played on a recorder |
 Force of impact as a model truck hits a foam buffer |
