DrDAQ Data Logger

 

Built in sensors for light, sound and temperature

Measures pH - just plug in any standard electrode

Complete and ready to use at a fraction of the cost of other data loggers

Output for control experiments

PicoLog (data logging) and PicoScope (oscilloscope and spectrum analyzer) software

 

 

DrDAQ : Internal Light Sensor

 

Light Sensor

The internal light sensor can measure a wide range of light levels, from weak moonlight through to strong sunlight. Unlike most light sensors, it has a fast response so can measure quickly changing signals such as the flickering of tube lights. The waveform below was captured by holding DrDAQ up to a computer display. It clearly shows the monitor has a refresh rate of 72Hz.

 

Sample Waveform

 

DrDAQ : Sound Sensor (Microphone)

Sound Sensor

DrDAQs internal microphone can be used in two ways, firstly to display and record sound level (sound level meter) and secondly to display the actual sound waveform.

The sound level channel works over the 55dB to 100dB range (approximately from quiet conversation to a loud motorcycle). The human ear does not respond equally to all frequencies (it peaks at about 3kHz which corresponds to a baby crying). To allow for this non linearity, sound level has been 'A-Law' weighted to approximately match the response of the human ear. Typical uses for this channel include:

monitoring ambient noise levels in the class room (do they increase when the teacher is absent?)

monitoring traffic noise

showing how sound level decays with distance

recording the 'dawn chorus'

Unlike many data loggers, DrDAQ can take readings very quickly (up to 15,000 per second). This means that it is capable of displaying sound waveforms both in the time domain (oscilloscope view) and in the frequency domain (audio spectrum analyzer view). The waveform below shows the response to someone whistling at 1kHz.

Sample Waveform

 

 

DrDAQ : Internal Temperature Sensor

Temperature Sensor

The internal temperature sensor consists of a precision thermistor housed in a robust case. It measures over the range 0 to 70°C. Resolution is better than 0.1°C and accuracy better than 2°C (at 25°C). Temperature readings can be displayed in Centigrade, Fahrenheit or Kelvin. If you need to measure over a wider range, or remotely from the DrDAQ consider using a waterproof / weatherproof external temperature sensor.

The waveform below shows variation of ambient temperature over a 24 hour period.

 

Sample Waveform

 

 

DrDAQ data logger : Voltage Input

Voltage input

Voltage in the range 0 to 5V can be measured using the screw terminals on DrDAQ. Resolution is 5mV and accuracy is 3%.

Unlike many data loggers, DrDAQ take readings very quickly (up to 15,000 per second). This means that the DrDAQ data logger is equally suitable for measuring events of a short duration (such as the 'bounce' of a mechanical switch) or for long term data logging (the discharge of a battery over several days).

The waveform below shows the voltage in a simple RC charge/discharge circuit.

 

Sample Waveform

 

 

DrDAQ : Resistance input

Resistance Input

The screw terminal inputs on DrDAQ can be used to measure resistance over the range 0 to 1M Ohm. Resolution and accuracy are better than 2% (at 100K). By connecting a potentiometer to this input, position can also be monitored. The waveform below shows the swing of a pendulum recorded using a potentiometer.

 

Sample Waveform

 

 

DrDAQ : pH Input

pH input

Most data loggers can not measure pH directly and require an (expensive) external amplifier. With DrDAQ the pH amplifier is built in. DrDAQ can be used with any standard pH electrode, details of a suitable (optional) electrode are shown below.

For basic measurements, DrDAQ is ready calibrated to give the correct pH readings. For accurate measurements, a facility is included to calibrate the electrode. As pH is proportional to absolute temperature, there is an option to compensate for temperature changes (using either the internal or an external temperature probe). Despite DrDAQs low cost, these two forms of calibration make for extremely accurate pH measurement.

The waveform at the bottom of this page shows the pH of a beaker of milk as it turns sour.

A complete kit which comprises of all the items you need to measure pH is available from the our website.

 

DrDAQ ph electrode

 

	pH is measured using a standard electrode with a BNC connector. Pico supplies a robust epoxy bodied pH electrode ideal for educational use. It covers the full 0 to 14pH range with a resolution of 0.02pH.
Size	12 x 120mm
Operating temperature	0 to 60°C