EDAQuino tutorial

List of content

download the edaquino.ino file
open the .ino file
connect the Uno board
in the Arduino IDE select the COM port of the board (likely the last element in the list) and the Uno board
click on the Upload button to upload the firmware on the board and wait until it is done

download the edaquino-com.exe
connect the Uno board
select the COM port of the board (likely the last element in the list)
set baud rate to 250000 Bit/s
in the Options there are numerous measurement parameters
- you can choose from different type of sensor outputs
- to measure with a thermistor select Resistance output and in the Scaling part select thermistor to get the proper, exponential scaling
- predefined parameters of a 10k NTC sensor can be used
- you can name the channels and give units to Y axes
you can select channels to display from the toolbar
start the measurement

you can measure different type of sensors with the EDAQuino shield
in Voltage output mode it is able to measure
- simple, GND referenced voltage
- various types of voltage output sensors with calibration (Hall sensor (SS49 is in the video), phototransistor, etc.)
in Resistance output mode you can measure
- simple, resistance of a resistor or variable resistors
- various types of voltage output sensors with calibration (thermistor, photoresistor, potentiometer, etc.)
in Voltage Difference mode you can measure potential difference between B and C channels like:
- non GND referenced voltage (voltage drop on a resistor, induction voltage in a lead loop induced by a moving magnet, etc.)
in Wheatstone bridge mode it is able to measure
- voltages outputs derived from this type of resistance configuration (pressure sensors (MPX2010 is in the video), etc.)

there are some displaying functions in the local menu of the graphs
in Scale menu it is able to set the desired range of the y axe or use the autoscale feature
by clicking on Clear data the previous measured data will be cleared and the time axe will be reset
by clicking on Copy data the previous measured data will be copied on the clipboard and you can paste it for example into an Excel table

in the Options window you can set Scaling parameters that can be derived from the datasheet of the sensor (A is the reciprocal of the sensitivity and B is the negated offset multiplied with A)
to measure the period time of a periodic signal it needs to have a properly chosen level
to detect level crossings it is useful to have certain hysteresis to avoid false detections caused by the noise
the sampling rate of the measurement can be set from 1 to 1000 Hz
the length of the displayed of the signal can be set 1 to 200 sec
after all you can save the parameters of the settings to an .xml file

connect to the EDAQuino shield, the USB cable and the thermistor to the Arduino Uno board
select COM port
in the Options window select resistance output and Thermistor in the Scaling part to get the predefined values of calibration
one can increase the length of displayed signal for slower measurement
digital number display is also available in the toolbar
you can test the thermistor by a cup of hot water

with EDAQuino shield it is easy to measure a common 3-Axis Accelerometer Module for Arduino (we have used one with ADXL335 accelerometer IC)
the settings of this measurement can be seen above in the Advanced settings video
the Y axe of the sensor gives the largest signal therefore the other two channels can be turned off
to determine period time of the movement the level crossing detection is available in the program (see video Advanced settings above)
in this case each second rising edge determine the time of one period

in the Options window select Internal photosensor sensor type at Channel A
select desired Level and Hysteresis for level crossing detection
choose a big enough sample rate and set a Time frame value for the length of the displayed signal
move up and down your finger on the IR LED and phototransistor to check the measurement
put your wrist to the table to your finger can be in a stable position
- do not press your finger down too hard, it results too small signal
the pulse signal appears some seconds later because the input capacitor needs to set to the actual voltage level
you can turn on the level crossing by click on the Level crossing button in the toolbar
the period time of the pulse signal is appear in the right side of the window

to measure the movement of a pendulum it is necessary to set the Level corssing detection parameters
with Level parameter you can set a desired value above what a detection point (black triangles) is taking placed
Hysteresis is useful to avoid false detections caused by the noise
this is realised by two threshold levels and between these no level crossing will be detected if the signal changes its direction
by giving the Object length parameter it is able to measure the speed of a movement of an object (in this case the speed of the swinging pendulum is measured at the photogate and these are the short impulses in the signal)
it is advisable to set the Sampling frequency to a big enough value to avoid the inaccurate measurement of the speed in this case
by clicking on the Level crossing button three columns appear on the right side of the window
- “t” is the time of the rising edges at level crossings
- “dt” is the difference between two adjacent “t” points eg. period time
- “v” is the maximum speed of the weight of the pendulum in the current case

the strength of magnetic induction (B) is measured in Gauss (G) units
the calibration parameters can be calculated from the datasheet of the applied Hall sensor (SS49 is in the video)
by measuring two types of magnets it is noticeable theat the neodimuim magnet ha a stronger magnetic field
by change the display mode to Digital display one can easily read the actual value of the magnetic field at certain points of the magnet

the built in photoplethysmograph part of the EDAQuino shield can be built on a single breadboard without soldering to use as a reflective photogate
Pendulum
- each second level crossings determine one period
- therefore it is advisable to detect each second rising edge because in this way the measurement error derived from the asymmetry of the swinging can be cancelled
Spring
- you can test the sensitivity of the measurement with moving your hand over the sensor in distance
- the signal appears on the graph is easy to detect with a simple level crossing algorithm
- one can detect each rising edge to determine the period time of the movement

Some other tutorial videos will be available soon…