Hi James,
I would recommend running the cyclic voltammetry experiment from 0.1 V to 1.0 V, at 50 mV/s for a few cycles (3-4 should be plenty). That would be a direct comparison to the experiment I described.
Let me know how that experiment works and we can go from there.
Jo

@ellajonshon76

Could explain in a little detail what you installed. I can't think of any relationship between the colorimeter software and iTunes ... so I'm guessing this error might be and unrelated issue.

I think I have fixed my problem but now I am getting serial exception with error messages that say that my access is denied?

Hi Jonas,
The colorimeter footprint is 15 cm x 9 cm. Height of the assembled colorimeter is 5.8 cm tall (or 6.2 cm with the rubber feet).
Hope that helps. Let us know if you have any other questions.
Thanks !

Hi, yes, for a second order, just place a new order on the online store. We would ship a new order in 2-3 days.

Hi horseflesh,
So, yes, you do need to do a calibration each time you start a new measurement.

The calibration measures the light intensity that reaches the sensor after passing through the cuvette and your blank sample -- which should not be absorbing any light due to the substance you are measuring e.g. nitrate.

The calibration is used as a reference when calculating the transmittance of light through your actual sample.

For the API nitrate test, a 'blank' sample would be 5 mL of distilled water (zero nitrate) developed with the test kit i.e. 10 drops of bottle 1, 10 drops of bottle 2. The color should be yellow like the image shown below. You would pour some of this into a cuvette and calibrate the colorimeter.

I hope that helps !
Jo

This is very interesting. Thank you for posting !

@Will-Dickson I am having the same problem mentioned here and I get the same error and do not see LEDs flash when I try to calibrate with the slider open.

I just got started and got bit by this too. Do you have a new exe yet?

I will install Python and figure out the dependencies if I have to.

Hi Ondrej,
Yes, you can contact us directly at our email address:

jo@iorodeo.com for general Rodeostat sales questions (quotes etc)

will@iorodeo.com for Rodeostat technical questions.

Thanks !
Jo

@chwang

If you are on windows you can use Device Manager. Start with the colorimeter arduino unconnected. Open Device Manager. Then connect the arduino. After the arduino is connect in you should see a new device appear in the Device Manager. If you click on it you should be able to get the com port number.

On linux you can look in the /dev directory e.g. run "ls /dev/ttyACM*" the colorimeter should show up as /dev/ttyACM0, /dev/ttyACM1, ... etc.

Nice catch - thanks for posting this. I've fixed the issue and pushed latest version to the repository on bitbucket.

Thanks for your answer! I am not happy with it, but thank you.

@robotsandi

In this case we are measuring the frequency of the pulses coming from the light sensor. The frequency of the pulses produced by the sensor is proportional to the light intensity. The pulses have a 50% duty cycle - so the pulses are high 50% of the time and low 50% of the time. The dt value returned from the pulseIn function on line 34 of ColorSensor.cpp

dt = pulseIn(FO, HIGH, pulseInWait);

returns the time the pulse is high in microseconds. The period the pulses coming from the sensor (in microseconds) is then 2*dt. This comes from the fact that we have a 50% duty cycle - i.e. one full cycle consists of the pulse being high for dt (us) and then low for dt (us). So we have period_us = 2*dt. To convert the period to seconds we divide by 1,000,000 which gives period_s = period_us/1000000. Replacing period_us with 2*dt we get the period in seconds as period_s = (2*dt)/1000000 = dt/500000. Finally, we want the frequency (in Hz) which is freq _hz = 1/period_s = (2*dt)/1000000 = 500000/dt.

@Will-Dickson
Thank you very much.

@Will-Dickson

Thank you so much! We tried rebooting it before with the potentiostat.ino file; however, we had set CPU speed to 96 MHz and Optimize to "FASTER". It is now working with the settings you specified. Thank you again.

@aster123

It is possible to redirect the serial output. You would need to make minor modifications to the firmware. I think this would primarily involve changing "Serial" in SerialReceiver.cpp and SerialHandler.cpp to the new serial port. The Uno only has one hardware serial port (pins 0 and 1) which is used for USB serial, but you could use SoftwareSerial (https://www.arduino.cc/en/Reference/softwareSerial) to make any two digital pins into a serial port.