Posts made by Will Dickson

@acetylcholin

I think the +/-1uA is probably pushing it. I think you would probably want something more like a +/-50 or 100nA range. It is possible to modify the Rodeostat to reduce the current range. We have made modified versions with +/-60nA and +/-100nA ragnes. There are some notes on how to do this in the "hardware/pcbs/teensy_shield/notes" sub-directory of the project repository https://bitbucket.org/iorodeo/potentiostat See the file named "nano_amp_mods.txt". We made two versions the 2nd worked best. The changes were as follows:

1. R5 = 6.04 MOhm, C19 = 10nF capacitor (100nF range)
   Digikey PN: 541-6.04MCCT-ND, and 311-1136-1-ND

2. R6 = 10 MOhm, C20 = 100nF (60nF range)
   Digikey PN: 541-10MAZCT-ND and Digikey 311-1361-1-ND

There is modified firmware available for these ranges you just need to enable the CURRENT_VARIANT_NANO_AMP #define in the in ps_hardware_variant_defs.h and comment out the CURRENT_VARIANT_MICRO_AMP #define. The ps_hardware_variant_defs.h is found in the firmware/libraries/potentiostat/ sub-directory.

@Rlippert

I think darktable would be a reasonable option https://www.darktable.org/

You can find a list of supported cameras here https://www.darktable.org/resources/camera-support/

There is some information of camera tethering here https://www.darktable.org/usermanual/en/tethering_chapter.html

@Sharlow

The current AppImage binary is built for x86-64 whereas the rpi is ARM. So in order to get this to work you will need to rebuild the serialport-bridge AppImage from source for ARM. This can be done on the raspberry pi itself. The source code for the serialport-bridge can be found here https://bitbucket.org/iorodeo/serialport-bridge You should be able to rebuild the package using "npm build". I have tried this, but I think it should work.

@rcbb

I've been working on firmware examples for the new featherwing. Right now all of the examples use circuitpython. I haven't put in an online repository yet. I will do this in over the next few days. I've been pretty pleased with how well circuitpython has worked for this - very easy and quick to program.

Right now all of the firmware examples just stream the data back to the host PC over USB. I am also pretty excited about trying to make some standalone devices which use feathers such as the pygamer https://www.adafruit.com/product/4242 which have a display, battery connection/charging, SD card, etc. The rodeostat featherwing can be plugged directly into the connector on back. It seems super nice for making a battery powered portable device. The pybadge is also interesting https://www.adafruit.com/product/4200. I think both are still available from Digikey.

We should have the featherwing PCBs available in about two or three weeks. There is some uncertainty on when we will receive the PCBs ... not surprisingly.

@rcbb

Yes with the Rodeostat the best way to add BLE is by using one of the expansion headers. This will require some custom modifications to the firmware.

Also, we will have another option available soon. We been working on a featherwing format potentiostat called the Rodeostat Featherwing. You can find some images and the design files here https://bitbucket.org/iorodeo/rodeostat_featherwing/ .

The Rodeostat Featherwing is a really stripped down version of the Rodeostat Potentionstat with a single voltage range from -1.65V to 1.65V and a single current range. We will make several current range variants such as +/-1, 10, 100, and 1000 uA.

You should be able to use the Rodeostat Featherwing with any development board which is compatible with the Adafruit feather Specification https://learn.adafruit.com/adafruit-feather/feather-specification . There are tons of different feather development boards available https://www.adafruit.com/feather and several have BLE built in such as this https://www.adafruit.com/product/4516 and this https://www.adafruit.com/product/3406. So this would be an easy way to make an embedded device with both BLE and a potentiostat.

@bucoloco

Yes, you can connect the +/-15V on the rodeostat to the +/-12V on the multiplexer.

Earlier revisions of the Rodeostat used a +/-15V DC-DC converter to provide the power rails for the op amps on the Rodeostat. Whereas, more recent revisions us a +/-12V DC-DC converter. The multiplexer is labeled to match the more recent versions of the Rodeostat. However, the multiplexer will operate fine on +/-15V.

@UviniDeSilva

No +/- 0.00009uA (90 picoamps) is too low for the Rodeostat to measure.

I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe

This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.

I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.

--Will

I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe

This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.

I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.

--Will

@horseflesh @CaseyWagner

I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe

This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.

I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.

--Will

@aufdenkampe @wiroon @Peteea6 @aufdenkampe

I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe

This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.

I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.

--Will

@aufdenkampe @horseflesh @RRobertson

I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe

This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.

I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.

--Will

@jonathankam

The first thing the software does is send the potentiostat command to get the hardware variant from the device. It looks like this command is failing for some reason. The "json.loads" in the error message makes me think that it is not receiving a proper response to this command from the device. This generally happens when either the teensy has not been programmed with the firmware or if the firmware on the teensy has been overwritten for some reason.

Could you send me the complete set of error messages along with the commands you sent. This will help me diagnose this issue.

@jonathankam

OK. But just as a check. Close Spyder and all ipython consoles that may be running, etc. Close anything the might have an open connection to the device. Then open a command line and run the python script. Do you still get the access denied response?

@jonathankam

Are you trying to run it from the Spyder ipython console? If so you may be creating multiple instances of the serial device object which would be why you are getting the access denied error. A few other users have hit this issue as well. The easiest way to check this is to run the python program in the standard fashion from the command line instead of from inside the ipython REPL. Do you still have this issue when running from the command line?

@jonathankam

Could send me a few more details on your setup and how you are trying to connect to the Rodeostat.

1. What OS are you using? I'm guessing the OS is windows from the "COM" port reference above, but knowing the version of Windows e.g. 7, 10, etc may help me diagnose the issue.

2. Are you using the Python API or the WebApp?

@MartijnE

I can't really help with the arsenic measurement, but I can help you create a Python program for your tests. Could you provide some details regarding the tests you want to perform ?

@LarryD

The get_volt() method returns the current output voltage setting i.e., the value set by the user (perhaps with the set_volt method) for the voltage between the working and reference electrode. Whereas the get_ref_volt() method returns a measurement of the voltage between the working and reference electrode. There is no method to get the voltage between the working electrode and counter electrode.

@scotty

We do not have a DPV test implemented for the Rodeostat yet. This is something we are planning to add in the future. However, there isn't a specific timeline I can give you for adding this test.

Best,
Will

@gbathree

Hi Greg,

I looks like the access permissions had be set to private. I've change it to public. You should be able to download the file now. You can also access the repository here https://bitbucket.org/iorodeo/ph_meter_firmware

--Will