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  • RE: Cannot connect to Rodeostat with web app software

    @James

    That is good to know. I'm not sure what is happening, but maybe there is some compatibility issue with the surface pro3? At the moment I don't have access to a surface pro3 which I can use for testing, however I will try to locate one.

    Are all the ports on the surface pro USB 3 or are some USB 2? The Rodeostat/teensy 3.2 is USB 2, but should work fine on in USB 3 ports as they should be backwards compatible ... but you never know.

    Another thing you could try is maybe putting a USB hub (maybe even a powered hub) between the surface pro and the Rodeostat.

    Best,
    Will

    posted in Rodeostat
  • RE: Cannot connect to Rodeostat with web app software

    @James

    It looks like the device is correct - i.e, the vendor and product IDs for teensy are right (vid=16C0 and pid=0483) However, for some reason it looks like the software is unable to open USB/serial connection to the teensy. The "success": false part of the message is saying that the software is unable to open the device. I'm not sure why this is. Is it possible that some other software already has a connection open to the devices e.g. the Arduino IDE or a program using the Rodeostat's python library?

    posted in Rodeostat
  • RE: Current signals for Dummy Cell not as expected

    Hi, we are currently out of the office but we are back on Monday. We will take a look at your questions and get back to you asap next week.
    Thanks for your patience !

    posted in Rodeostat
  • RE: Illumination intensity

    @bah

    For the LED transilluminator adjusting either voltage or current should work for reducing the intensity. However, I think adjusting the current would be the most effective approach and would give you a bit better control of the intensity. Be careful not to overcurrent the LEDs and they can be damaged.

    posted in Electrophoresis and Gel Imaging
  • RE: Device Isolation and Stability?

    @brad

    Q1.) I tried to run multiple sensors within a single experiment cell (shared buffer solution), but have observed what I think is cross-talk between the devices (particularly when running 2 electrodes for electrodeposition). Are there any issues I'll need to consider here?

    Running multiple Rodeostats in a single cell (shared buffer) would be problematic. This issue is that the Rodeostat (and potentiostats in general) actively control the potential between the working and references electrodes using feedback. So when you have multiple Rodeostats in the same cell these feedback control systems can interfere with each other e.g. when the first Rodeostat adjusts the current sourced by its counter electrode in order to maintain the correct WE to RE potential this will effect the WE to RE potential of the second Rodeostat, and vice versa, etc. I think your best option here would be to isolate the test cells if you can.

    Q2.) I sometimes experience more noise in my experiments. I was thinking about just swapping in larger caps on the TIA but it doesn't seem to happen all the time. Another thought was that the power being supplied by my USB hub might be contributing. Any reason to worry? What's the best way to power the rodeostat externally while using USB for serial comm?

    You might try adding a USB isolator - not too expensive (~$35). Maybe something like this
    https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG

    Q3.) I see the P15, P16 (5/3.3V jumpers) next to the expansion headers as one option. However, I assume I would need to somehow physically disable the USB-provided +5V power away from the board?

    It is possible to externally power the Rodeostat, but doing so requires requires cutting a small trace on the underside of the teensy 3.2. This documented on the PJRC website https://www.pjrc.com/teensy/teensy31.html See the images (further down the page) showing the underside of the teensy 3.0, 3.1 and 3.2. In the upper right corner of the board there is the trace which needs to be cut - there is an arrow which points to the trace and callout the describes cutting in e.g. "Cut to separate VIN from VUSB ... etc.".

    posted in Rodeostat
  • RE: Setup and drivers - windows

    @KarlHaxthausen

    Yes the Rodeostat (and teensy 3.2) should work with windows 7. However, with windows 7 you will need to install a driver for the teensy 3.2. There are two ways to do this.

    1.) You can directly install the serial driver which can be download from here https://www.pjrc.com/teensy/serial_install.exe

    This would be the option you want if you just wish to access the device from the windows 7 computer.

    2.) You can download/install the Arduino IDE and then install the Teensyduino add-on. Instructions for doing this can be found here https://www.pjrc.com/teensy/td_download.html

    This will give you a development environment which will allow you to program the firmware on the teensy and would be the option you want if you wish to customize the firmware on the teensy in some way.

    posted in Rodeostat
  • RE: Anyone at the store?

    @mariana

    Hi Mariana,

    In response to your questions.

    Q. Is Rodeostat ready for use? Do I have to do something to make it operational?

    It is ready to use. The teensy 3.2 on the Rodeostat comes pre-programmed with the potentiostat firmware. Software is available for the host PC in the form of a Python library and a web app.

    Q. What accessories (if any) does one need to work with Rodeostat? (Assume I have reference electrode and some ugly, home made three-electrode cell).

    That should be sufficient. The Rodeostat comes with cables for connecting to the electrodes. It also in includes a 50k dummy cell for testing the device.

    Q. Is the software for Rodeostat paid or free?

    The Rodeostat firmware and software are both open source and free. The source for the firmware and software are available in projects repository on bitbucket here https://bitbucket.org/iorodeo/potentiostat/src The teensy 3.2 comes pre-programmed with the device firmware.

    Q Is this software available for Linux (Debian or Ubuntu/Xubuntu)?

    Yes. There is a Python library and a web app. Both will work on linux

    Python library: http://stuff.iorodeo.com/docs/potentiostat/
    Web App: https://blog.iorodeo.com/rodeostat-software/

    Q. What are Rodeostat current ranges?

    The Rodeostat has four current ranges +/- 1uA, +/-10uA, +/-100uA and +/-1000uA

    Q. What will be the price for delivery of Rodeostat from your store location to my country?

    You can get the price + shipping costs from our online store during the checkout procedure https://iorodeo.com/collections/cheapstat-open-source-potentiostat/products/potentiostat-shield

    Q. If I buy Rodeostat, do I have to pay VAT and customs?

    Yes.

    posted in Online store and Shipping
  • RE: Absurdly high currents in CV

    @xilophant

    You should get the best current measurement by selecting the smallest current range which will encompass your data.

    In this case the sample rate just determines the rate at which samples are collected and sent to the host PC i.e. the time step between samples. So the scan rate (V/s) is independent from the sample rate. The scan rate is set via the 'amplitude' and the 'period' parameters as follows scan rate = 4 x amplitude/period.

    You might be able to reduce the noise by taking advantage of signal averaging. You could do this by sampling at a higher rate (while maintaining the same scan rate) and then lowpass filtering the data. For example you could collect data sampling at 100 - 200Hz. And then after collecting the data lowpass filter the data to reduce the noise - maybe using a zero-phase forward-backward such as filtfilt
    https://docs.scipy.org/doc/scipy-0.18.1/reference/generated/scipy.signal.filtfilt.html
    https://www.mathworks.com/help/signal/ref/filtfilt.html

    posted in Rodeostat
  • RE: Absurdly high currents in CV

    @xilophant

    I'm wondering if it is possible that the CE and RE are being swapped? This could happen if the card orientation is not correct. Could you upload an image or two of your setup including an image card inserted into the electrode adapter?

    posted in Rodeostat
  • RE: Expansion of Rodeostat via Multiplexing

    @jbrenner

    This is a very interesting idea - thanks for sending me a link to the paper. I think this would be a great way to expand the capabilities of the Rodeostat. Perhaps the quickest and cheapest way to try this with the Rodeostat would be be make a little external expansion board which implements the make-before-break multiplexing. The expansion board could connect the Rodeostat's K1 header for the working, counter and reference electrode connections and to the DIO header "P14" for power, ground and digital control signals. I think this would be a pretty easy expansion board to make as there are only a few components required. This way we could test the idea without too much new hardware. I think I will definitely have a go at designing this expansion board. I will send you a schematic when I have something ready.

    posted in Rodeostat