[Open_electroporator] Determining resistance before pulsing

Nathan McCorkle nmz787 at gmail.com
Tue Sep 11 16:24:55 UTC 2018


Hi John,
What should be our method for checking the resistance of the sample? I
guess the latest version 0.7 has the lower voltage selectable, other
than the enclosure/box is that all that's changed? Is there some GPIO
that needs toggling to select between 8V (I think that was the lower
voltage) and 18V?

Can we expect things can be relatively unsynchronized, in terms of the
timing for enabling 8V, then turning on either push or pull GPIOs,
which will then allow the 8V through to the coil, which seems like it
would only allow a single pulse through the coil to the "HV" side and
then through the cuvette and load resistor. So I guess timing and
synchrony need a bit of attention, since we can't assume DC on the
low-side will make DC on the high-side.

Maybe this just means I need to start the ADC in single-channel DMA
mode, perform the LV pulse, then do some rough signal processing on
the ADC data... find the peak in the pulse hump, then whatever the
peak value is, we use to reverse-calculate the resistance? (since the
ADC reading from the shunt will be a voltage... I guess I need to
update my GUI to actually convert those readings, which I wasn't doing
before)

-- 
-Nathan


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