[Open_electroporator] Culture Shock, the open electroporator is a go

[Keoni Gandall]

Looks great! I am excited to test the machine out.

On Mon, Jun 13, 2016 at 2:13 PM, John Griessen <john at industromatic.com>
wrote:

> Thanks to Bryan Bishop I will be developing an electroporator
> as in the attached proposal starting Wednesday, (and a little setting up
> Q&A with suppliers today).  Here's the feature list from the proposal:
>
> Programming will be via  USB device endpoint for serial ports, and
> referencing micropython documentation, plus a quick how-to published on
> kitmatic.com under the product docs section.
>
> Power will be by 28 Volt “wall wart” external UL listed power supply.
>
> Output zaps will be disabled when USB is plugged in – no USB remote
> controlling, (safety reasons).
>
> Programmability of output zaps will be by a sequence of python commands
> that do not guarantee a definite pulse shape.   Pulse shape will have to be
> arrived at by trial and error, using external observations with
> oscilloscopes to a voltage divided down test point that is inherently not
> safe to touch, and the whole oscilloscope is not safe when using it to
> observe the HV discharges. The reason it is not safe is the voltage divider
> chain of resistors could fail conductive-→oscilloscope gets zapped-→people
> touching oscilloscope usually.
>
> Micropython running on a STM32F030CCT6 which costs only $1.30 or
> STM32F401CBU6 which costs $2.8 will power the sequence and control
> functions.
>
> Indicator LEDs and pushbuttons will be provided for Ready, High, Medium
> and Low states of the machine.  The Ready LED will be red or green and when
> red, pushing Ready button “gets it ready” for the next zap.  High, Medium
> and Low  pushbuttons change to different stored zap profiles named  High,
> Medium and Low.
>
> Fire button causes a discharge.
>
> Batt indicator LED is low duty cycle blinking red when battery needs
> charging soon.
>
> Standard electroporation cuvettes with aluminum contacts will be connected
> somehow to the zap output such that high voltage cannot jump a gap to  to
> where the cuvette mounts when a safety guard is removed for loading and
> unloading cuvettes by hands.  The safety guard lid will probably operate
> like a knife switch where contacts, are more than 7mm apart and are bridged
> by a copper strip, (or pogo pins),  when the lid is pushed on.  When the
> lid is open, no bare contacts will have high voltage on them.  Bare metal
> with HV might be present inside a 3mm hole that a pogo pin goes into, or
> inside a 1.5mm insulated slot that a copper strip goes into to make
> contact.  Fingers randomly touching the cuvette area would not touch
> anything but insulator and have an air gap to HV of more than 7mm.
>
> The overall size will be less than 10cm X 10cm X 5cm tall if using
> electroporation cuvettes, and smaller if using pipectrodes.
> local LiFePO4 battery, circuits to charge it,  detect state of charge.
>
> Flyback switching power supply with  flyback 57:1 transformer  to generate
> at least 3kV into a 30kOhm load starting from the low 3.2V of the LiFePO4
> battery, or the 28VDC external power supply.
>
> 28VDC external power supply (from AC 120V). Either/or a 28VDC external
> power supply (from AC 240V).
>
> John Griessen
>
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>
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