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

[William Beeson]

Logistically how will this work and is this email chain different from the
other one?  I've been pretty swamped with other obligations lately, but am
very interested in this pre-ordering and testing one.

On Mon, Jun 13, 2016 at 1:13 PM, Keoni Gandall <koeng101 at gmail.com> wrote:

> 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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