Re: [DIYbio] Re: Electronic requirements for redesign of Arduino PCR thermal cycler

Hmmmmmmmm

"wastes days of their time " .. starting out with the equivalent of
Legos might create a fast model prototype but then wastes more time when
moving from prototype to a more stable build. Requires rebuilding from
scratch. Think longer term. Most likely any kit board is a tool which
will be reused in a new project later which then runs into the typical
obstacles and has to be replaced with a better kit, creating an upgrade
cycle which wastes time. Start out with a solid kit first.

"the community is smaller " .. in fact the Arduino community is a drop
in the bucket, though a vocal and photo-polished one, compared to the
larger design communities using more professional building blocks. Note
"professional design" does not mean complex it only means a little bit
of homework is necessary and maybe less glossy photo's.

"less and more reasonable code" .. the code is in a high level language
so it is likely the same. "copy/paste some ubiquitous code" .. If it
is ubiquitous then there is nothing specific tying it to Arduino anyway.

It is not necessary to defend your use of Arduino in past projects.
Arduino is simply not a good recommendation in 2015 for new designs or
redesigns. If you're building an automobile today you don't need to use
an engine with a hand crank. When you designed the DremelFuge you
considered the design options and settled on an industrialized component
with suitable motor, a Dremel. You might have evaluated shiny plastic
objects from Toys R Us like a kiddie toy blender but you smartly passed
on these as underpowered. Just a little bit of homework up front gives
the design significant legs.

I didn't suggest anything about PIC in this thread either so there is no
need to compare. If you would really like, you can review past opinion
from the 90s on PIClist regarding why college students or more advanced
younger dudes should not start or continue projects with the Basic Stamp
(PIC based) - for same reasons as above: more expensive, typically
under-powered so rapidly outgrown, technology likely later to cause
frustration, though great for high school students and younger, and also
not recommended as the basis for solid designs (i.e.: things which
aspire to be more than toys).


## Jonathan Cline
## jcline@ieee.org
## Mobile: +1-805-617-0223
########################

On 3/24/15 3:30 AM, Cathal Garvey wrote:
> That's all well and good, but putting together a thermal cycler with
> an Arduino requires no shields, less and more reasonable code, and no
> additional equipment (programmers, etcetera) over and above the
> Arduino and USB. It requires an AC solid state relay, LM35 sensor, a
> heat gun and a computer cooling fan.
>
> Telling people to use PICs because they'll save €5 on the cost of the
> chip, even if it wastes days of their time because the community is
> smaller and more techie and purist, is a bit useless. People want to
> get stuff done, and people are rarely without the €5 needed to grab an
> arduino, copy/paste some ubiquitous code, and get stuff done.
>
> On 24/03/15 10:05, Jonathan Cline wrote:
>> It is several x more expensive as a building block, similar to the Lego
>> analogy -- and always needs to add more pieces. It is not for real
>> ("college undergrad level") projects. The household name comes from
>> the marketing push and the plethora of required 3rd party pieces --
>> which makes money for those other companies (including the kit
>> suppliers, like Ada), who also do more marketing, and so on. The
>> lameness of Arduino needing shields which boost business for kit
>> suppliers and make it a well-known product placement in catalogs is no
>> justification for using it in an engineering design. "There's a reason
>> xx is a household name" could apply to many xx's which are similarly
>> worse choices. Unfortunately the projects built with Arduino are also
>> falsely labelled "diy low cost" when in fact they are not at all low
>> cost in comparison and others are also led astray. When a lot of script
>> kiddies talk volumes about a technology, it does not mean the technology
>> is beneficial. A lot of the talk is simply confusion or from lack of
>> education. Technology which works does not get as much verbiage in
>> comparison precisely because it "just works" once the initial learning
>> curve is overcome.
>>
>> The software application which allows cutting & pasting the code you
>> mention into your projects likely works on any number of better hardware
>> kits since it is in a high level language.
>>
>> So I repeat my recommendation and have improved it slightly --
>>
>> Requirement #1:
>> * Sell the Arduino on ebay.
>>
>> ## Jonathan Cline
>> ## jcline@ieee.org
>> ## Mobile: +1-805-617-0223
>> ########################
>>
>> On 3/24/15 1:17 AM, Cathal Garvey wrote:
>>> Arduino is fine and highly productive for beginners compared to PIC
>>> whatevers. There's a reason Arduino is a household name and
>>> PIC-number-number-number-number is not.
>>>
>>> I've built functioning thermal cyclers on Arduinos without issue, and
>>> with easily reasonable code (although I was using a pre-written
>>> finite-state-machine library, the availability of which is just more
>>> reason to use a widely used platform like Arduino).
>>>
>>> On 24/03/15 02:38, Jonathan Cline wrote:
>>>> Requirement #1:
>>>> * Throw away the Arduino.
>>>>
>>>>
>>>> I am going to add to the FAQ:
>>>> "Do not use Arduino for real projects. It is like building an
>>>> automobile out of Legos and then expecting to actually drive it."
>>>>
>>>>
>>>> Also, fyi to Nathan. LM339 is a comparator not an opamp so it is
>>>> not a
>>>> good signal buffer. Use an opamp. See my article in Biocoder #6.
>>>>
>>>>
>>>> ## Jonathan Cline
>>>> ## jcline@ieee.org
>>>> ## Mobile: +1-805-617-0223
>>>> ########################
>>>>
>>>>
>>>> On Wednesday, February 25, 2015 at 4:49:50 AM UTC-8, Andy Morgan
>>>> wrote:
>>>>
>>>>
>>>>
>>>> So, I've slightly redesigned the Arduino PCR thermal cycler
>>>> (http://www.instructables.com/id/Arduino-PCR-thermal-cycler-for-under-85/?ALLSTEPS
>>>>
>>>>
>>>> <http://www.instructables.com/id/Arduino-PCR-thermal-cycler-for-under-85/?ALLSTEPS>)
>>>>
>>>>
>>>> to make it a bit better, by replacing the two wiremound resistors
>>>> (100watts) with a cartridge heater (300watts)
>>>> (http://www.ebay.com.au/itm/Cartridge-Heater-3-8-Diameter-3-2-Length-220VAC-300W-/380898256650?pt=AU_B_I_Electrical_Test_Equipment&hash=item58af4e270a
>>>>
>>>>
>>>> <http://www.ebay.com.au/itm/Cartridge-Heater-3-8-Diameter-3-2-Length-220VAC-300W-/380898256650?pt=AU_B_I_Electrical_Test_Equipment&hash=item58af4e270a>).
>>>>
>>>>
>>>>
>>>>
>>>> But the thing is: I have ZERO experience with electronics, and I
>>>> don't know whether the cartridge heater will require too much
>>>> power
>>>> from the Arduino board or power supply, and all the explanations
>>>> I've found on the internet seem to go WAY over my head.
>>>>
>>>> Does anybody know whether the cartridge heater will work?
>>>>
>>>> Any help would be greatly appreciated.
>>
>

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