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

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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