Why doesn't someone engineer a simple _____?

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John Griessen

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Aug 21, 2014, 11:51:54 AM8/21/14
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On 08/21/2014 02:13 AM, David Murphy wrote:> "I've even made one myself, but it's ugly, and it sucks. Why doesn't someone engineer
a simple circuit with a heating element, a
> box, and a temperature controller and sell it for $100 or $200 dollars? I'd buy it tomorrow when I get payed. "

I've asked about signing up to buy equipment like that here on this list and gotten
a lot of silence before. It may be because there are not enough buyers on this list.
Finding the buyers is a tough thing. Scientists can be very focused and even
though they'd like some better bang per buck in lab gear, they don't seem to spend much time
on it. Scientists often say, "Oh, that's trivial..." as an excuse not to spend time on it.

Prove me wrong and work out lists of features you all would like to buy. Then there's that comment,
"tomorrow -- when I get paid", that seems to be about a low budget.
There seem to be very few on this list with much of a spending budget.
Development for small budget scientists will probably need kickstarter.com
both to promote and to collect money to make batches of anything.

David Murphy

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Aug 21, 2014, 12:27:06 PM8/21/14
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actually I was quoting someone else there. 

I was the one pointing to a cheap temperature controlled lizard terrarium and asking if it would suit his needs. 

As with many things: if you want something specialist it'll tend to be expensive. if you want something stamped out by the million it can be remarkably cheap. 




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Patrik D'haeseleer

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Aug 22, 2014, 3:16:06 AM8/22/14
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Yeah - or just google "DIY incubator". Tons of designs out there, usually including a portable cooler, a heat source (light bulb or heating pad), and a simple thermostat circuit. Heck, there's plenty of small academic labs using DIY incubators as well...

Patrik


On Thursday, August 21, 2014 9:27:06 AM UTC-7, David wrote:
actually I was quoting someone else there. 

I was the one pointing to a cheap temperature controlled lizard terrarium and asking if it would suit his needs. 

As with many things: if you want something specialist it'll tend to be expensive. if you want something stamped out by the million it can be remarkably cheap. 
On Thu, Aug 21, 2014 at 4:51 PM, John Griessen <jo...@industromatic.com> wrote:
On 08/21/2014 02:13 AM, David Murphy wrote:> "I've even made one myself, but it's ugly, and it sucks. Why doesn't someone engineer a simple circuit with a heating element, a
> box, and a temperature controller and sell it for $100 or $200 dollars?  I'd buy it tomorrow when I get payed. "

I've asked about signing up to buy equipment like that here on this list and gotten
a lot of silence before.  It may be because there are not enough buyers on this list.
Finding the buyers is a tough thing.  Scientists can be very focused and even
though they'd like some better bang per buck in lab gear, they don't seem to spend much time
on it.  Scientists often say, "Oh, that's trivial..." as an excuse not to spend time on it.

Prove me wrong and work out lists of features you all would like to buy.  Then there's that comment,
"tomorrow -- when I get paid", that seems to be about a low budget.
There seem to be very few on this list with much of a spending budget.
Development for small budget scientists will probably need kickstarter.com
both to promote and to collect money to make batches of anything.


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Jonathan Cline

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Aug 22, 2014, 8:55:24 PM8/22/14
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Light bulb PCR thermocycler/incubator has been discussed here before.  Cathal built one and shared pics.   The unfortunate aspect of this group is that somewhere along the line the builder decides "Oh, I'll use an Arduino" and it starts being more expensive and complex than needed.    So the real answer to "Why doesn't someone engineer a simple ____" is because the group in general has not performed good requirements analysis as needed for a minimal design to end up with something "simple".


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On Friday, August 22, 2014 12:16:06 AM UTC-7, Patrik D'haeseleer wrote:
Yeah - or just google "DIY incubator". Tons of designs out there, usually including a portable cooler, a heat source (light bulb or heating pad), and a simple thermostat circuit. Heck, there's plenty of small academic labs using DIY incubators as well...

Patrik

On Thursday, August 21, 2014 9:27:06 AM UTC-7, David wrote:
actually I was quoting someone else there. 

I was the one pointing to a cheap temperature controlled lizard terrarium and asking if it would suit his needs. 

As with many things: if you want something specialist it'll tend to be expensive. if you want something stamped out by the million it can be remarkably cheap. 
On Thu, Aug 21, 2014 at 4:51 PM, John Griessen <jo...@industromatic.com> wrote:
On 08/21/2014 02:13 AM, David Murphy wrote:> "I've even made one myself, but it's ugly, and it sucks. Why doesn't someone engineer a simple circuit with a heating element, a
> box, and a temperature controller and sell it for $100 or $200 dollars?  I'd buy it tomorrow when I get payed. "

I've asked about signing up to buy equipment like that here on this list and gotten
a lot of silence before.  It may be because there are not enough buyers on this list.
Finding the buyers is a tough thing.  Scientists can be very focused and even
though they'd like some better bang per buck in lab gear, they don't seem to spend much time
on it.  Scientists often say, "Oh, that's trivial..." as an excuse not to spend time on it.

Prove me wrong and work out lists of features you all would like to buy.  Then there's that comment,
"tomorrow -- when I get paid", that seems to be about a low budget.
There seem to be very few on this list with much of a spending budget.
Development for small budget scientists will probably need kickstarter.com - tracked

both to promote and to collect money to make batches of anything.


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Learn more at www.diybio.org - tracked

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Avery louie

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Aug 22, 2014, 9:25:40 PM8/22/14
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As an engineer who builds these kinds of things, my answer is that building something simple especially in low volumes is very difficult.  A lot of people fall into the trap of thinking "hey, I can buy an android phone for $300 bucks, why cant I buy a pcr machine?".  Mostly it has to do with scale, and expectations.

A PCR machine is easy to build, in quantity one, if you are an engineer/scientist/etc.  Especially if you have an epic cruft stash, like I do.  Now scaling that to 100 units, and making it look good is hard.  Who is going to screw them together? package them?  Even passing that knowledge on to someone else so they can build their own is hard.

Just my two cents here.

--A


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Jonathan Cline

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Aug 23, 2014, 11:10:50 AM8/23/14
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Scale and volume manufacturing benefit components which follow Moore's Law, like transistors, and designs that use low voltages like USB.  Power electronics are not on that curve.  A 1500W heating element or a peltier junction are the same now as they were years ago, while an iPhone in someone's pocket today is faster than a 1990's desktop minicomputer.



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Avery louie

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Aug 23, 2014, 12:07:06 PM8/23/14
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Exactly- meaning people expect a lot more.  The same goes for CNC-ed parts, like heater blocks.  Cast, they would be cheap per unit, but it is hard to get get the volume to justify getting a mold made.

--A


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Patrik D'haeseleer

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Aug 24, 2014, 2:47:46 AM8/24/14
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On Saturday, August 23, 2014 9:07:06 AM UTC-7, Avery wrote:
Exactly- meaning people expect a lot more.  The same goes for CNC-ed parts, like heater blocks.  Cast, they would be cheap per unit, but it is hard to get get the volume to justify getting a mold made.

Field's metal (named after Simon here!) melts at 62 °C (144 °F). Why don't we just suspend PCR tubes in a puddle of liquid metal, mounted directly on top of a Petier cooler? No CNC required, and you'd get zero air gap.

Field's metal is a bit pricey because of its high Indium content, but there are some other low-melt alloys that are much cheaper.  This non-toxic Bismuth/Tin alloy melts at 138 °C (281 °F), not much above autoclaving temperature. You may be able to mold a PCR heater block by simply sticking PCR tubes into the molten metal.

Patrik

John Griessen

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Aug 24, 2014, 10:32:12 AM8/24/14
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On 08/24/2014 01:47 AM, Patrik D'haeseleer wrote:
> This non-toxic Bismuth/Tin alloy <http://www.rotometals.com/product-p/lowmeltingpoint281alloy.htm> meltsat 138 °C (281 °F), not
> much above autoclaving temperature. You may be able to mold a PCR heater block by simply sticking PCR tubes into the molten metal.

The huge thermal lag caused by a large mass is undesirable. It just drives up
the Wattage of heaters required, makes parts more expensive, sends more waste heat into the room.

Rapidly transferring heat to the vials one uses is what is wanted. That can be done
with low mass -- heaters inclose proximity to the vials -- individually wrapped,
or a flowing medium swirling around the tubes and no need for any other intermediate
that is solid. Air or liquid heat transfer is best. Air is the simplest fluid to
deal with -- no need for cleanup, wipe off, or problem of spreading around of heat transfer fluid.

Jonathan Cline

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Aug 24, 2014, 11:51:21 AM8/24/14
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Presumably contamination is the problem with placing tubes in anything
liquid. Otherwise just pump in pre-heated or pre-cooled mineral oil as
a bath and drain when the ramp is complete. Or as a similar mechanical
system, pour in/out pre-heated or pre-cooled lead-iron buckshot.
Mechanical systems though are typically larger, heavier, more unwieldy
than electronic systems.

I'll admit though that I've long thought about a simple cooling ramp
using ice water and a thermo-sensor controlled pump. Ice is free.

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Dakota Hamill

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Aug 24, 2014, 1:31:02 PM8/24/14
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Is it seriously named after Simon?  How did you go about creating it?  That's cool...


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Simon Quellen Field

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Aug 24, 2014, 4:40:27 PM8/24/14
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Yes, I invented it.
I sell science toys, so I needed a non-toxic replacement for Wood's Metal.
It was just luck that the melting point came in even lower than Wood's Metal.

I then gave the formula to my metals supplier, so I could have them do the measuring and mixing,
saving me the trouble. They decided to carry it in their catalog, and used my name.


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Forrest Flanagan

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Aug 24, 2014, 7:52:51 PM8/24/14
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For just a good lab Thermostat, my friend Wes and I developed a little circuit with adjustable hysteresis made out of cheap analog components that's very precise and repeatable over a wide temperature range. If there's interest, I can CAD up a board for the thing with a relay for things like controlling heating elements and coolers.

I just calibrate them with a multimeter, anything that'll read resistance will work.

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