[Noisebridge-discuss] recommendations for discuss forum - electronics

Frantisek Apfelbeck algoldor at yahoo.com
Fri Aug 17 06:38:38 UTC 2012


Thanks a lot, I will get through that and get back to you both. I'm rather worried about creating too much Noise at the discuss, after all I'm now in Korea so not "physical" part of the community, hopefully I will be able to join the crowd soon, I'm missing the people mostly.

Sincerely,
 
Frantisek Algoldor Apfelbeck


biotechnologist&kvasir and hacker


http://www.frantisekapfelbeck.org


"There is no way to peace, peace is the way." Ghandi



________________________________
 From: Henner Zeller <h.zeller at acm.org>
To: sean.p.cusack at gmail.com 
Cc: Frantisek Apfelbeck <algoldor at yahoo.com>; Noisebridge <noisebridge-discuss at lists.noisebridge.net> 
Sent: Friday, August 17, 2012 3:33 PM
Subject: Re: [Noisebridge-discuss] recommendations for discuss forum - electronics
 
On 16 August 2012 22:37, Sean Cusack <sean.p.cusack at gmail.com> wrote:
> I'd say this forum isn't a bad one :). 1-2 day response time could be
> optimistic or conservative depending on your question!
>
> Do you need the peltier to be able to be heated and cooled? If this is a
> requirement, you want to use an H-bridge instead of a relay. An H-bridge
> will let you flip the polarity of the DC current, thus being able to flip
> which side of your peltier is hot or cold. Also, an H-bridge is a way to
> sort of PWM big power stuff...without the pulsing. So, if you want control
> to be adjustable, you should really use an H-bridge. The relay will just get
> you off or on.

Also, a relais is mechanical, which means (a) it wears out (b) the
clicking will drive you crazy. Unless you get a solid state relay,
that is.

+1 to the H-bridge suggestion if you need heating/cooling.

If you just need one direction, and switching 12V, a FET with a low
Gate-Source voltage will do the job, e.g.
http://www.digikey.com/product-search/en/discrete-semiconductor-products/fets-single/1376381?k=irfz44n
The 'low' Gate Source voltage means that it switches with the ~ 5V of
our Arduino (traditionally, FETs were more happy with voltages around
10V, but these here go down to ~4V).
This solution of course means that you share a ground with both circuits.

Also: if you actually only want heating, no cooling, then you might
consider just a cheap resistive heater, not a peltier element. You can
even operate them on 120V, if you use a solid state relay. That relay
is a bit more expensive (~$20, but you find cheaper ones (~$5) on
eBay), but you save the bulky PSU.

If you want a nice precise temperature control, you might want to
implement a PID controller to quickly reach your temperature and stay
within narrow ranges. But speaking of which, you can directly get
these in a bundle with solid state relays for relatively cheap ( e.g.
http://www.ebay.com/itm/Universal-Digital-PID-Temperature-Controller-TD4-SNR-Solid-state-relay-SSR-40DA-/130697313612?pt=LH_DefaultDomain_0&hash=item1e6e2abd4c#ht_2088wt_1398
) (people use this kind of stuff for sous vide cooking).

(the main problem on asking on this list is that you might get more
answers to your question than you were bargaining for ... :) ).

-h

>
> Hope that helps!
> Sean
>
> On Thu, Aug 16, 2012 at 1:49 AM, Frantisek Apfelbeck <algoldor at yahoo.com>
> wrote:
>>
>> Hi to all,
>> I would like to ask for a recommendations for some discus forum where I
>> can ask questions related to electronics with focus on arduino controlled 5
>> V and higher voltage circuits and sensors. When I encouter some issues I
>> would be hoping to get answers/suggestions preferably within one or two
>> days.
>>
>> I’m quite beginner so I have a lots of questions when I’m building the
>> experimental incubator, so now I’m for example looking for a type of relay
>> which I could directly switch on by arduino (5v DC) and it would be strong
>> enough to switch on off peltier device of +- 100W (power coming from PSU
>> 300W so 12v DC). This is just one of many things which I need to find out
>> and sometimes searching for the solutions by myself takes just ages.
>>
>> Many thanks,
>>
>> Sincerely,
>>
>> Frantisek Algoldor Apfelbeck
>>
>> PS This may be answer to the question but I would rather like to confirm
>> it
>>
>>
>> http://www.amazon.com/AGT-Power-Relay-250VAC-Type/dp/B008G1HLRA/ref=sr_1_1?ie=UTF8&qid=1345106766&sr=8-1&keywords=5v+dc+relay
>>
>> biotechnologist&kvasir and hacker
>>
>>
>> http://www.frantisekapfelbeck.org
>>
>>
>> "There is no way to peace, peace is the way." Ghandi
>>
>> _______________________________________________
>> Noisebridge-discuss mailing list
>> Noisebridge-discuss at lists.noisebridge.net
>> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>>
>
>
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