<div dir="ltr"><br><br><div class="gmail_quote">On Fri, Oct 17, 2008 at 1:36 AM, Peter Loron <span dir="ltr"><<a href="mailto:peterl@standingwave.org">peterl@standingwave.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d"><br>
On Oct 15, 2008, at 5:04 PM, Yan Seiner wrote:<br>
<br>
><br>
> On Wed, October 15, 2008 4:52 pm, Darrin wrote:<br>
><br>
>> Nice. If it were me, I'd complicate it a bit more and use an atmel<br>
>> avr<br>
>> tiny<br>
>> to do the same thing. Then, you have the ability to reprogram it<br>
>> to your<br>
>> whims and no potentiometers are needed. You could even change the<br>
>> ramp<br>
>> rate<br>
>> on the pwm to be completely non-linear for your specific needs. The<br>
>> ATtiny24<br>
>> could do the job, has an onboard temp sensor, built in PWM, and<br>
>> only costs<br>
>> $1.91 from digi-key.<br>
><br>
> Any chance of doing a project page on this? That could be cool.<br>
><br>
> Even cooler (no pun intended) would be something with a termistor on a<br>
> lead that could be stuffed into a hard drive caddy space. :-)<br>
><br>
> --Yan<br>
><br>
<br>
</div>Should be quite easy to put together...I've got some Arduino boards<br>
kicking around. I'd need to get a leaded temp sensor. Hmmm. I wonder<br>
how expensive it would be to get something together to read K-type<br>
thermocouples.<br>
<br>
-Pete<br>
<div></div></blockquote><div><br>I just ordered parts and picked up a Dallas DS18B20 digital temperature sensor for less than $5 at Sparkfun electronics. You could probably call Dallas and get them to send you a sample if you really want to do it on the cheap. I got it mostly to figure out if it would react any faster or better than the one already on the ATtiny.<br>
<br>Thermocouples would require some added interface circuitry (like the LM741 op-amp) to get a usable signal. The benefit is that they will detect temperature changes more quickly than a packaged silicon device would. I'm sure there's plenty of example circuits already out there on the web that would help if you decide to go this route.<br>
<br>--Darrin<br></div></div><br></div>