Either go with the PID if it meets your requirements on programming the temperature profile, or with the BCS brewing controller which certainly does. What I've learned from years of developing electronics: if it already exists as a product, it is likely to be cheaper to buy it than to build it. The time saved can be invested elsewhere. Which doesn't mean building isn't fun, educational etc, but if the product is only a small part of a programme, It's better to get it out of the way and proceed towards the bigger goal. When laying a 10.000 piece puzzle you don't want to make each piece by hand, you just buy them and focus on completing the puzzle. David > Op 30-jun.-2014 om 15:16 heeft Vicente Alvero Zambrano > <vicente_alvero_14@xxxxxxxxxxx> het volgende geschreven: > > Your opinion is to use the existing PID device? > > > Subject: [SS2S-Main] Re: temperature controller with arduino > > From: waaslandwolf@xxxxxxxxx > > Date: Mon, 30 Jun 2014 14:21:03 +0200 > > To: sugarshot@xxxxxxxxxxxxx > > > > I agree with Peter. Trying to save a mere 180$ by developing a solution > > that already exists isn't good use of resources. > > > > > Op 30-jun.-2014 om 00:52 heeft Peter Johansson <rockets4kids@xxxxxxxxx> > > > het volgende geschreven: > > > > > > On Sun, Jun 29, 2014 at 6:36 PM, Vicente Alvero Zambrano > > > <vicente_alvero_14@xxxxxxxxxxx> wrote: > > > > > >> My idea is to use an old oven heater like the picture. > > >> With respect to the PID controller, maybe it is cheaper to do it > > >> manually, > > >> without writing code. > > > > > > One option to consider -- and an advantage to going with a homebrew > > > solution -- is to simply read a configuration file containing the > > > temperature profile and PID tunings over over the serial port. > > > > > > This way you get the maximal possible control with the minimal > > > hardware cost and minimal software development time. > > > > > > -p. > > > > >