Jump to content

Cheap temperature controller


tako

Recommended Posts

I was browsing MPJA and came across this $8 "temperature alarm" that can has the ability to operate an external relay (>80ma draw).

 

http://www.mpja.com/prodinfo.asp?number=5289+RB

 

Who knows how accurate the temperature sensor is, but it's cheap and I have a few SS and mechanical relays sitting around needing a use. I may just try it as a fail safe to prevent a heater from cooking the tank and I may also have it switch on a fan for the hot summer days. Do you see any problems with the plan or have any better options?

Link to comment

Providing that you seal the temperature probe, it should work fine provided it's reliable. What you could do is run a DPDT relay and have the heater on the NC side and the fan on the NO side. That way when the device trips from an overtemp situation, the heater shuts off and the fan turns on.

Link to comment

Nice find. I've been wanting to make something like this until I splurge for a RKL or arduino controller. I was able to find a probe off a heater that had something similar in it. I never liked that heater though because it was really touch and would get stuck on or off if you touched the knob (wiped out a FW tank when it got to about 90°).

 

 

 

I just so happen to have a SSR laying around, if only Radio Shack still sold electronic components :)

Link to comment
Providing that you seal the temperature probe, it should work fine provided it's reliable. What you could do is run a DPDT relay and have the heater on the NC side and the fan on the NO side. That way when the device trips from an overtemp situation, the heater shuts off and the fan turns on.

 

Yep, that's exactly what I had in mind. I think I have a DPDT 110v AC laying around, but just in case anyone else is planning to do this, you can pick up this $3 mechanical relay at the same time:

 

http://www.mpja.com/prodinfo.asp?number=16726+RL

 

would get stuck on or off if you touched the knob (wiped out a FW tank when it got to about 90°).

Yeah, that's my fear. My heater is a little too big for my tank so having a killswitch if it gets stuck will be nice.

 

if only Radio Shack still sold electronic components :)

I used to have the same problem, but now I live near a Fry's. First time I walked in my jaw dropped because of the size of the electronic components section.

Link to comment

I know :angry: Chris took me to Fry's when I first came out there to see the Nanocustoms operation. I couldn't believe it. I'm so jealous.

Link to comment

Archived

This topic is now archived and is closed to further replies.

  • Recommended Discussions

×
×
  • Create New...