Hello,
Arduino newbie here respectfully bringing my project here for guidance. I wish I knew how to do this, but need help getting going. Want to make sure I do not go down the wrong path. From watching this site, there is some incredible knowledge here, so am hoping to tap into just a tiny bit of that!
Am building a temperature monitoring system that will use data from one sensor to operate a 1/2 hp 110v electric motor.
Sensors are DS18B20s.
Will monitor temperatures from about a dozen DS18B20s.
Data will go via modified cat6 cable to an Arduino Mega1280. (DS18B20s, time stamp, temp.)
Data from one of the DS18B20 will operate a relay for ½ hp 110v motor.
Data will transfer via ethernet shield from Arduino Mega1280 to Ubuntu/Mint/Debian PC for storage/analysis.
Other sensors will have data read and logged every 30 seconds.
What type of relay works best here?
Regarding the Arduino code, 're-inventing this wheel' makes no sense to me and I learn best using a solid code base to work and learn from.
IMO, having a proven solid code base to start with and then testing / learning / experimenting off of this would be far preferable.
Anybody agree with this? I know I work best starting with a proven thing and using that to learn.
I would be very grateful for any and all suggestions.
terryking228:
Look at: http://goo.gl/lkfoi which is rated 1 HP at 120VAC. Typical 10A rated relays are probably not OK for the startup surge on the motor.
Good link. I agree, a 10A relay would not be good. Even if it worked, I do not believe it would last long as it would be stressed hard.
Now hoping some people have examples of a similar setup with regards to a code base to start from.
Agree that a hefty relay is required. Motors require more amps on startup, I recommend a 20amp relay for good safety margin. In fact, I'll be using a RIB2401b "Relay-inna-box" for my own 1/2 horse motor application. I'll be using DS18B20s too. Haven't started yet though so no code advice, sorry...
Big electric motors typically use something called a 'contactor' rather than a relay. They seem to be fundamentally the same thing (solenoid operated switch) but are presumably optimised for switching high current inductive loads. The ones I looked at were surprisingly expensive. This may be a good reason to keep looking for an ordinary relay and hope you find one that is up to the job, but I can't help thinking that they're probably expensive for a reason.
Hi guys im interested in doing a small scale version of this. Very bare bones, I'm a hardware guy so i have my circuit set up but im trying to find a piece of code to work off. What I plan on is having 1 Ds18b20 set up to trigger a relay at a set temp limit. I have come across some code but most of it is to log the temps.
Could anyone give me some pointers or point me in the right direction?
PeterH:
Big electric motors typically use something called a 'contactor' rather than a relay. They seem to be fundamentally the same thing (solenoid operated switch) but are presumably optimised for switching high current inductive loads.....
Grainger has a helpful PDF entitled "Choosing Relays, Contactors and Motor Starters" and clarified some points for me. here is the link: Redirect Notice
Hope that is helpful. It clarified some stuff for me.
Updates: I have the brick sketch running fine now, I unsure on how to keep the value from the serial port to compare to my limits. Would i use the math library? Sorry for all the questions
