EcoRenovator - View Single Post - Arduino controlled "chest freezer" refrigerator

skyl4rk · 10-10-10, 02:23 PM

The relay used was this one:

relays, solenoids, buzzers, timers, sockets & accessories

It is double pole double throw so there are actually two 10 amp relay actuators. Depending on the size of your chest freezer motor, you may want to move up to the 20 amp relay.

A base for this relay is also needed. Make sure that the relay is rated at 6VDC (more or less) so that it kicks in when the arduino turns on the 5V to the trigger circuit. I think my relay was rated at 12VDC, but it still worked. The relay rated at 12V might have used more current than desirable at 5V.

The thermistors were part of a grab bag of thermistors from American Science and Surplus. They do not have them anymore, as far as I can tell. Any thermistor rated at 500 ohm to 1000 ohm should work fine. Just match it with a similar sized resistor. When you calibrate the thermistor you make up for any differences in ohmage.

AS&S did have this: American Science & Surplus : Solenoids and Relays

There was hysterisis built into this code, the code turned the compressor on at Vmax (484 or 4C), and did not turn it off until Vmin (459 or 2C).

I did this project quite a few years ago and had several arduino scripts on an old archive hard drive. I can't tell you for sure if this was the working script, but it should be fairly easy to troubleshoot if it is not the right one, it is a very simple script.

10-10-10, 02:23 PM	#2
skyl4rk Helper EcoRenovator Join Date: Sep 2010 Posts: 66 Thanks: 3 Thanked 6 Times in 4 Posts	The relay used was this one: relays, solenoids, buzzers, timers, sockets & accessories It is double pole double throw so there are actually two 10 amp relay actuators. Depending on the size of your chest freezer motor, you may want to move up to the 20 amp relay. A base for this relay is also needed. Make sure that the relay is rated at 6VDC (more or less) so that it kicks in when the arduino turns on the 5V to the trigger circuit. I think my relay was rated at 12VDC, but it still worked. The relay rated at 12V might have used more current than desirable at 5V. The thermistors were part of a grab bag of thermistors from American Science and Surplus. They do not have them anymore, as far as I can tell. Any thermistor rated at 500 ohm to 1000 ohm should work fine. Just match it with a similar sized resistor. When you calibrate the thermistor you make up for any differences in ohmage. AS&S did have this: American Science & Surplus : Solenoids and Relays There was hysterisis built into this code, the code turned the compressor on at Vmax (484 or 4C), and did not turn it off until Vmin (459 or 2C). I did this project quite a few years ago and had several arduino scripts on an old archive hard drive. I can't tell you for sure if this was the working script, but it should be fairly easy to troubleshoot if it is not the right one, it is a very simple script. Last edited by skyl4rk; 10-10-10 at 02:34 PM..