Remote fridge temperature sensor

Hi guys,

I have to develop a project where I have to sense the temperature inside a fridge and later, send it to Internet. So I have to choose the components and the best way to implement the solution.

What's the best way to send the temperature to internet? Will I have Wifi signal inside the fridge? I've tried to send a whatsapp to my phone which was inside the fridge and I received but... will it work in any case?

Additionaly, I have to send a message if the power supply of the fridge falls down... so I should use the GSM shield. Will I have 3G signal inside the fridge?

What do you think about it? :D

Thanks,

A.

sensor in the fridge. ALL electronics external.

you can measure temperature and power. of course, you also need to have power for the time of the power fail.

but why stop there ? monitor : -room temp -superheat

this way, you can determine the number of cycles the unit is running per hour. if it cycles too often, then the door could e open, the Freon is low, or someone put in a hot pot of soup without letting it cool on the counter first.

DS18B20 in the fridge, Arduino with ethernet shield outside, connected to Xively, or the like. Presumably this is important enough to merit connection to emergency power, and be able to notify you when that happens.

Dave wrote:

the Freon is low

Freon, really, they still use that stuff in the US then, it's been banned for years.

Australia is still suffering from a large Ozone hole caused by CFCs (chlorofluorocarbon) used in refrigeration systems.

But like Dave says, keep your elecronics external to the fridge.

What accuracy do you need, might depend on the sensor you choose and also are there any logging or alarm requirements you need to think about.


Paul

I understand Americans call HCFCs Freon all the same.

:relaxed:

We have two problems to solve:

  1. Power failure: I was thinking to use the Ethernet Shield as you said... but if we have a power failure is caused by a power cut in the building, we won't be able to use the modem to send the signal to Xively. For that reason I was thinking in the GSM Shield. The other point is, can I use any trigger to monitor a power failure instead using an current sensor?

  2. Sensing: The temperature sensor must be inside the fridge, and the electronics outside... how will I wire the cable? I don't want to make holes or something related. If I have to wire the cable from the sensor inside to outside using the door... will I be able to close it properly?

For me, the best case would be a sensor inside or outside the fridge easy to be installed that can get reliable data.

Any temperature wireless sensor to send signals to the Arduino?

Thanks,

  1. You can operate your device using batteries. You won't need to replace 'm if you add a charger.
  2. There's hardly any power involved, you can use thin wire for you sensors.

Question is whether cable-internet is still working during a power failure, but you could power your router/modem using rechargeable batteries + charger as well.

That's a nice looking sensor for the money. I'd go with that with the ethernet shield and pop a ups on your router. It's handy for when the power goes and you're using your laptop.

TLERDRDEN: 1. Power failure: I was thinking to use the Ethernet Shield as you said... but if we have a power failure is caused by a power cut in the building, we won't be able to use the modem to send the signal to Xively. For that reason I was thinking in the GSM Shield. The other point is, can I use any trigger to monitor a power failure instead using an current sensor?

The GSM shield is powered the same way as the ethernet shield, but is an even greater power-hog.

  1. Sensing: The temperature sensor must be inside the fridge, and the electronics outside... how will I wire the cable? I don't want to make holes or something related. If I have to wire the cable from the sensor inside to outside using the door... will I be able to close it properly?

Clearly, you will have to make a hole.

Any temperature wireless sensor to send signals to the Arduino?

Wrong question. You left out the word "reliable". Same goes for power supply

Nick_Pyner: I understand Americans call HCFCs Freon all the same.

yup. use a Kleenex to wipe my nose put my dishes on the Formica counter-top use Freon 134a in the fridge.....

we also drive on the parkway and park on the driveway

Nick_Pyner: Clearly, you will have to make a hole.

No, no hole necessary. Route the wires (two, probably) on the hinge side of the fridge. Tape them securely. The rubber seal will deform to accommodate them quite easily.

Paul

use Freon 134a in the fridge.....

I think that is pretty much just purified propane. Years ago a person at work told me about recharging the car AC with propane. He said that was what they did in Europe.