IOT Based Temp measurement and control system(ARDUINO NANO FREEZING TEMP)

Hi,
I have made an IOT Based Temperature measurement and control system.
The sensor node consists of an Arduino Nano micro-controller, a radio module (RFM69HCW), and a temperature sensor module (MCP9808).

Sensor node power is supplied by 3 *1.5V batteries and it sends the signal to server node each minute. The temperature of the place is around -30C. The compete system is in a casing to make it waterproof.

The problem is that the sensor node works fine for a week sometimes more sometimes less after that it stops sending signals and every time batteries are drained.

I don't know why batteries are draining so fast. It's because of the low temperature or what?
Every time I take out the batteries there is moisture on them sometimes on Arduino and other devices as well.

Any suggestions to keep it working for more than 3 months.

Condensation may be an issue. Putting warm items in a case, sealing those items in a box, and putting that box in a cold environment… There are steps you can take, search on internet, try the words “ways to stop condensation” in your search.

I have a solar project using one 2600mAh battery. Whiles the battery is recharged by a solar cell there comes times, like when a storm moves in, that recharging does not happen. Using an ESP32 set to deep sleep for one minute, gets about 1.5 days of operations without a recharge. When I switch to a sleep cycle of 5 minutes, I get >4 days/4 nights of device operations, without recharge.

Perhaps a change of sleep wake cycles could provide you with longer time between battery drain?

Nano is not particularly power efficient for battery projects. It has components on board which drain power unnecessarily such as the USB-serial chip. A 3.3V 8MHz pro mini would be a better choice. Or a bare atmega328, which you can easily solder up on a small piece of stripboard. You can use the Nano as an in-circuit programmer for the atmega328. If you have not done this before, it's quite easy. With a bare atmega chip, and low power sleep library, you can get very long battery life, many months at least.

@PaulRB
I used 3.3 8Mhz pro mini, but it just worked for one day and when I took out the sensor the led light next to Arduino reset button was red and struck, I don't know what that represents.
I pressed the reset button and it started working again.

@Idahowalker
I was also planning to use the heating element, but the problem is that I have to put the sensor node in the fridge, and to use a heating element I have to supply power to it but the problem is how I will supply power.
The most heating elements I found operate at 12v.
The casing in which I put the whole setup is not large enough to use a big battery bank

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

What 1.5V batteries are you using?
What is the current drawn by the project?
What battery life are you expecting?

Thanks.. Tom... :slight_smile:

kazmi12:
I used 3.3 8Mhz pro mini, but it just worked for one day and when I took out the sensor the led light next to Arduino reset button was red and struck, I don’t know what that represents.
I pressed the reset button and it started working again.

There is nothing I can think of about Pro Mini that would cause that to happen that would not also happen to a Nano. They have the same MCU chip.

I suggest you investigate the current consumption of each of your components using a multimeter, to find out what is draining the battery. Keep everything at room temperature and measure the current consumed by each one during activity and during sleep periods. Post the results here and we may be able to suggest what can be improved.

TomGeorge:
What battery life are you expecting?

kazmi12:
more than 3 months.

From the RFM69 data sheet:


So the current consumed by the transmitter should be up to 130mA when active and 1uA or less when sleeping.

From the MCP9808 data sheet:


The current should be less than 0.5mA when active and less than 1uA in sleep.

Can you put the MCU OUTSIDE the freezer and run a 4 wire cable to the sensor INSIDE?

This article shows what can be achieved with Pro Mini 3.3V: