Battery pack size

I am a complete newbie to Arduino but have chosen a project to put together and have ordered what I need. The project is a portable weather station measuring temperature, humidity and air pressure (air thickness only not altitude). I hope to have it take a reading, once every minute.Which is more than sufficient.

My question is what is the minimum power supply needed to last three days(36hrs) roughly?

I want it to be light as I will be carrying it. Lighter and smaller is better.

Thanks

Arduino Mega
Key shield blue back-light LCD 1602
BME280 sensor

Hutzpah:
I want it to be light as I will be carrying it. Lighter and smaller is better.
...
Arduino Mega

Then why on earth would you want an Arduino Mega?

Hi Paul__B
The Mega is light and small maybe the power pack to run it might not be?
I am new to electronics so am copying another project close to what I am aiming for.

Speak your mind Paul should I be doing it another way?
I have just thrown myself in the deep end.

Any help much appreciated.

Thanks

Hutzpah

Hutzpah:
Arduino Mega
Key shield blue back-light LCD 1602
BME280 sensor

I'm not a big expert here, but I think you should consider the NodeMCU board. It is compatible with Arduino, has a onboard wifi chip and with deepslep and some optional hack on the board it could last more than a few days on batteries (ref: yeoman.com.au ).

My 2 cent.

Bye!

OK, my question was why you would want to use a Mega instead of a UNO.

What you have not described, is what you actually want it to do. Your video illustrates a device that displays the measurements (but I didn't watch it much, got into a whole heap of YouTube stuff :grinning: ) but I doubt you want to look at it every minute for 36 hours, let alone three days. :roll_eyes:

Are you saying you want a data logger? You need a recording medium, such as a SD card.

You do not want it to be running continuously or you are going to need a serious battery - an 8 Ampere-hour SLA battery is neither light nor compact though some lithiums would be a little better. The trick is to have it sleep for 59 seconds and wake to take a reading for one second or less. To do this, you would want a DS3231 RTC to wake it up and you have to remove current-wasting components such as the regulator and pilot LED.

So you probably need a completely different design approach, the button shield does not seem to be all that useful and without it the UNO form factor is not useful.

Without further ado, we need to know what you actually want it to do before advising.

Paul__B great post, I am starting to get the picture.
I agree with “need a completely different design approach”
I failed, I should have gotten some counsel first before jumping in blindly.

What I am trying to achieve is a small light portable device to read and display.

1 Temperature
2 Humidity
3 Barometric pressure

Updated data every one minute when turned on. I will manually turn it on periodically through out the day to check. On a stable winters day I might only have to turn it on a few times.
I have no need for altitude info or data logger only temperature,humidity and pressure.

Thanks