Portable Temp and Humidity meter

Hi, first of all I would like to say, that I am n00b, actually never studied electrotechnics.
I did one build with Arduino, but it was just LED strip and thats all.

So I would like to ask you for help me to understand to Arduino and if its even possible to do what I want to do.

Now, I have a build in my mind, but as I said I dont know much about arduino or batteries etc.

Portable Temperature and Humidity meter

Arduino Nano V3.0 ATmega328 16M 5V

Li-ion baterie 2x GEB18650P 3,7 V, 2p 5000 mAh

LCD display HD44780

BME280 Modul

I know how to connect a display, battery and BME280 modul to Arduino and got it working in Tinkercad Circuits.
You can check it trough the link if you want to.

Portable humi/temp TINKERCAD

Now I am struggling on the portable part. I mean, I can carry it because its powering from the battery, but some day I will need to take it and take out battery and charge it.
But I dont want to every time to take out the battery and get it somewhere to charge it. My idea is to take the whole box and charge it trough usb, like by PC or PowerBank.

I know i would need more parts like Linear Usb charger next I think I would need some Charger Shield to not blow up the battery.
I read few pages about charging a battery (making a charger) but I dont know if its the same what i want.

So I dont know if I can even build this, is it possible to charge battery like this ?
I think I would need a swith to turn off a display or even whole Arduino for charging, right ?
Another thing I am curious about is how long it can operate. I read that Arduino can operate moths from a coin battery. I wonder how long I could operate Arduino from 5000mAh batter with LCD display, I have hard time to figure out cunsuption of Arduino and LCD display. Maybe its stupidly obvious, but I dont understand it, but still trying to get it. I saw some SW options for sleep modes with Arduino, that could run for a long time right ?

So now you know my plan and my troubles.
If you have any knowledge you would share with me, please do, or send me somewhere else where I cand find more, like for dummies :slight_smile:

Thank you :slight_smile:

Your choice of components is mostly okey. Personally I use powerbanks, those that can charge telphones, for portable Arduino UNO projects.
The HD 44780 is an excellent choice. I use for I2C-displays. It works fantasticly well.

I like the 5110 nokia display. very lower power.

OP uses a Nano so I don't think low power is a major concern.

Powerbanks are great indeed - built in charger, charge control, 5V boost converter. But they need a minimum load of typically 50-100 mA or they will switch off after some time. Not good if the project has to last as long as possible, that needs a whole different approach.

Something like the Nokia display (it's minimum voltage of 2.7V is a bit high for this - there are LCD displays that work at lower voltages), Pro Mini, BME280 and 2xAA batteries would be my choice for this project.

@wvmarle
About powerbanks, need for 50-100...
That is not correct. I use a timer to pulse an output high into a resistor down to gnd and it makes a single UNO run "for ever", until the power bank is empty. There is a thread here in Forum about it.

OK, that’s another way to make them last. I’ve used power banks either for quick&dirty projects (as long as it works for an hour or two it’s good enough), or where the power draw as such that the minimum draw was not an issue (3-4A continuous).
For anything that needs to operate low power for really long time I’d rather look at a pair of AA batteries and a 3.3V Pro Mini.

wvmarle:
OP uses a Nano so I don't think low power is a major concern.

Powerbanks are great indeed - built in charger, charge control, 5V boost converter. But they need a minimum load of typically 50-100 mA or they will switch off after some time. Not good if the project has to last as long as possible, that needs a whole different approach.

Something like the Nokia display (it's minimum voltage of 2.7V is a bit high for this - there are LCD displays that work at lower voltages), Pro Mini, BME280 and 2xAA batteries would be my choice for this project.

I think the OP said he was a noob and looking for any help.
to me when he said batteries and carrying the thing around, he does not know about ultra low power use and the MINI is a guess.
Alas, he has not re-posted, so we are speculating as well.
the 18650 batteries might work. you can get a charger for dirt cheap that charges with the phone charger.
a small battery case.
of course you could get a multi-battery charger and only use 1 battery and put in your stuff in the other spaces.
I have a 'solar' charger that has a battery. the idea is that if you leave it in direct sun, at the equator, the solar panel will be able to charge it enough to compensate for the loss due to leakage over months. I left in the sun for 2 weeks and got no measurable increase in charge. but the case is promising for a future project.