Hi Lavaguava! Thanks for the reply. The battery that i'm using is a batterypack to charge a phone, so i guess it operates at 5V. Or 2600mAh*5V=13 watt hours. I'm really amased that the pizero only draws 45ma when idle, because i used a arduino mega 2560 almost the whole time idle on this battery an that lasted 55 hours. The pizero is a lot more powerfull so i assumed that it would consume more but it appears that was a wrong assumption
I know that the arduino can store data in its EEPROM memory, but even for the Mega the memory capacity was too little for my application. (if i store it in the flash memory and the battery dies i lose everything).
When i see your calculations i guess i'm going to go for the pizero, i just love the calculating power (even though i totally do not need it) of this little animal!
PS: would it be hard to implement the pizero on a PCB? (i'll be using Altium)
Ok, the battery looks like it would be suitable, at 13 watt hours, you can expect a little over two days then. Putting in the considerations of potential temperature swing, cell degradation and variable power draw depending on what the Pi is doing, I think you can safely get away with one day. It is a lot more powerful and will use more power accordingly, but when your actual workload does not include the normal things that the Pi zero can be stretched to, the power draw will be significantly lower.
How much data are you planning to store? How much data do you collect each day? How often will the data change? What is the plan with the automation of this thing, including how the battery is charged and how often the data is collected and backed up?
The eeprom may not be a good idea, you can only rewrite it about ~10,000 times on an steel and it becomes unreliable. Depending on the nature of your data collection and storage methods, this lifetime may be used rather quickly. On the other hand you can get an external flash chip or SD card which can be changed out at any time. Alternatively you could utilise cutting edge memory technology:
http://www.digikey.com/product-deta...-inc/MR256A08BYS35R/MR256A08BYS35R-ND/2686866 Non-volatile, unlimited cycling, speed comparable to SRAM, I have wanted to use one of these instructions project since they became unavailable. They are a very good choice if you need to keep on changing data and may suffer a power out at any time. Now that I have a budget that allows, I will be trying MRAM myself.
The Pi zero would be my choice as if you plan on furthering your project, it gives room for improvement and you can easily implement more complex code without worrying about filling up the flash.
It would not be difficult to implement to PCB if you have a bit of practice, I have no experience with Altium, having only used EAGLE a few times. You could either remake the board yourself due to the open source nature, or you could simply purchase the premade board and have a 2*20 0.1 inch pitch block for connecting.
Also take a look at
@OBW0549 's suggestion, this does seem like a sensible choice. I would go with the Pi zero, but I do not really know the nature of your project.
