Sudden extreme battery drain [SOLVED]

[Strixx]

@gohan Well. I could try that. But it sounds strange to me that it will all the sudden change behavior. It was running fine without battery drain for a couple of weeks, and then all the sudden started draining the batteries.

[gohan]

I had a pro mini running fine for months in my outdoor solar sensor but I had to replace it as it was no longer working, with led flashing all the time. Later I managed to recover it by replashing bootloader and sketch again.

[Strixx]

@gohan Ok. Then I will try your suggestion. I will first have to learn how to replace the bootloader.. :-)

[bjacobse]

@strixx
Yes please try to update the bootloader first- I think it's quite interesting for the rest of us what is the actual rootcause
I don't use the stock bootlader in any Arduino codes, but instead an optiboot from GertSanders (as optiboot have enabled the WTD/watchdog)
https://forum.mysensors.org/topic/3261/various-bootloader-files-based-on-optiboot-6-2

[Strixx]

@bjacobse So it's time for a new raid with this project. I have been trying to read up on how to change bootloader. And if I understand it correct I need a programmer. And I only have a FTDI for uploading my code to my arduinos.
But somewhere I found that I can use a Arduino Uno instead.

So is this correct? If I buy a Uno will I be able to change to the new bootloader?

[mfalkvidd]

@strixx you can use almost any Arduino. Instructions are available at https://www.arduino.cc/en/Tutorial/ArduinoISP

[Strixx]

@mfalkvidd Thanks! Don't think I found that page before. Found a lot of pages about this subject but not this page. But if I understand it correct I still need to buy a new Arduino. I only have a big supply of Pro Minis. No other models.

[mfalkvidd]

@strixx a Pro Mini should work. It has the same mcu (atmega328) as the Uno, and pins 10-13 are available.

[Strixx]

So I have been reading up alot. And yesterday I finally managed to upload a new bootloader to this ProMini. It was the optiboot that @bjacobse linked to. All worked fine without any errors.

But I must have been doing something wrong, because I am not able to upload any sketch to the Arduino after that. I only get not in sync errors.

Unfortunately I don't have time to continue on this until late next week...

[Yveaux]

@strixx make sure you flash the correct bootloader for the crystal frequency of your pro mini (3.3V 8Mhz vs 5V 16MHz) and select the correct pro mini target in the Arduino IDE. Any errors will cause baudrate deviation in the serial bootloader communication, causing sync errors.