[TIPS] battery powered sensors

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The arduino mini pro can have this voltage. In fact it is the same processor as on the 5V versions, only the CPU runs on a lower frequency.

The most simple solution to power the NRF is with a LDO regulator for example lp2950-33lpe3
I’m not sure if it is possible to power the arduino on a higher voltage then the NRF because they are connected via IO. So probably it is better to have them both on the regulator.

If you want to save battery program the arduino on 1Mhz (see above), removeLEDs and sleep very often

Thank you for your answer

I look the data-sheet of the LP2950 and look further LDO regulators, i found the HT7333 who seems to have a 4uA quiescent current, is it a better choice for the battery application?

What will happen when the LIR battery voltage will drop under the regulator output voltage? For example if the LIR drop to 3.1V will the regulator give something like 3V or nothing?

Is it necessary to desolder the on-board regulator if you don’t use the RAW pin (using directly the Vcc one)?

I remember reading somewhere only the power of the NRF has to be under 3.6V the other pins where 5V tolerant… but I don’t find a confirmation back… Will try, will see

For the moment I don’t success to wake my mini pro more than every 8 seconds. Will search further, must be a way.

I will try to slow down to 1MHz as on this example thank you, but I guess you can have some trouble with all libraries who need time? NRF one isn’t impacted?

I just read about the XC6206P332MR who have 1uA consumption, a second way could to replace the mini pro one with this one? (I don’t know if my fingers are tiny enough ^^)

Well I think 1uA or 4uA won’t make much difference, the self discharging of the battery probably has more influence. Can the battery handle the current peaks needed for the NRF?

@ROUGEXIII said in [TIPS] battery powered sensors:

What will happen when the LIR battery voltage will drop under the regulator output voltage? For example if the LIR drop to 3.1V will the regulator give something like 3V or nothing?

Yes it will follow the input voltage. The drop depends on the load and the regulator.

@ROUGEXIII said in [TIPS] battery powered sensors:

I will try to slow down to 1MHz as on this example thank you, but I guess you can have some trouble with all libraries who need time? NRF one isn’t impacted?

The NRF (mysensors) library works at 1MHz. I only had problems with the DHT library, I couldn’t get that to work at 1MHz. There could be others as well off course.

If you look on the mysensors website there a lot of examples that use sleeping, for longer periods.

What kind of sensor do you want to make?

Hi
I finaly received my USBASP AVR programmer
I successfully set the fuses to run at 1MHZ and to get BOD level to 1.8V
I sucessfully flash the 1MHz bootloader

Unfortunatly I can’t anymore flash with classic programmer through TX/RX + DTR/RST of my mini pro.

avrdude: Version 6.3, compiled on Jan 17 2017 at 11:00:16
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "/home/nous/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino9/etc/avrdude.conf"
         User configuration file is "/home/nous/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/ttyUSB0
         Using Programmer              : arduino
         Overriding Baud Rate          : 9600
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xff
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xff
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0xff
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0xff
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0xff
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0xfb
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0xfb
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0xff
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0xfc
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xff

avrdude done.  Thank you.

Une erreur est survenue lors du transfert du croquis

I can still flash with USBASP AVR programmer but it is less convenient cause I have to unplug my arduino to do this…

Any Idea where it can come from?

I think I have read somewhere that you have to create a new Arduino by edit a common file from the 8MHz mini so that the Arduino IDE knows that you have a 1MHz.

@v1per said in [TIPS] battery powered sensors:

I think I have read somewhere that you have to create a new Arduino by edit a common file from the 8MHz mini so that the Arduino IDE knows that you have a 1MHz.

Thank for answer.

I followed the tuto:

I modified the board file

## Arduino Pro or Pro Mini (3.3V, 1 MHz) w/ ATmega328P [YBT 1.8V]
## ---------------------------------------------------
pro.menu.cpu.1MHzatmega328=ATmega328P (1.8V, 1 MHz)

pro.menu.cpu.1MHzatmega328.upload.maximum_size=30720
pro.menu.cpu.1MHzatmega328.upload.maximum_data_size=2048
pro.menu.cpu.1MHzatmega328.upload.speed=9600

pro.menu.cpu.1MHzatmega328.bootloader.low_fuses=0x62
pro.menu.cpu.1MHzatmega328.bootloader.high_fuses=0xDA
pro.menu.cpu.1MHzatmega328.bootloader.extended_fuses=0xFF
pro.menu.cpu.1MHzatmega328.bootloader.file=atmega/ATmegaBOOT_168_atmega328_pro_1MHz.hex

pro.menu.cpu.1MHzatmega328.build.mcu=atmega328p
pro.menu.cpu.1MHzatmega328.build.f_cpu=1000000L


I created the ATmegaBOOT_168_atmega328_pro_1MHz.hex file and added this data:
:107E0000112484B714BE81FFE6D085E08093810001
:107E100082E08093C00088E18093C10086E0809377
:107E2000C2008CE08093C4008EE0BFD0259A86E02B
:107E300023EC3FEF91E0309385002093840096BBC4
:107E4000B09BFECF1D9AA8958150A9F7EE24FF2480
:107E5000AA24A394B5E0CB2EA1E1BA2EF3E0DF2E45
:107E600098D0813461F495D0082FA5D0023829F13B
:107E7000013811F485E001C083E083D07FC08234F3
:107E800011F484E103C0853419F485E09CD076C0F8
:107E9000853579F47ED0E82EFF247BD0082F10E0C2
:107EA000102F00270E291F29000F111F84D07801E1
:107EB00065C0863521F484E086D080E0DECF84364C
:107EC00009F040C066D065D0082F63D080E0E81686
:107ED00080E7F80618F4F701D7BEE895C0E0D1E0D6
:107EE00058D089930C17E1F7F0E0EF16F0E7FF06A2
:107EF00018F0F701D7BEE8955ED007B600FCFDCFBD
:107F0000A701A0E0B1E02C9130E011968C9111977F
:107F100090E0982F8827822B932B1296FA010C0160
:107F2000A7BEE89511244E5F5F4FF1E0A038BF0770
:107F300051F7F701C7BEE89507B600FCFDCFB7BE05
:107F4000E8951CC0843761F424D023D0082F21D0B9
:107F500032D0F70185917F0114D00150D1F70EC0C6
:107F6000853739F428D08EE10CD085E90AD08FE02E
:107F700084CF813511F488E018D01DD080E101D084
:107F80006FCF982F8091C00085FFFCCF9093C600E3
:107F900008958091C00087FFFCCF8091C00084FDD0
:107FA00001C0A8958091C6000895E0E6F0E098E150
:107FB000908380830895EDDF803219F088E0F5DF4B
:107FC000FFCF84E1DECF1F93182FE3DF1150E9F7D5
:107FD000F2DF1F910895282E80E0E7DFEE27FF27CC
:027FE000099402
:027FFE0000057C
:0400000300007E007B
:00000001FF

I tried this fuse configurations :

avrdude: safemode: Fuses OK (E:FE, H:D4, L:62)
avrdude: safemode: Fuses OK (E:FE, H:DA, L:62)

I have an other problem:
At 3.0 V the arduino start
At 2.5V the arduino start
At 1.8V the arduino don’t start… even if I totally disable the BOD level (avrdude: safemode: Fuses OK (E:FF, H:DA, L:62)

How can I be sure it is running at 1MHz?

@rougexiii said in [TIPS] battery powered sensors:

Unfortunatly I can’t anymore flash with classic programmer through TX/RX + DTR/RST of my mini pro.

I finally found I was doing wrong…
Each time I wrote the bootloader and fuses,I flashed just after the program with the USBASP AVR still connected.
I think doing this was removing the bootloader.
And when I tried to program through serial after this, this wasn’t working anymore.

Anyway my 1.8V supply problem is still here if someone as the answer:

@rougexiii said in [TIPS] battery powered sensors:

I have an other problem:
At 3.0 V the arduino start
At 2.5V the arduino start
At 1.8V the arduino don’t start… even if I totally disable the BOD level (avrdude: safemode: Fuses OK (E:FF, H:DA, L:62)

How can I be sure it is running at 1MHz?

PS: sorry for my english

Edit: Damn! an other noob error… I was testing the arduino by blinking the onboard led… but at 1.8V the current through was unsuffiscient to get the led on…
Need to try to get my bme280 and NRF24L01 at this low voltage now

Hi,
An other question:
Without external crystal it is not possible to get a 2MHz or 4MHz frequencies on the atmega328p right? only 1MHz/8MHz right?