MySensors power consumption
-
@dopustko said:
@daulagari I'm using http://www.ebay.com/itm/231083181020 and MOSFET transistor as switch connected to DO pin. But this is not ideal solution for temp/hum measurement. It's better to use low voltage sensor for example HTU21T which can be connected directly to 2 AA batteries. It's just proof of concept for other sensors which require minimum 3,3V.
@jonnyfishman my sleep consumption is about 6uA (not mA).You end up getting way out of the maximum operating voltage on the atmel
from page 299 in link datasheet
Voltage on any Pin except RESET
with respect to Ground . . . . . . . . . .-0.5V to VCC+0.5VSo in theory, if your battery is down to 1.8V (which the 328p is specified to be able to run down to), maximum allowed voltage on ANY pin is only 2.3V. When you power up the sensors, they are running on 3.3V. It might work, but it also might be fatal to the atmel chip.
Another issue is that the voltage for a logical 1, might be below the threshold of the sensors input, to detect a logical 1. From the datasheet, output HIGH level could be as low as 2.3V, when running on 3V, if you then lower VCC it also lowers the HIGH level. For the DS18b20 minimym level for logical HIGH is 2.2V, when running on local power (if using parasitic power it's 3V).
/ Thomas
@tbowmo I know for this Atmel limitation. But DHT22 sensor is open collector output and pull up resistor is connected to battery. It can happened that after battery voltage drops the sensor will stop working because of threshold value for 1 as you said. But as I said this was just experimental solution I will use HTU21T sensor.
-
Wow 6uA. That's were I'm hoping to get to.
Running higher with everything disconnected as its not going into sleep mode (no transciever detected). I don't know whether it's a nano clone that's causing the higher consumption and don't want to have to pull apart my Gravitech nano gateway atm.
Will reducing the clock speed have an effect on consumption and how is this best done through the Arduino software.
I've attached my sketch, don't think there's anything in it that would obviously contribute to the load.
MTB.inoThanks.
-
Wow 6uA. That's were I'm hoping to get to.
Running higher with everything disconnected as its not going into sleep mode (no transciever detected). I don't know whether it's a nano clone that's causing the higher consumption and don't want to have to pull apart my Gravitech nano gateway atm.
Will reducing the clock speed have an effect on consumption and how is this best done through the Arduino software.
I've attached my sketch, don't think there's anything in it that would obviously contribute to the load.
MTB.inoThanks.
@jonnyfishman I'm using striped (no regulator and no power LED) version of Arduino pro mini. 6uA is in sleep mode (only WD is enabled). You can simply put Arduino in sleep mde with gw.powerDown(); or gw.sleep(); . Lower frequency means only that current consumption is lower when Arduino is running and not in sleep mode. Lower frequency also mean that Arduino can run at lower voltage.
Try with simple sketch which use only gw.begin and gw.sleep and measure current. -
The nano has some drain for the USB interface chip and PS. That may be where the extra current goes in sleep mode. You may need to disable that, or switch to a different Arduino.
The clock speed when powered up may not be very important if you sleep most of the time and only power up briefly. It depends on the ratios (on time: sleep time and on power:sleep power).
(For some applications, it's better to use full speed when powered up in order to get things done faster to power down sooner; but if your active cycle mostly waits on a slow sensor or on the radio anyway, a slow MCU clock may allow completing the powerup cycle about as soon as a fast clock, in which case the slower clock would at worst not hurt and may help some. You'd have to be sure when using a new library that it fully adapts to the slower clock speed)
-
@daulagari I'm using http://www.ebay.com/itm/231083181020 and MOSFET transistor as switch connected to DO pin. But this is not ideal solution for temp/hum measurement. It's better to use low voltage sensor for example HTU21T which can be connected directly to 2 AA batteries. It's just proof of concept for other sensors which require minimum 3,3V.
@jonnyfishman my sleep consumption is about 6uA (not mA).@dopustko said:
@daulagari I'm using http://www.ebay.com/itm/231083181020 and MOSFET transistor as switch connected to DO pin.
How are you connecting the MOSFET to the boost regulator?
-
Do you know a good source for HTU-21T?
I find some sources for HTU-21D (http://www.findchips.com/search/htu21) the ones that are not out of stock and sell small quantities tend to be pricey and/or have a large shipping charge.
-
Do you know a good source for HTU-21T?
I find some sources for HTU-21D (http://www.findchips.com/search/htu21) the ones that are not out of stock and sell small quantities tend to be pricey and/or have a large shipping charge.
@Zeph lowering frequency can increase power consumption because of slower execution, but it also mean that you can use lower voltage (direct battery connection and no step up regulator).
I'm using P channel MOSFET SI2333DDS-T1-GE3. It has low internal resistance G is conencted to Arduino DO, S to 3.3 V and D to switch regulator.
I got my HTI21T on ebay. -
Hi.
I read last post .. and don't understand something ..
If use ATmega328P version with internal 8Mhz or 1Mhz(if divide) then you can connect directly 2xAA or 2x AAA cell .. its total 3V ..
and THI21T is sensor that working from 1.5V to 3.6V .. then you don't need step up converter..
I make my self sensor with ATmega328P , run on 8Mhz internal RC oscillator , to TIMER2 I connect 32kHz crystal .
I measure VBAT by divider 1M and 390K with 1.1 internal reference and temperature with NTC 10k sensor as divider 10k and NTC sensor ..
I use free MCU pin to controll temperature divider for lower power consumption.. my consumption is 10uA with TIMER2 working and WDG enable .regards
-
Hi.
I read last post .. and don't understand something ..
If use ATmega328P version with internal 8Mhz or 1Mhz(if divide) then you can connect directly 2xAA or 2x AAA cell .. its total 3V ..
and THI21T is sensor that working from 1.5V to 3.6V .. then you don't need step up converter..
I make my self sensor with ATmega328P , run on 8Mhz internal RC oscillator , to TIMER2 I connect 32kHz crystal .
I measure VBAT by divider 1M and 390K with 1.1 internal reference and temperature with NTC 10k sensor as divider 10k and NTC sensor ..
I use free MCU pin to controll temperature divider for lower power consumption.. my consumption is 10uA with TIMER2 working and WDG enable .regards
-
@dzairo You need step up regulator if you use DHT22. If you use HTU21T you do not need step up regulator if you use 2 AA batteries. In second case will batteries last much longer than in first case.
@dopustko said:
@dzairo You need step up regulator if you use DHT22. If you use HTU21T you do not need step up regulator if you use 2 AA batteries. In second case will batteries last much longer than in first case.
sorry... my mistake .. DHT22 is different like HTU22T .. sorry..
-
@daulagari and @dzairo
You wrote about consumptions of 6uA and 10uA. I know that i can reach down to 1uA (or 10uA) with 3V, intRC, timer2 and ext 32kHz. Not clear for me is the consumption and the mode of the nrf24. Is this current included in your setup and do you disable the radio bei switching off the power of the module ? -Pit -
hi. this power consumption is when radio is in power down , on mcu working only timer2 as rtc and watch dog .. if don't need watch dog then can disable and you will have less power consumption.. but I don't know if have bigger consumption watch dog or timer2 .. depend what you need ..
