voltage drop with bh1750fvi ?
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i create a lightsensor sketch with bh1750fvi, i found when power with CR2032, voltage from 2.9v drop to 2.4 or lower, but bh1750fvi required 2.4V, so sensor node can't continue , but later 3-5 seconds voltage recovery to 2.9v
ATMEGA328P-U-TH+ nrf24l01-smd with Customized PCB, Are there any good suggestions for solving this problem? thanks!
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@huex try with new battery
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@rozpruwacz yes,but new battery also drop 0.4-0.5v like this ,
, this is new battery offer by Two weeks ago.， use it on si7021 node，work well, so 。。。。
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@huex said in voltage drop with bh1750fvi ?:
bh1750fvi
Supply current of this sensor is 190uA, sleep current only 1 uA. Are you sure this sensor is put to sleep when not operating it (when your node is sleeping)?
Are you using a GY-30 module? These seem to have a voltage regulator on board to support 5v supply levels. Try to bypass this regulator when powering from batteries.
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@Yveaux thank you ,
i create a pcb with bh1750fvi chip,
i use multimeter measure bh1750fvi v+ pin and gnd ,when power on battery from 2.9v drop 2.1v ,and 3-5 seconds ,up to 2.9v, use a new battery NANFU cr2032， also 3.1 drop to 2.7v，
sleep all is ok , when sleep 7.3ua
but, when down 2.4v bh1750 no work....so。。。i don't how to do,
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@huex
coincell internal resistance is higher than others batteries.
so when your mcu is not sleeping or waking up, you'll get voltage drop (even a few mA drained by mcu will drop voltage like you noticed)To fix voltage drop and extend lifetime:
- use good brand coincells (significantly better specs and lifetime than nonames)
- add a few(2-3) 100uF close to battery pins for buffering, you can even add one close to the radio module.
- use wait() or sleep() in your sketch before reading your sensor (to allow voltage recover)
- you can also use 1Mhz clock for mcu, to use less power when it's not sleeping
- use a sensor with better voltage range
- and so on..
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@scalz
ok ,thanks , i follow your suggestion to Give it a try，，thank you ,
