voltage drop with bh1750fvi ?
huex last edited by
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!
rozpruwacz last edited by
@huex try with new battery
@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 。。。。
@huex said in voltage drop with 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.
@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,
scalz Hardware Contributor last edited by scalz
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..
ok ,thanks , i follow your suggestion to Give it a try，，thank you ,