<![CDATA[voltage drop with bh1750fvi ?]]>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!

]]>https://forum.mysensors.org/topic/10035/voltage-drop-with-bh1750fviRSS for NodeTue, 18 Aug 2026 05:35:25 GMTTue, 01 Jan 2019 09:54:51 GMT60<![CDATA[Reply to voltage drop with bh1750fvi ? on Tue, 01 Jan 2019 13:08:23 GMT]]>@scalz
ok ,thanks , i follow your suggestion to Give it a try，，thank you ,:+1:

]]>https://forum.mysensors.org/post/96215https://forum.mysensors.org/post/96215Tue, 01 Jan 2019 13:08:23 GMT<![CDATA[Reply to voltage drop with bh1750fvi ? on Tue, 01 Jan 2019 13:00:49 GMT]]>@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..
]]>https://forum.mysensors.org/post/96214https://forum.mysensors.org/post/96214Tue, 01 Jan 2019 13:00:49 GMT<![CDATA[Reply to voltage drop with bh1750fvi ? on Tue, 01 Jan 2019 12:32:48 GMT]]>@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,

]]>https://forum.mysensors.org/post/96212https://forum.mysensors.org/post/96212Tue, 01 Jan 2019 12:32:48 GMT<![CDATA[Reply to voltage drop with bh1750fvi ? on Tue, 01 Jan 2019 12:11:40 GMT]]>@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.

]]>https://forum.mysensors.org/post/96211https://forum.mysensors.org/post/96211Tue, 01 Jan 2019 12:11:40 GMT<![CDATA[Reply to voltage drop with bh1750fvi ? on Tue, 01 Jan 2019 12:06:25 GMT]]>@rozpruwacz yes,but new battery also drop 0.4-0.5v like this ,:disappointed_relieved: , this is new battery offer by Two weeks ago.， use it on si7021 node，work well, so 。。。。

]]>https://forum.mysensors.org/post/96210https://forum.mysensors.org/post/96210Tue, 01 Jan 2019 12:06:25 GMT<![CDATA[Reply to voltage drop with bh1750fvi ? on Tue, 01 Jan 2019 10:43:13 GMT]]>@huex try with new battery

]]>https://forum.mysensors.org/post/96207https://forum.mysensors.org/post/96207Tue, 01 Jan 2019 10:43:13 GMT