Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

User avatar
By aphlox
#95712 Hello,

I am trying to run a ESP-01 with a PIR sensor powered by an 18650 3.7 V battery

I have used:
  • HT7133-1 LDO regulator 3.3V
  • 1000uF 10V Capasitor
  • 100nF Ceramic Capasitor
As in the sketch below.

When the switch is off voltage is stable at 3.3V but as soon as I turn on the ESP-01 voltage starts to drop gradually to around 1.5 volts and ESP switches off. I am not experienced I could use any help thanks in advance.

Last edited by aphlox on Fri Jan 06, 2023 2:40 am, edited 1 time in total.
User avatar
By aphlox
davydnorris wrote:What PIR sensor are you using? I suspect that is the culprit.

Also where is your negative/GND power supply connection? Nothing seems to be going to the negative/GND power rails from the LDO

I am using HC-SR501. But even if I disconnect the PIR sensor ESP-01's voltage still drops.

Ground connection is there I forgot to draw it I updated the skecth.
User avatar
By davydnorris
#95736 Does the ESP-01 board have a LED? Is it on when you turn on the switch?

Would be really good to see the current draw - can you wire a multimeter into the circuit?

Also what is your sketch doing? If you have the wifi turned on then the current draw is quite high