Hello
I acquired two sensors LM75, MPU6050 with an ESP-WROOM-32 and 18650 Li-ion 3.7 V battery and started playing with them. And now I'm having a problem with them, when I use an external power supply that's not USB, the led starts blinking and won't stop, and the program also won't run. If I use the USB, it works flawlessly. Anyone could help me with that?
Thanks!!!
Do you think that it might help if you told us what sensors you have, what sketch you are using and posted a schematic showing how your project components are connected together
looks like you are feeding the unregulated battery voltage into the ESP32. If you are using Vin, this may result in the voltage being to LOW. The onboard AMS1117 3.3v requires 4.75v as a minimum according to the datasheet If you are using 3.3v as an input then it is to high and you will fry the board. Best is to use a buck-converter to create 3.3v for the board and not waste anything on the lineair regulator. An MT3608 would work.
Thanks for the post. I am new to this project.
The ESP32 does not have a Vin pin. It has one 3V3 pin and one 5V pin. I have connected the positive of the battery to 3V3 pin of the board and the battery is 3.7V. How should I regulate it?
If the battery is 3.7v it's flat. Full level is 4.2v which is way to much for the ESP.
You should use a buck-converter. I use MT3608 with some external parts, they are available as pre-assembled units, but then the minimum output voltage is 5v, which means that you would have to modify it a tad to get to the 3.3v target. like this one
check the datasheet for the output voltage calculation Vout = Vref * (1 + R1 / R2)
With Vref at 0.6, we get 3.3v / 0.6 = 5.5v = (1 + R1 / R2)
therefore R1 / R2 = 4.5. These units have a fixed value for R2, which you may need to modify.
Can you show us what type of board you have ?
I have the same. the pin in the bottom left corner is marked 'v5' and can be used as a Vin pin directly connecting to the AMs1117 3.3 onboard regulator's Input.
Alright, but what do you mean by AMs1117 onboard regulator input?
do you see that part (in SOT 223-3 package) just above the RST button ? That is an AMS1117 (3.3v in this case) voltage regulator.
Alright, will try these steps and get back to you.
@Deva_Rishi when I am using it with only one sensor it works fine. But not with both sensors. why is that?
dunno, it shouldn't be working at all when you power it through the Vin pin, and it should break when you power it through the 3.3v pin. When you power it properly, it should work, I don't really care why it 'sort of works' for now.
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