I'm thinking of a sensor. I bought all 3.3v materials. The problem is that the lithium battery is 3.7v (I am thinking of using a commercial auxiliary battery). Is there a suitable regulator that is small enough to carry out this voltage drop?
Thank you so much for reading. Looking forward someone reply.
P.s There are also additional questions regarding the vacuum pump on the right side in the figure. It is very necessary to supply the sensor with the proper flow rate. Therefore, if you know a small vacuum pump with a small size and a performance of about 1 L / min, please reply.
I use a single LiPo cell to power a model train that uses an Attiny and an nRF24L01+ wireless transceiver. The max voltage permitted on the nRF24 power pin is 3.6v so I pass power to it via a small diode. The voltage drop in the diode is sufficient to protect the nRF24. (Be aware that a fully charged LiPo will have a voltage of about 4.2v)
In my example there is no need to power the Attiny through the diode as the nRF24 data pins are 5v tolerant. But the Attiny could be powered through the diode if needed.
I suspect (but I am not certain) that the Pro Mini will work fine at any voltage up to 5v. The point about Atmega 328 chips is that they cannot work at 16MHz when powered at 3.3v so they must be operated at 8MHz. But an 8MHz Atmega chip will work fine at 5v.
The common ProMinis are 16MHz/5V and 8MHz/3.3V. You can't change this without desoldering and
replacing the crystal and/or regulator on the board. Feeding 5V to the output of a 3.3V regulator is likely
to cause problems, it depends on the particular regulator. The ATmega328 is the same, its capable of
operation from ~1.8V to 5.5V (assuming the brown-out detector voltage is set appropriately and
the clock speed isn't too high for the voltage) Lower voltage and lower clock speed both reduce
power consumption dramatically, the 3V3 8MHz version taking perhaps 1/5th of the power of
the 5V 16MHz one.
For generating 3.3V from a LiPo you need a very low dropout regulator (<0.4V). Standard "low"-dropout
regulators have too much dropout. This is why numbers are better than adjectives in electronics!
