I've noticed that there are two Pro Mini boards - 8Mhz, and 16Mhz. If using one of these to wirelessly talk to a Mega, which one is better? Also, the 8Mhz one is 3.3v. How do you connect a 5v module in a space saving manner (a million logic level convertors is the opposite of space saving)?
Depends if speed is an issue, for your application it might not be.
What 5V module are you connecting to what Microcontroller ?
I need to connect UV sensor (is compatible with 3.3 and 5), a rain detector (also 3.3 or 5v), and a 1602 LCD (only 5v) I am also a using an anemometer which outputs 0-5v. Will 5v on a analogue pin fry the board if the board is 3.3v?
How do I know if it is an issue? I'm transmitting data with a HC-12.
If all the stuff apart from the Pro Mini is 5v then its easier to use a 5V Pro Mini.
Speed could have been an issue depending on the project, which if you check your first post, you did not describe.
If your just reading a few sensors speed is unlikly to be an issue.
Yes, I am reading some sensors and transmitting the data to another board. I doubt that speed is a issue. The project is a weather station.
I didn't think it was important. I guess it was!
Thanks for your help @srnet!!
433.4-473.0 MHz is dangerous.
1 Like
I asked... They said it was fine!!!! 
It really doesn't bother me - I'd use an NRF24 if it was me, but I don't make all the decisions...
The 8Mhz Pro Mini is 3.3v only because its regulator is 3.3 volts. The board can run at 5V
If you put 5V into the Vcc the board will work fine. Don't connect anything to Vraw else you could blow the 3.3v regulator
I have a Pro Mini 8Mhz clone with a 3.3v regulator marked "S2PJ". I've been running 5V for some time while developing. I will likely remove the regulator before I build the final system.
1 Like
It is fine, working on a 434Mhz LoRa module on the bench right now, dont see that I am in any danger.
Do check the regulations for your particular country though, 434Mhz\HC12 might not be legal for you to use.
It is. I did all my dutiful research. I'm in Australia.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.