HiLetgo 3pcs Pro Mini ATmega328P 3.3V 8M Module Board with Crystal Oscillator Compatible Arduino Pro Mini Replace ATmega128

Always get what pay for. Good products, good price, good availability.

I have purchased other HiLetgo products and they have always worked well for me. So, unfortunately I did not read the reviews. In this case I was looking to buy a Arduino Pro Mini compatible board. The HiLetgo part advertised that it came with the bootloader installed, so, I should have been able to program it just like the other Pro Minis I have been using for my development. No such luck. I tried both the Arduino IDE and Sloeber Eclipse. Having spent over an hour trying to get these to work, I'm sending them back. While I see that others have been able to get them to eventually work, these devices do not function as advertised. Although they seem a great value, if I can buy a plug & play device, then the time saved is more valuable.

Liked - works reliably, takes a lot of abuse and still keeps on tickingDislikes - Not an issue with this specific supplier, but across multiple suppliers the header for the serial link is not consistent. Some suppliers the ground pins are on the right and other suppliers the ground pins are on the left side.

I am amending a 1 star review. If you follow some tutorials using Pro Mini boards online, using an FTDI USB breakout board, you're going to either run into sync errors, or access denied errors, in ardunio IDE. Make certain that your connection from the FTDI to this Pro Mini on the DTR pins is included. A lot of tutorials seem to not do this. I guess the official boards didn't require it.

Works great if you actually know what you're doing. These are rated at 3.3V so if you want magic smoke genies then just apply 5 volts.

First, I found the quality of the modules assembly to be good. However, I was not able to use the Arduino IDE to load a program using a USB to Serial converter as one would expect. I eventually discovered that the 3 modules I received did NOT have a bootloader installed as was specified in the HiLetgo ad. I contacted the seller for support providing a screen shot of the error message I received when trying to upload a program and they responded quickly, providing a pinout diagram and suggested IDE menu selections but no help regarding the error message. I did some investigation an learned that the error was typical of a module that DID NOT have a bootloader. To prove the point I built an ICSP and uploaded a proper bootloader. The module then performed as expected, hence, the CAUTION, be prepared to build or buy an ICSP device to burn the bootloader. I now notice several other reviewers commenting on the same problem of a missing bootloader. Unfortunately, these modules will be returned for a refund and I will look elsewhere as I am preparing to publish an article that will use the Arduino Pro Mini and I cannot reference this module from HiLetgo knowing that it will most likely cause problems. Other than the missing bootloader, the one module I got working seems to be OK.

Functions as expected

Out of 3 of these 3.3v pro minis none of them would take programming I thought at first it was me or a software issue so I plugged in 4 other ones ive had for a long time and each one programmed like a champ.Its not worth the gas to take them back to UPS to return. Amazon needs to change this policy and bring back the free pickup on junk they allow to be sold on their site . DO NOT BUY THESE total Garbage