Ardubaby 2020

I have upgraded my previous tiny homemade Adruboy clone I called Ardubaby to Ardubaby 2020.
I replaced the 0.9" OLED with the 1.3" one.
Then simplified the circuit a bit by removing the extra battery charger board.
I replaced the 5V LDO regulator with a 4.2V one.
The LIPO battery can still get charged by connecting to the 5V of the USB port (i.e. RAW on the Pro micro board.). The battery protection circuit builtin to the battery will protect it against overcharging.

Here is the demo video.


I like the idea of using an IC socket as display / ISP connector :+1:

Not sure why you chose to replace the 5V regulator with a 4.2V

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As I am connecting the serial flash to the Pro Micro without a voltage level shifter, I want to reduce the voltage level on the Pro Micro a bit to avoid damage. I tried to replace the on board regulator with both either the 3.6V or the 4.2V regulator. Both seems to work. Power will be supplied by the 3.7V-4.2V LIPO battery anyway most of the time, but just in case when we connect to the USB port for programming and game loading. That may cause some damage over a long period. I also tested burning the firmware using a 5V USBasp to the Pro micro with the serial flash soldered on. I can burn your latest Cat3K homemade package firmware without any issue, even with the 5V USBasp (without modifying it to lower to 3V).
I choose 4.2V instead of 3.6V, as 4.2V allows me to work with a larger variety of I2C modules through the expansion port.

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I would test this to make sure, not all battery protection circuits will cut off on overvoltage despite manufacturer claims (and the result of it failing to do so is not pretty so best to be safe before trusting a circuit that you haven’t designed and built yourself).

Thanks for your comments. Yes, I have tested charging the battery overnight a few times. No overheat and the battery get charged. I will add this as a warning in my Circuit diagram descriptions. Thanks again.

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Awesome, better safe than sorry!

Is there some conversion problem for the images you use for the game loader? They seem… fuzzy…

I just captured the game main screens from the games web site. Or use power point to type in the letters for the game title. Then capture the screen. Then convert the jpg file to 128x64 png file using the preview tool from the Mac os. That may not be the best method.

It is probably the jpg compression on a screenshot? Do macs really make jpg for screenshots and not png? Yuck.

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JPG or PNG it is configurable.