1. airsoft-o-tactical (1.0) (01.02.2020)

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Although I was working with linear voltage regulators before (using AMS1117) - for USB use, I wanted to make another device that would work with 18650 LIPO battery, and would use 3.3V. And this device should have as less fragile components as possible. See discussion on stackexchange on choosing specific chip.

This is also my first experiment device with lipo protection - initially I was using FS312F-G, but it requires also external mosfet, has 6 pins and is much easier to mess up. (And also is external device, so costs money to assemble). I was vary happy with XB3303A chip that is tiny, has only 3 pins and does not require much external components.

What worked (or was tested)

• ESP-12F works! Blink is ok.
• Programming through Serial pins.
• 3.3V converter does work, shifting voltage to 3.3V.
• Lipo Unvervoltage protection also works
• WS2812B socket and LED’s control
• Buttons
• ADC
• Flash pad

What does not work as expected:

• I’ve messed up PullUp/Pulldown for GPIO15 and GPIO00, so device failed to start for me. And I’ve ordered 30 pcbs to be assembled! So one reistor array should be desoldered and 3 resistors should be added.
• For some reason NPN transistor was placed incorrect - causing short circuit on the board. It took me 6 boards, desoldering components one-by-one to get it wright. So no buzzer this time.
• Flash pad has not the best location - I should point carefully with tweezers for it to work. Also it’s too big - i would need to find someting like 1.27mm.
• Buttons are too close to each other. I need some fancy case for them to work.
• LiPo undervoltage protection - not as expected - it kills voltage supply at around 2.5 volts. Hope that it would would not destroy 18650 batteries for me.
• LiPo battery reverse protection does not seem to work - it consumes around 1 amp of voltage and overheats.

2. airsoft-o-tactical (1.2) (01.09.2020)

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This is fixed / upgraded version of 1.0 revision. I had to re-design power lanes to allow for extra MicroSd slot on the back and usb on the front. Still compact, now more powerful!

Change list:

• Fixed resistors for ESP - now ESP can just be thrown there and would work
• Added MicroUSB for non-mobile applications
• Added reset 1.27x2 pin
• Replaced programmer pads with 1.27x2 pin on the left side. Works great.
• Added MicroSD slot on the bottom side.
• Moved power pads on the both sides. Now can use 2.54 90 degree pin.

What worked (or was tested)

• ADC - battery voltage is reporting correctly. It was hard to mess it up.

What does not work as expected:

• As much as I like LCSC - Original MicroSD slot is super-expensive on LCSC - after shipping + taxes. I found same one on AliExpress for $9.50 for 100.

3. Witty Cloud Spider (3.3) (13.05.2020)

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I was looking a way how to integrate ESP12-E/ESP-12F with my smart home thigies. One of the first devices I’ve bought was Witty cloud - It’s a great form factor and concept, so I was trying to make my own pluggable device like that.

The idea here was to use AMS1117-3.3V linear voltage converter to drop down voltage from 5v to 3.3v.

Changes in 3.3:

• Added ADC solder pad and resistors + capacitor for measuring input voltage.
• Some reordering of components to fit everything better

Changes in 3.2:

• Added microusb (2-pin, power only)
• Removed Flash pin - replaced with solder pag.
• Added ground plane on top layer
• Added 5V output
• Added through hole under AMS1117 for better heat dissipation
• Added better text
• Updated pins definition
• Better tracks to some pins

Changes in 2.0:

• Removed Flash Button - replaced it with x2 2.54 pins
• Added separate plane under AMS1117

Changes in 1.0:

• My first revision of the board, failed one. I’ve messed up mandatory pins and spent a lot of time trying to fix it. See that