Internet of Batteries: DEF CON 27 - "They don't support that"

BoI | Definition: Noun, Battery of Internets

Welcome to the Internet of Batteries: DEF CON 27 Edition! We've been told that the SAO standard "doesn't support" a battery back-powering the circuit on the VCC, which means we've done the most logical thing...Built a badge/SAO hybrid to support back-powering through it's pinout! While the badge is compatible with SAO 1.69bis, if plugged in to a DC27 badge it will most likely blow up the moon.

This project created a simple (and mostly-safe) battery badge which back/forward-powers any electronic badge & add-on via VCC pins, supplying a 500mA @ 3.3V while keeping track of how much power is drawn via back-powering and forward powering other badges and SAOs. This badge runs off of it's own power, and is able to operate as a standalone unit. To view power usage statistics users connect to the Captive Arcade^TM on the ESP32 to view local battery power consumption and discharge stats.

Additionally, there is a WiFi Mesh Network (Itero) which powers the IoB. Through this network you can send broadcast messages to one big group chat, or sent PMs to up to 25 added devices. To scan for available nodes in the area, add other batteries to your "friends" list, and interact with group & private chat, you will need to connect to the Captive Arcade^TM. When connected, "Friends" and scanned nodes will show green.

Jump Start

Power switch ON to charge
If LEDs flash on boot, boi is in safe mode, charge it
BTN 1 on boot = force safe mode - faster charge
BTN 1 + BTN 2 on boot = factory reset
Orient VCC on headers
Drink all the booze
Hack all the things
See you @DEFCON 28!

Better Instructions

Power switch must be in the ON position to charge
If the battery voltage is TOO LOW, the LEDS will flash ONCE on reboot, then go dark and output current battery voltage on serial out (115200). Once above 3.7v the battery should show animation while charging if rebooted at that time

There are FIVE buttons on the DC27 version of the Internet of Batteries:

Button	Description	Actions
RESET	This button is located on the BACK of the DEF CELL, under the battery next to the power switch	This resets the Boi
BTN 1	Cycle mode, 2x toggles Captive Arcade^TM	CLK 1 : Capacity -> Node Count -> Party!!! DBL CLK 1 : Toggle Captive Arcade
BTN 2	Toggles backpower on SAO rail on/off	Auto-off if voltage is detected going the wrong way across the SHUNT resistor
DEFLOCK	Stealth touch button where it says "DEF CON XXVII" in the white strip at the top of the battery.	Press and hold to cycle through and set light show for each mode
BONUS	Press and hold for a fun throwback, does not currently actually show capacity	boop booP boOP bOOP BOOP! BOOP! BOOP! BOOP!

Boot Order

This is very important and will help to minimize blowing up like a Note in the sky

Detect power on rails: If voltage on LiPoly is too low, FLASH LEDS ONCE and boot in to "Safe Mode"
Button assignment : BTN_PWR, BTN_ACT
LED assignment : LED_LEV20, LED_LEV40, LED_LEV60, LED_LEV80, LED_LEV100, LED_S_NODE, LED_S_BATT, LED_POUT_ON
DNS setup
WiFi setup
Enable Captive Arcade^TM if no password is set
React to user input
If voltage across shunt changes direction, and BACKPOWER is ON, force power state to NO_BACKPOWER

Board Layout

Front:

<code><div>    
back:  
      _____
 ____|ESP32|____ ---
|USB |     |PWR | |   
|STFF|_____|STFF| |   
|    SAO SAO    | |    
|USB            | | 
|    Battery    |~6.5cm
|    Goes       | |   
|    Here       | |  
|         INA219| |
|SAO_SWITCH__SAO| |
|_______________|---
|-----~3.5cm----|

front: 
      _____
 ____|_____|____
|               |
| DEF CON XXIIV |
|    SAO SAO  D |
| BTN1 LED    E |
| L L  LED    F |
| E E  LED    C |
| D D  LED    E |
| BTN2 LED    L |
|     SHUNT   L |
|SAO_________SAO|
</div>

How to flash new firmware

Note: We had to modify the libraries for the Adafruit INA219 and ASyncTCP in order to pull this off. Copies are provided in the source repo and should auto-import on build with PlatformIO

Install VS Code
Install PlatformIO Extension
Clone this repository and open in VS Code
Plug Boi in to USB and identify the correct COM port if necessary (if only one COM device, should auto-select)
Test build code with PlatformIO (CTRL+SHIFT+B)
Upload code with PlatformIO (CTRL+SHIFT+U)

Note: There are preferences stored in flash which persist even when flashing updated code. To reset ALL data on the device you must perform a full flash reset from PlatformIO, then flash the desired version of the firmware to the now empty device

Donations

<code><div>Bitcoin Cash is pretty sweet:  
    1CbJsCqH9btitkRr13m11RribyF6m7EUTZ

Bitcoin is cool too: 
    1GrnYwUCAsQY3oejdu8CRutnG55Wi7bXHz  

1 DOGE == 1 DOGE: 
    DNsRM5gPEA5MrGByi1MyWfbLWyuksvK5fC    
</div>