#ESP32 FaerFly - Development Board Imogen Wren Business Card PCB

Project Outline

The project is a business card that can be handed out at gigs and work, and also a fun project to build!

Requirements

1. A PCB business card I can hand out to people at gigs / work to advertise myself
2. A fun electronics project or thing

Idea

1. Mini pocket lightshow. Rechargable and interactive. Probably get it fabbed so it isnt a soldering project, but include a programming port so it can be reprogrammed easily.
   Advantages:
   • Fun programming challenge - Can link to repo with working code in case of bricking
   • Card more likely to be used in the open and interacted with over time
   • Would have to be handed out with everything attached
   • Could exclude battery and make a point of indicating to reuse broken disposible vape for battery. Recycling electronic waste!

Strech Features

• NFC Tap phone to link to linktree?
• Edge connectors could be used as both touch interface, and connection to other hardware. Generic port? Is this now a new form we are trying to invent for development boards?
• 3d printed case for different functions, like exposed touch pins,

Circuit Snippets

WS2821b LED Implementation

https://cdn-shop.adafruit.com/datasheets/WS2812B.pdf

• Vdd = 3.5 - 5.6
• Vinput = VDD +-0.5

Battery can be unregulated direct to LEDs & regulated to microcontroller Slot for 2nd regulator for powering with 2s? or KISS

I think KISS

Charging IC and LOw Voltage Cutoff

https://www.mouser.co.uk/ProductDetail/Littelfuse/SMAJ350A?

Research

AtTiny85 Interface

DrAzzy - ATtiny Obsessee Jan '20post #2 If you use my core (board manager url in sig), there is a serial bootloader (use the (optiboot) board def). But you will still need an ISP programmer or arduino running Arduino as ISP sketch to bootload it (usbasps and nano clones are both 3 bucks or so on ebay/aliexpress, either is suitable). You will also need a 0.1uf cap and 10k resistor for the autoreset circuit so the serial adapter can reset it into the bootloader. (Also, dont forget that you also need a 0.1uf ceramic cap between power and ground close to the t85 ti ensure reliable operation; without this the chip may behave erratically depending on circumstances - I mention this because it is very often omitted in designs I see here, particularly with tinies. You always need this for digital ICs unless otherwise specified in the datasheet. With the t85, if on breadboard or protoboard, i usually put this across the top of the chip to minimize the distance between cap and chip)

USB - SPI Bridge

https://www.mouser.co.uk/ProductDetail/Microchip-Technology/MIC2550AYTS

USB C Connectors

https://www.mouser.co.uk/ProductDetail/Amphenol-Commercial-Products/124018402112A https://www.lcsc.com/product-detail/span-style-background-color-ff0-USB-span-Connectors_G-Switch-GT-USB-7007A_C5299422.html

LiPo Battery Charging

1S

https://uk.rs-online.com/web/p/battery-management/7386360 https://www.mouser.co.uk/ProductDetail/Microchip-Technology-Atmel/MCP73832T-5ACI-OT https://www.mouser.co.uk/datasheet/2/268/20001984g-846362.pdf

2S

https://www.mouser.co.uk/ProductDetail/Microchip-Technology/MCP73844T-820I-MS

This option needs regulator to 5v

Microcontroller Options

AtTiny85

• https://uk.farnell.com/microchip/attiny85-20su/mcu-8bit-attiny-20mhz-wsoic-8/dp/1455164
• Feels more "Haxxor" using a tiny processor
• More Difficult to implement
• The device achieves a throughput of 20 MIPS at 20 MHz and operates between 2.7 to 5.5V.
  • In voltage range
• Have code almost ready to run https://github.com/Imogen-Wren-Studios/unicorn-attiny85

SAMD21

• 3.3v MUST BE REGULATED
• Lots of experience with device
• https://www.mouser.co.uk/ProductDetail/Microchip-Technology/ATSAMD21E16L-AF?qs=9KdFJXLqUo%252B5fCZYsYcg9g%3D%3D

AtMega382p

• Most commonly understood platform - better engagement
• https://www.lcsc.com/product-detail/Microcontroller-Units-MCUs-MPUs-SOCs_Microchip-Tech-ATMEGA328P-AU_C14877.html
• Expensive
• in stock ATM
• 1.8 - 5.5v - No Need for Regulator
  • Qty. Unit Price Ext. Price
  • 1+ US $3.045
  • 10+ US $2.7126 - US$ 27.13

ESP32

• 3v3 Only - needs regulating
• Wifiability gives further haxxor abilities
• OTA Updates https://www.lcsc.com/product-detail/WiFi-Modules_Espressif-Systems-ESP32-WROOM-32-N4_C82899.html
• Have some code that could be used: https://github.com/Imogen-Wren-Studios/esp32-ws2812b-glediator
• Price:
  • 1+ - US$3.2455
  • 10+ - US$2.9273

Capaciative Sensing

https://www.instructables.com/Capacitive-Sensing-for-Dummies/ Seems to mostly be used with a microcontroller, havnt managed to find an analog audio implementation yet

https://docs.arduino.cc/built-in-examples/analog/Smoothing Smoothing Data from Capacative touch sensor

Continued Development

Now the project has become more clearly defined, it is an ESP development board with built in WS2821b LEDs designed to be used as a wearable badge, or a light up stand for 3D printing projects. It contains mounting tabs to assit in adding diffusers and optics. The wifi can be used to coordinate groups of them to sync colours around the room.

Version 2 Development

After using version 1 for a little time, some clear places to improve have materialised.

1. [] Replace GPIO surface pins with through holes
2. [] Replace USB to serial with CP2102, CH340 is too flakey see CP2102 USB to UART
3. [] Add BMP280 temp sensor
4. [] Add Accellerometer
5. [] Add digital microphone? - test theory before committing
6. [] DMX interface? -> The DMX output required the use of a MAX485 transceiver connected to the TX-pin of the ESP in order to produce DMX output. If you need to use another pin for output than the TX-pin, you'll need to change this in the ESP-Dmx library itself. This setting is located in src/dependencies/dmx/ESPDMX.cpp on line 31.
7. Battery Positive to ADC1 (GPIO32-39) with 100k resistor for battery usermod
8. Change Battery Switch to switch between USB and battery (why didnt do this on version 1?!?!)
9. Check max charge current for BMS. Need at least 1A if possible 550mA max using 2k ohm shunt resistor

Does DMX make this project something it is not?