2 layers

Endless endless eight

Q: What parts does the Endless endless eight use?

11 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Q: Where can I download the Endless endless eight KiCad files?

From the likeablob/endless-endless-eight repository on GitHub, at the commit this page was made from: the board is kicad/endless-endless-eight.kicad_pcb and its schematic kicad/endless-endless-eight.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Q: Can I use the Endless endless eight design in my own project?

Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

likeablob/endless-endless-eight5

Never ending summer again. (Solar-powered AVI player based on ESP32/ULP)

Full screen GitHub .kicad_pcb

Copper layers: 2
Thickness: 1.6 mm
Parts: 11
Nets: 34
Pads: 68
Tracks, vias: 0, 0
Routed: Not yet
KiCad: KiCad 6 (file 20211014)
Created: 14 Feb 2022
Updated: 6 Mar 2022

Overview

Endless endless eight is an open-source printed circuit board by likeablob, from the likeablob/endless-endless-eight repository on GitHub, published under the MIT licence. It is a 2-layer board with 11 parts on 34 nets.

Its parts include 6 resistors, 2 transistors, 2 connectors and 1 IC. It belongs with the ESP32 boards of this library.

README

README.md

The clip played is from The Melancholy of Haruhi Suzumiya (2009).

Endless Endless Eight

A self-sustained AVI player to replay the summer days.

ESP32 to play MJPEG-AVI video files from microSD at 24 fps.
Utilizes ULP coprocessor for BAT voltage monitoring, Deep Sleep management etc.
5V solar panel and small LiPo battery as the main power source.
(Planned) LTC3130-1 for more efficient power conversion.

BOM

WIP

ESP32 WeMos LOLIN32 Lite
ST7735 80x160 LCD module
microSD card (>= 2 GB)
5V 2W solar panel

Prepare video files

All the video files to be placed on the MicroSD must be MJPEG-encoded AVI.

# Transcode EP 12~19 to ee_%d.avi, with scaling and cropping
$ seq 12 19 | xargs -L 1 -P1 -I% bash -c 'ffmpeg -i ee_%.mp4 -r 24 -vf scale=160:-1,crop=160:80 -vcodec mjpeg -q:v 5 -an ee_%.avi -y'

See sdcard/ for a set of sample vid files. These are converted from BigBuckBunny.mp4.

# The sample vid files were from
$ seq 12 19 | xargs -L 1 -P1 -I% bash -c 'ffmpeg -ss $(((% - 12)*2)) -to $(((% - 12 + 1) * 2)) -i BigBuckBunny.mp4 -r 24 -vf scale=160:-1,crop=160:80 -vcodec mjpeg -q:v 5 -an ee_%.avi -y'

Build firmware

$ git clone https://github.com/likeablob/endless-endless-eight.git
$ cd endless-endless-eight

$ cp include/user_config.g.template cp include/user_config.h
$ code include/user_config.h

$ pio run || pio run # The very 1st run may fail due to ulptool-pio
$ pio run -t upload

Print enclosure

See ./enclosure.

How it works

State transitions

Centering on the deep sleep mode, this application has several wake-up states as depicted in the following diagram.

The application switches back-and-forth between the nominal mode and deep sleep depending on the battery voltage. (See Power management strategy for details.)
Also, under the certain condition, it wakes in;
- Emergency mode to prepare for a complete power loss (See State persistence)
- Periodic Reporting mode for reporting housekeeping data via MQTT
Basically every wake up transition is triggered by the ULP routine.

mermaid

stateDiagram-v2
    Playing: Playing Video (Nominal)
    [*] --> Playing
    Playing --> DeepSleep: At low battery
    DeepSleep --> Playing: At high battery

    DeepSleep --> Emergency: At very low battery
    Emergency --> DeepSleep: ASAP

    DeepSleep --> PeriodicReporting: Every 30 minutes
    PeriodicReporting --> DeepSleep: ASAP

Power management strategy

It's quite simple; Wake the Main CPU up if the battery voltage (BAT_V) >= 3.9 V and put into sleep if BAT_V <= 3.75 V.
The ULP co-processor executes own routine every one second, but still is able to keep the deep sleep current consumption at uA-level.

mermaid

flowchart TB
  subgraph CPU["Main CPU"]
    %% flow
    power_boot(" ")
    boot("Boot")
    check_ulp_boot{"Wake by ULP?"}
    init_ulp["Init ULP routine"]

    %% flow
    init_loop(" ")
    check_batv_sleep{"BAT_V <= SLEEP_TH"}
    sleep("Deep sleep")

    power_boot --> boot --> check_ulp_boot
    check_ulp_boot -->|"Yes"| init_loop
    check_ulp_boot -->|"No"| init_ulp --> init_loop

    init_loop --> check_batv_sleep
    check_batv_sleep -->|"Yes"| sleep
    check_batv_sleep -->|"No"| init_loop
    sleep -.-> |"Wake by ULP"| boot
  end

  subgraph ULP

State persistence

The play state such as a file playing, its position and loop count etc. are kept over deep sleep or even complete power outage, thanks to ~~Nagato~~ RTC SLOW MEM and Non-Volatile Storage. The former is volatile but survives deep sleep, and the latter is nothing but a reserved region in flash.

In short there are two pathways for each storage.

A. Save to RTC_SLOW_MEM before entering deep sleep. Restore from RTC_SLOW_MEM after waking up from deep sleep.
B. Save to NVS at very-low battery voltage. Restore from NVS on boot.

Note: About B., the ULP routine wakes the main CPU in the Emergency mode when BAT_V <= 3.55 V. This happens only once and the related flag will be cleared by the main CPU after normal wake up.

mermaid

flowchart
  %% nodes
  init(" ")
  check_ulp_boot{"Wake by ULP?"}
  restore_from_nvs["Restore from Non-volatile storage"]
  restore_from_rtc["Restore from RTC SLOW RAM\n(Volatile, Deep-sleep persistent)"]
  check_ulp_flag_emergency{"Emergency Mode?\n(caused by very low battery)"}
  save_to_nvs["Save to Non-volatile storage"]
  sleep("Deep sleep")
  init_loop("Main Loop")
  check_low_bat{"Low battery?"}
  save_to_rtc["Save to RTC SLOW MEM"]

  init ---> check_ulp_boot
  check_ulp_boot -->|"Yes"| check_ulp_flag_emergency
  check_ulp_boot -->|"No"| restore_from_nvs --> init_loop
  check_ulp_flag_emergency --> |"Yes"| save_to_nvs --> sleep
  check_ulp_flag_emergency --> |"No"| restore_from_rtc --> init_loop

  init_loop --> check_low_bat
  check_low_bat --> |"Yes"| save_to_rtc --> sleep
  check_low_bat --> |"No"| init_loop

  sleep -.-> init

LICENSE

MIT

Dependencies

This projects is here thanks to a lot of superb OSS libraries. See platformio.ini for details. Thank you to all the devs.

Category and platform

ESP32

Project files

Show this board on your page

https://pcbkit.io/boards/likeablob/endless-endless-eight

The board's own page, for a message or a post.

Source

Repository: likeablob/endless-endless-eight
Board file: kicad/endless-endless-eight.kicad_pcb
Commit: a8537b5
Licence: MIT

Parts

Qty	Value	Footprint	References
4	10k	Resistor_SMD:R_0603_1608Metric	R2, R3, R4, R5
1	0.96in_80x160_st7735s_LCD_module	Connector_PinSocket_2.54mm:PinSocket_1x08_P2.54mm_Vertical	J1
1	100	Resistor_SMD:R_0603_1608Metric	R1
1	2k	Resistor_SMD:R_0603_1608Metric	R6
1	Micro_SD_Card_Det	Connector_Card:microSD_HC_Hirose_DM3BT-DSF-PEJS	J2
1	Q_NMOS_GSD	Package_TO_SOT_SMD:SOT-23	Q1
1	Q_PMOS_GSD	Package_TO_SOT_SMD:SOT-23	Q2
1	esp32_wemos_lolin32_lite	wemos_lolin32_lite:esp32_wemos_lolin32_lite	U1

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Questions

What parts does the Endless endless eight use?

11 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Endless endless eight KiCad files?

From the likeablob/endless-endless-eight repository on GitHub, at the commit this page was made from: the board is kicad/endless-endless-eight.kicad_pcb and its schematic kicad/endless-endless-eight.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Endless endless eight design in my own project?

Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).