$ fwup nerves_livebook_rpi4.fw
Use 15.84 GB memory card found at /dev/rdisk2? [y/N] y

$ sudo NERVES_WIFI_SSID='access_point' NERVES_WIFI_PASSPHRASE='passphrase' fwup nerves_livebook_rpi4.fw

defmodule Aht20.Reader do
 alias Circuits.I2C

 @i2c_bus "i2c-1"
 @i2c_addr 0x38
 @initialization_command <<0xBE, 0x08, 0x00>>
 @trigger_measurement_command <<0xAC, 0x33, 0x00>>
 @two_pow_20 :math.pow(2, 20)

 def read do
 {:ok, ref} = I2C.open(@i2c_bus)

 I2C.write(ref, @i2c_addr, @initialization_command)
 Process.sleep(10)

 I2C.write(ref, @i2c_addr, @trigger_measurement_command)
 Process.sleep(80)

 ret = I2C.read(ref, @i2c_addr, 7)

 I2C.close(ref)

 value(ret)
 end

 defp value({:ok, val}), do: {:ok, convert(val)}

 defp value(_), do: :error

 defp convert(<<_, raw_humi::20, raw_temp::20, _>>) do
 humi = Float.round(raw_humi * 100 / @two_pow_20, 1)
 temp = Float.round(raw_temp * 200 / @two_pow_20 - 50.0, 1)

 {temp, humi}
 end
end

Aht20.Reader.read()

alias VegaLite, as: Vl

layers = 
 for {layer, color} <- [temp: :red, humi: :blue] do
 Vl.new()
 |> Vl.mark(:line)
 |> Vl.encode_field(:x, "iteration", type: :quantitative)
 |> Vl.encode_field(:y, Atom.to_string(layer), type: :quantitative, title: "℃, %")
 |> Vl.encode(:color, value: color, datum: Atom.to_string(layer))
 end

widget = Vl.new(width: 500, height: 200)
 |> Vl.layers(layers)
 |> Kino.VegaLite.new()

Kino.VegaLite.periodically(widget, 200, 0, fn i ->
 {:ok, {temp, humi}} = Aht20.Reader.read()
 point = %{temp: temp, humi: humi, iteration: i}
 
 Kino.VegaLite.push(widget, point, window: 1000)
 {:cont, i + 1}
end)

Mix.install([
 {:vega_lite, "~> 0.1.0"},
 {:kino, "~> 0.2.0"}
])

alias VegaLite, as: Vl

memory = [
 total: :red,
 processes: :yellow,
 atom: :green,
 binary: :pink,
 code: :orange,
 ets: :blue
]

layers = 
 for {layer, color} <- memory do
 Vl.new()
 |> Vl.mark(:line)
 |> Vl.encode_field(:x, "iteration", type: :quantitative)
 |> Vl.encode_field(:y, Atom.to_string(layer), type: :quantitative, title: "Memory usage (MB)")
 |> Vl.encode(:color, value: color, datum: Atom.to_string(layer))
 end

widget = Vl.new(width: 500, height: 200)
 |> Vl.layers(layers)
 |> Kino.VegaLite.new()

Kino.VegaLite.periodically(widget, 200, 0, fn i ->
 point =
 :erlang.memory()
 |> Enum.map(fn {type, bytes} -> {type, bytes / 1_000_000} end)
 |> Map.new()
 |> Map.put(:iteration, i)
 
 Kino.VegaLite.push(widget, point, window: 1000)
 {:cont, i + 1}
end)

for i <- 1..1_000_000 do
 :"atom#{i}"
end

$ mkdir livebook_project
$ cd livebook_project
$ git clone https://github.com/fhunleth/nerves_livebook.git
$ git clone https://github.com/nerves-project/nerves_system_rpi4.git custom_rpi4 -b v1.16.1

-defmodule NervesSystemRpi4.MixProject do
+defmodule CustomRpi4.MixProject do
 use Mix.Project
 
- @github_organization "nerves-project"
- @app :nerves_system_rpi4
+ @github_organization "TORIFUKUKaiou"
+ @app :custom_rpi4

CONFIG_PPP=m
CONFIG_PPP_BSDCOMP=m
CONFIG_PPP_DEFLATE=m
CONFIG_PPP_FILTER=y
CONFIG_PPP_MPPE=m
CONFIG_PPP_MULTILINK=y
CONFIG_PPP_ASYNC=m
CONFIG_PPP_SYNC_TTY=m
CONFIG_USB_NET_CDC_NCM=m
CONFIG_USB_NET_HUAWEI_CDC_NCM=m
CONFIG_USB_NET_QMI_WWAN=m
CONFIG_USB_SERIAL_OPTION=m

BR2_PACKAGE_USB_MODESWITCH=y
BR2_PACKAGE_PPPD=y
BR2_PACKAGE_PPPD_FILTER=y
BR2_PACKAGE_BUSYBOX_CONFIG_FRAGMENT_FILES="${NERVES_DEFCONFIG_DIR}/busybox.fragment"

CONFIG_MKNOD=y
CONFIG_WC=y

diff --git a/mix.exs b/mix.exs
index 0ca7bbb..558b54d 100644
--- a/mix.exs
+++ b/mix.exs
@@ -13,7 +13,8 @@ defmodule NervesLivebook.MixProject do
 :bbb,
 :osd32mp1,
 :x86_64,
- :npi_imx6ull
+ :npi_imx6ull,
+ :custom_rpi4
 ]
 
 def project do
@@ -76,7 +77,8 @@ defmodule NervesLivebook.MixProject do
 {:nerves_system_bbb, "~> 2.10", runtime: false, targets: :bbb},
 {:nerves_system_osd32mp1, "~> 0.6", runtime: false, targets: :osd32mp1},
 {:nerves_system_x86_64, "~> 1.15", runtime: false, targets: :x86_64},
- {:nerves_system_npi_imx6ull, "~> 0.2", runtime: false, targets: :npi_imx6ull}
+ {:nerves_system_npi_imx6ull, "~> 0.2", runtime: false, targets: :npi_imx6ull},
+ {:custom_rpi4, path: "../custom_rpi4", runtime: false, targets: :custom_rpi4, nerves: [compile: true]},
+ {:elixircom, "~> 0.2.0", targets: @all_targets}
 ]
 end

# This chatfile was generated by pppconfig 2.3.18.
# Please do not delete any of the comments. Pppconfig needs them.
# 
# ispauth CHAP
# abortstring
ABORT BUSY ABORT 'NO CARRIER' ABORT VOICE ABORT 'NO DIALTONE' ABORT 'NO DIAL TONE' ABORT 'NO ANSWER' ABORT DELAYED
# modeminit
'' ATZ
'' ATH
# ispnumber
OK-AT-OK "ATDT*99***1#"
# ispconnect
CONNECT \d\c
# prelogin

# ispname
# isppassword
# postlogin

# end of pppconfig stuff

# Secrets for authentication using CHAP
# client server secret IP addresses


sora * sora
"sora@soracom.io" * "sora"
"sora@soracom.io" * "sora"

# This optionfile was generated by pppconfig 2.3.18. 
# 
#
hide-password 
noauth
connect "/usr/sbin/chat -v -f /etc/chatscripts/soracom"
debug
/dev/ttyUSB2
115200
defaultroute
noipdefault 
user "sora@soracom.io"

ipparam soracom

import Config

# Configure the network using vintage_net
# See https://github.com/nerves-networking/vintage_net for more information
config :vintage_net,
 regulatory_domain: "US",
 config: [
 {"usb0", %{type: VintageNetDirect}},
 {"eth0", %{type: VintageNetEthernet, ipv4: %{method: :dhcp}}},
 {"wlan0", %{type: VintageNetWiFi}}
 ]

$ cd livebook_project/nerves_livebook
$ export MIX_TARGET=custom_rpi4
$ mix deps.get
$ mix firmware

$ cd _build/custom_rpi4_dev/nerves/images/
$ sudo NERVES_WIFI_SSID='access_point' NERVES_WIFI_PASSPHRASE='passphrase' fwup nerves_livebook.fw

$ ssh livebook@nerves.local

iex> lsusb()
Bus 001 Device 004: ID 1004:618f NTT DOCOMO, INC. docomo L02C
...

iex> Elixircom.run("/dev/ttyUSB2")

AT+COPS=1,2,"44010"
OK # 端末から返される
~.

defmodule CellularSample do
 use Toolshed

 def connect do
 cmd("mknod /dev/ppp c 108 0")
 cmd("pon soracom")
 end

 def update_route do
 cmd("ip rou delete default")
 cmd("ip rou add default via #{ip_address()} dev ppp0")
 end

 # ifconfigしてIP Addressを取得している感じです
 defp ip_address do
 {:ok, list} = :inet.getifaddrs()

 Enum.filter(list, fn {type, _} -> type == 'ppp0' end)
 |> Enum.at(0)
 |> elem(1)
 |> Enum.at(1)
 |> elem(1)
 |> Tuple.to_list()
 |> Enum.join(".")
 end
end

CellularSample.connect()
CellularSample.update_route()

iex> ping "pong.soracom.io" 
Press enter to stop
Response from pong.soracom.io (100.127.100.127): time=69.427ms
Response from pong.soracom.io (100.127.100.127): time=66.683ms
Response from pong.soracom.io (100.127.100.127): time=77.495ms