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Building a Development Hotspot

This guide walks through the steps required to build a Development Hotspot that can send and receive packets over the wireless network, but not perform any blockchain mining functions.

System Requirements

To build a low-cost Development Hotspot, we recommend using a Raspberry Pi 3B+ or 4B running the latest Raspian Buster image with a RAK2245 Pi Hat installed, and a recommended 64GB sdcard. In theory any Linux host and any Semtech SX1301-based concentrator board that interfaces to the host via SPI can be used, but are untested as of this writing.

This README will assume a Raspberry Pi 3B+/4 with 1GB RAM + RAK2245 combination described above. This combination is available as a packaged product directly from RAK called the Pilot Gateway.

There are two distinct applications required in order for the Hotspot to send and receive LongFi packets, and route them to the correct internet hosted destination. Miner connects to the blockchain and forwards received packets to the correct address by inspecting an Organizationally Unique Identifier in the blockchain ledger, and concentrate interfaces with the LoRa concentrator via SPI and the miner via UDP to send and receive LongFi packets.

Raspberry Pi specific setup

The default Raspian image has a small swapfile of 100MB, which on a Pi with 1GB or less of RAM is insufficient for building some of the dependencies, such as RocksDB. To increase the swap size, first stop the swap:

sudo dphys-swapfile swapoff

Edit the swapfile configuration as root sudo nano /etc/dphys-swapfile and change the CONF_SWAPSIZE:


Save the file, then reboot:

sudo reboot

Next, enable SPI and I2C by running sudo raspi-config and selecting Interfacing Options, and enabling I2C and SPI from within the menu system.

Installing miner from Source

First, you'll need git. If you don't have it installed:

sudo apt-get install git

Clone the git repository:

git clone https://github.com/helium/miner.git

You will need to install the dependencies listed below in order to use the Miner.

Install Erlang

Miner has been tested against Erlang OTP 21.3.

To install OTP 21.3 in Raspian, we'll first acquire the Erlang package from Erlang Solutions and then install the dependencies:

wget https://packages.erlang-solutions.com/erlang/debian/pool/esl-erlang_21.3.3-1~raspbian~stretch_armhf.deb
sudo dpkg -i esl-erlang_21.3.3-1~raspbian~stretch_armhf.deb
sudo apt-get install -f

Install various other dependencies:

sudo apt-get install libdbus-1-dev autoconf automake libtool flex libgmp-dev cmake libsodium-dev libssl-dev bison libsnappy-dev libclang-dev doxygen

Compile the Miner

Once the Miner has been cloned and Erlang installed, we can create a release using rebar3. Rebar will handle all the Erlang dependencies and build the application. This will take a while:

cd miner
./rebar3 as prod release

Once this completes, you're ready to run the Miner.

Using the Miner

Congrats! You've installed the Miner 🚀 Now it's time to make some things happen.

Editing the configuration

The sys.config will need to be edited to match your configuration. Assuming you aren't using Helium Hotspot hardware you'll need to change the following lines of the configuration file:

vim _build/prod/rel/miner/releases/0.1.0/sys.config

Change the following settings:

{key, undefined} {use_ebus, false}

You should also edit log_root, base_dir and update_dir to be appropriate for whatever you prefer on your system.

Starting Up

You can run the Miner in the background, or via an interactive console.

To run in the background:

_build/prod/rel/miner/bin/miner start

To run via the interactive console:

_build/prod/rel/miner/bin/miner console

If you run in console mode, you'll need to open another terminal to execute any other commands.

Checking the peer-to-peer network

The Helium blockchain uses an Erlang implementation of libp2p. Because we expect Hotspot hardware to be installed in a wide variety of networking environments erlang-libp2p includes a number of additions to the core specification that provides support for NAT detection, proxying and relaying.

The first order of business once the Miner is running is to see if you're connected to any peers, whether your NAT type has been correctly identified, and that you have some listen addresses:

_build/prod/rel/miner/bin/miner peer book -s

You will see an output roughly like the following:

| address | name |listen_addrs|connections| nat |last_updated|
|/p2p/11dwT67atkEe1Ru6xhDqPhSXKXmNhWf3ZHxX5S4SXhcdmhw3Y1t|{ok,"genuine-steel-crocodile"}| 2 | 13 |symmetric| 3.148s |
| listen_addrs (prioritized) |
| /ip4/ |
| local | remote | p2p | name |
|/ip4/|/ip4/|/p2p/112GZJvJ4yUc7wubREyBHZ4BVYkWxQdY849LC2GGmwAnv73i5Ufy|{ok,"atomic-parchment-snail"} |
|/ip4/| /ip4/ |/p2p/112MtP4Um2UXo8FtDHeme1U5A91M6Jj3TZ3i2XTJ9vNUMawqoPVW| {ok,"fancy-glossy-rat"} |
|/ip4/| /ip4/ |/p2p/11AUHAqBatgrs2v6j3j75UQ73NyEYZoH41CdJ56P1SzeqqYjZ4o | {ok,"skinny-fuchsia-mink"} |
|/ip4/| /ip4/ |/p2p/11LBadhdCmwHFnTzCTucn6aSPieDajw4ri3kpgAoikgnEA62Dc6 | {ok,"skinny-lilac-mustang"} |
|/ip4/| /ip4/ |/p2p/11VjFZM14JK3oecVuVfYSgAM9oZy1J98kQW8AZMQgLZC4p4noih | {ok,"fast-pebble-snake"} |
|/ip4/| /ip4/ |/p2p/11apmNb8phR7WXMx8Pm65ycjVY16rjWw3PvhSeMFkviWAUu9KRD |{ok,"radiant-cobalt-tadpole"} |
|/ip4/| /ip4/ |/p2p/11ckxdQsReXpqwCrbbREZj6urEuNEGf2Zk5d4UnsuPMsJDSihwy |{ok,"orbiting-cream-starfish"}|
|/ip4/|/ip4/ |/p2p/11dj5k2dwSUE7fqFnwAHK9stLd3St9MJiJuaRnvvRgJjbRMZgKJ | {ok,"micro-tiger-tuna"} |
|/ip4/| /ip4/ |/p2p/11sRJ9L6nenuBDK8RNvswXThvu6aYyPNA7Rsq6bV1dWG1veyYaS | {ok,"curved-rouge-hedgehog"} |
|/ip4/|/ip4/ |/p2p/11tZZW54iY4WF481DmrMdVe2QVi2K9m6dXEZps6GvPTqyWZp5V3 |{ok,"harsh-honeysuckle-shark"}|
|/ip4/|/ip4/ |/p2p/11vsUeTb8g4KcELPctghGLSDWhUDGAEAkiAhERU3euC69HSNvca | {ok,"long-rosewood-boar"} |
|/ip4/|/ip4/ |/p2p/11wDt78AktL5ZMmV8ePxZWAu8wyVRLbArFeqhCVExzyd3HP6hQa | {ok,"fluffy-sand-yeti"} |
|/ip4/|/ip4/ |/p2p/11xxCzYzQAxhfazMVa6vi7QBD4ct85baw7FLG9KPmERVttXBKhQ |{ok,"beautiful-coffee-oyster"}|

As long as you have an address listed in listen_addrs and some peers in the table at the bottom, you're connected to the p2p network and good to go.

Loading the Genesis block

First, you need a genesis block from either the main network, or the Pescadero testnet. Get them here: mainnet or pescadero.

Once you've downloaded it, you'll need to use the CLI to load the genesis block in to your local miner:

_build/prod/rel/miner/bin/miner genesis load <path_to_genesis>

After the genesis block has been loaded, you should be able to check your block height and see at least the genesis block:

_build/prod/rel/miner/bin/miner info height

The first number is the election epoch, and the second number is the block height of your miner.

Installing concentrate from Source

Once you have miner running, you'll need concentrate to receive packets via SPI and the RAK2245 board and deliver them to the miner via UDP.

Clone the git repository:

git clone https://github.com/helium/concentrate.git

You will need to install the dependencies listed below in order to use the Miner.

Install Rust

First, rustup must be installed, which can be done as follows:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Compile Concentrate

Once you have concentrate and rustup installed, we can use Rust's package manager, Cargo, to build the concentrate application:

cd concentrate
git submodule update --init
cargo build

Once complete, you're ready to run concentrate.

Using concentrate

Start up concentrate and the longfi protocol wrapper by running:

./target/debug/concentrate serve &
./target/debug/concentrate longfi &

If you want to be able to see pretty printed packets in the console you can instead use:

./target/debug/concentrate serve -p
./target/debug/concentrate longfi &

You'll see output that looks something like this any time a packet is received:

received RxPacketLoRa { freq: 920600000, if_chain: 2, crc_check: Fail, timestamp: 2778.214131s, radio: R1, bandwidth: BW125kHz, spreading: SF7, coderate: 4/8, rssi: -117.0, snr: -11.5, snr_min: -15.0, snr_max: -8.0, crc: 4, payload: [225, 77, 252, 10, 79, 252, 5, 184, 159] }


That's it! Once you have miner and concentrate running you've built a Development Hotspot that can send and receive LongFi packets, and interact with the blockchain to deliver packets to their correct destination.