Field Day Registration Kiosk

I wrote this simple program to help my Amateur Radio club (North Fulton Amateur Radio League, https://nfarl.org) to register visitors on our annual Field Day event.

Over the years it became my sandbox to try and practice various ideas and development approaches. See the Development history below.

Deployment

The application is usually deployed on a Raspberry Pi or compatible boards. It can deployed on any other computer that you can leave in the park overnight.

Prerequisites

• Linux OS (any recent version will do)

• Go 1.22 and higher

• Git CLI

• sudo access on the target host

Build

1. Clone this repo on the target computer and cd into that directory.

2. Run make build. That will create a binary in the root directory.

3. Test it by running ./fieldday test.db. Enter one or two visitors. Check if they were added to the database by adding /list to the main URL (instead of /new).

Install

1. Run sudo make install. That will copy the binary and template files to /var/local/fieldday.

2. Run sudo make user. That will create a user named nfarl with a password fieldday and configure their environment (e.g. autostart of the browser in full screen mode, etc.). Note: the script works with the Raspbian OS and LXDE desktop. In the 2024 deployment I decided to use Orange Pi Zero 3 with Debian 12 (Bookworm) and XFCE4. Setting the browser properly required some manual steps that I haven’t automated yet.

Upgrade

1. git pull

2. make build

3. sudo make install

Real-time clock

The program adds timestamps to each visitor record automatically. But in the field the host doesn’t have any network connection so in case somebody turns it off the timestamps will be all wrong after that. To avoid such a situation you can add a simple battery-powered real-time clock (RTC) to Raspberry Pi and configure it accordingly.

This is the one I added to my installation: https://www.amazon.com/Makerfire%C2%AE-Raspberry-Module-DS1307-Battery/dp/B00ZOXWHK4/

This is a good instruction on how to configure it: https://pimylifeup.com/raspberry-pi-rtc/.

For Debian installation a found a good advice here: https://forum.armbian.com/topic/8838-external-rtc-ds1307-usage/

did you insert

rtc-ds1307
in /etc/modules?

and

echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-3/new_device  # I changed it to i2c-3 for my Orange Pi device
hwclock -s

in /etc/rc.local?

2024-06-19: after switching to Orange Pi Zero 3 with Debian 12 I had to make other changes to the RTC setup. When you add a new RTC device such as DS1307 and load its module it creates a new device called /dev/rtc1. I spent some time trying to figure out why my hwclock is lagging my system date (several seconds per minute). After changing several different RTC boards and their batteries I figured out the problem is not with the RTC board.

To make hwclock read from the new device you should first write to that device with hwclock -w --rtc /dev/rtc1 and then read from it with hwclock -r --rtc /dev/rtc1.

To configure the system time synchronization you have to edit this file: /usr/lib/udev/rules.d/85-hwclock.rules and change KERNEL==rtc0 to KERNEL=rtc1. Then /usr/lib/udev/hwclock-set will use this device to sync the system time.

Post-event processing

For the versions before 2024 I used SQLite. For SQLite use the following instructions to convert the visitors data to CSV: https://www.sqlitetutorial.net/sqlite-export-csv/

In 2024 I switched to BoltDB and Storm so it will require a separate tool. I’ll add it later.

Development history

Originally I started this project to learn Django (a Python framework for web development). The Django versions can be found here: https://github.com/pavelanni/field_day and https://github.com/pavelanni/field_day3

Field Day 2021

I used Jon Calhoun’s course (https://www.usegolang.com/) and created the first version of the application. This version used the Model-View-Controller approach, Gorilla web framework, and SQLite as a database with GORM.

Field Day 2022

I decided to simplify the application and switched from Gorilla to net/http from the standard library. My application is extremely simple so it’s not worth it using a full-fledged web framework for it. I simplified the application structure too, switched from MVC to much simpler architecture. I’m still using gorilla/schema to parse the form.

I started using GitHub actions to test and build the binary.

Field Day 2023

After FD 2022 I discovered that creation timestamps in the database were a bit off and figured out that the computer was turned off for the night and it couldn’t get it from anywhere because there was no network in the field. I decided to add a real-time clock (with a battery) to the installation.

I added a systemd service that would start the registration server and added those steps to the Makefile.

Field Day 2024

I decided to switch from SQLite to BoltDB. I started using BoltDB and Storm in a couple projects at work and it seemed reasonable to use it here. The main advantage is that because it doesn’t need CGO (like go-sqlite3 does) you 1) can compile the project much faster; 2) can cross-compile it for ARM on your laptop, and 3) don’t need GCC anymore.

I created a visitorstore package and put all the store operations into it. If necessary, it’s easy now to create a VisitorStore interface and implementations for various databases.