Raspberry Pi Card Reader

Introduction

These are files for setting up a Raspberry Pi (RPi) 3 running Raspbian Stretch Lite to log timestamped data from a card reader that uses keyboard emulation (i.e., most magnetic card readers). An Adafruit Ultimate GPS module is recommended for automatic timekeeping. Data are stored in CSV files.

Operation is headless; the primary interface for I/O with the RPi (besides the card reader) is via a FAT-formatted USB stick (Windows-compatible USB sticks) or via its web server located at http://10.23.45.1 when connected to the RPi's hotspot.

NB: You will not have access to the Internet while connected to the RPi's hotspot.

Setup

Boot the pi. Install the gpsd and gpsd-clients packages (apt-get install gpsd gpsd-clients). Also install the ntp package and disable systemd-timesyncd:

systemctl stop systemd-timesyncd.service
systemctl disable systemd-timesyncd.service

apt-get install ntp

Also install dnsmasq and hostapd for wireless access

apt-get install dnsmasq hostapd

And install apache2 for showing files

apt-get install apache2

Shutdown the pi. On a linux machine, mount the pi's microSD card's partition where the root directory resides. Extract the files in this directory to the RPi's root directory (/). The root directory is usually on the second partition on the microSD card.

Usage

Setting Time

Using the GPS module

Plug in the GPS module with the RPi off. Turn on the RPi.

Manually, using a USB stick

Without an RTC or GPS module, time must be set on the RPi every time it is plugged in (so avoid unplugging it).

To set approximate time on the RPi¹, create a file called current_date.txt in the root directory² of the USB stick with the current time formatted as shown below:

2017-02-13 18:00

To get more accurate timestamps, insert a future time and insert the USB stick at that future time.

An example current_date.txt file is in the /home/pi folder.

Setting Timezone

In addition to setting time, you may also wish to set the timezone if you'd like automatic daylight saving time time changes.

Look up your appropriate timezone under the TZ column on this page.

Create a file on a USB stick called timezone.txt with the timezone formatted the same way it is shown on the Wikipedia page (i.e., as shown below):

America/Los_Angeles

Plug the USB stick in the RPi.

Changing hotspot name and password

For security purposes, you should change the password in the /etc/hostapd/hostapd.conf file after connecting for the first time. To do so, log in to the RPi via SSH (if using Windows, you will first need to install an SSH client, such as PuTTY). On macOS and GNU/Linux, run:

ssh [email protected]

Enter the password (the default password for Raspbian's pi account is raspberry). Your terminal window should display [pi@raspberrypi:~ $] if login was successful. Then, edit the hostapd.conf file by running nano:

sudo nano /etc/hostapd/hostapd.conf

Navigate up and down the file using your keyboard's arrow keys.

Find the ssid=Badger line and change the hotspot's name to a name of your choice (e.g., ssid=CardReader).

Find the wpa_passphrase=BadgerBadgerSnake line and change the hotspot's password to a password of your choice (e.g., wpa_passphrase=AmazingPassword).

Press Ctrl + O on your keyboard and then hit Return to save the file. Then press Ctrl + X to exit nano. Reboot the raspberry pi:

sudo shutdown -r now

Obtaining Data

Using a Web browser

With a Wi-Fi enabled computer, tablet, or phone, connect to the access point (default name is Badger). The default password is BadgerBadgerSnake. In your Web browser, navigate to http://10.23.45.1. Click or tap on any of the CSV file(s) named cards_read (e.g., cards_read_S2018.csv) and save the file using your Web browser's save functionality.

Using a USB stick

CSV files modified within the last 90 days (or earlier, if no data have been retrieved for longer than 90 days) are automatically copied to a USB stick upon insertion.

There is no audible or visual notification for when the process is complete, but waiting a few seconds after the USB stick stops flashing usually allows sufficient time for copying to finish. It should then be safe to remove the USB stick.

Files older than 90 days are compressed and stored in a backup folder on the RPi after they have been retrieved. The backup files cannot be retrieved using a USB stick, but can be viewed by removing the RPi's microSD card and viewing the contents on a different computer. These files should be removed in the unlikely event that the RPi runs out of disk space.

Footnotes

¹The RPi doesn't have a real-time clock
²More accurately, the root directory of the first filesystem on the USB stick. Most USB sticks only have one filesystem, however.