@mattb.tech/eretti

eRetti

TODO

• Try setting up nodogsplash
• Photo of setup
• Make video of usage
• Usage guide
• Setup script that installs software etc.

Items Required

• Raspberry Pi 3 B+
• USB Power pack and cable
• MicroSD card and adapter to plug into laptop
• Ethernet cable (to get started only)
• Laptop (all instructions here for Mac OS X laptop)

Setup

Tiny Core Install

First we need to install the base Tiny Core Linux system onto the MicroSD card. When I plug the SD card into my laptop it comes in as /dev/disk3, but please be aware that it may come up as something else on your system. If you blindly follow the commands below you will wipe /dev/disk3 on your system.

For the commands below to work you need to click to "eject" the MicroSD card you've plugged in to your laptop, otherwise it will complain: dd: /dev/disk3: Resource busy.

$ cd `mktemp -d`
$ wget http://www.tinycorelinux.net/11.x/armv7/test_releases/RPi/piCore-11.0beta1a.zip
$ unzip piCore-11.0beta1a.zip
$ sudo dd bs=4m if=piCore-11.0beta1a.img of=/dev/disk3

First Boot

Put the SD card in the Raspberry Pi, and boot it for the first time by connecting it to a USB power pack (or other USB power source). Connect up an Ethernet cable to get on the Internet as well.

You should be able to SSH into the machine after a few seconds. The password will be piCore.

$ ssh tc@box

First things first run...

tc@box:~$ filetool.sh -b

This will backup the current content of the system onto the SD card, which means the newly generated SSH keys will be the same next time you connect, avoiding grizzly security warnings.

Setting up partitions

Then we want to enter the interactive mode of fdisk to fiddle around with the partitions. We are aiming to (1) expand the size of the second partition which will store the software and (2) create another partition just to store our writing.

tc@box:~$ sudo fdisk -u /dev/mmcblk0

Start by entering p. This will output something like this...

Device       Boot StartCHS    EndCHS        StartLBA     EndLBA    Sectors  Size Id Type
/dev/mmcblk0p1    43,4,3      1023,37,5         8192     195692     187501 91.5M  6 FAT16
/dev/mmcblk0p2    1023,37,5   1023,37,5       195693     351943     156251 76.2M 83 Linux

Note down the StartLBA of /dev/mmcblk0p2 as we're going to need it later.

Next we want to delete the second partition. Enter d and then 2. Then we want to create a new primary partition in its place. Enter n, p and then 2. Then for the "First sector" enter the StartLBA number we noted down earlier. Enter +1024M giving us a generous 1Gb of storage space for our application.

We use a "linux" format for this second partition by entering t then 2 then 83.

Again, we'll want to enter p to see the work we've done so far. This time note down the EndLBA of /dev/mmcblk0p2.

We follow a similar process to create the third partition. Enter n, p, and then 3. For the "First sector" enter the EndLBA we've noted down plus one. We can accept the default for the end sector to go to the end of our SD card.

To make it easy to get the writing off on multiple machines we want to make this partition easily readable. We make it FAT32 to do so. Enter t, 3, b.

With all this done we want to enter w to write the changes.

Reboot before the next steps.

tc@box:~$ sudo reboot

Once you've SSH'd back in.

tc@box:~$ sudo resize2fs /dev/mmcblk0p2
tc@box:~$ sudo mkfs.vfat -F 32 -n eRetti /dev/mmcblk0p3

Setup our output filesystem to mount on boot

tc@box:~$ echo "mkdir /mnt/kindlewriter && mount -t vfat /dev/mmcblk0p3 /mnt/kindlewriter -o rw,umask=000" >> /opt/bootlocal.sh
tc@box:~$ filetool.sh -b

Install Prerequisites

Install tcz using tce-load

tc@box:~$ tce-load -wi screen firmware-rpi-wifi wifi wireless_tools libnl

Install node

tc@box:~$ wget https://nodejs.org/dist/v14.3.0/node-v14.3.0-linux-armv7l.tar.xz
tc@box:~$ tar xf node-v14.3.0-linux-armv7l.tar.xz
tc@box:~$ PATH=$PATH:~/node-v14.3.0-linux-armv7l/bin

Hostapd hasn't been built for TinyCoreLinux 11.x, but we can use the build for TinyCoreLinux 10.x.

tc@box:~$ wget http://www.tinycorelinux.net/10.x/armv7/tcz/hostapd.tcz http://www.tinycorelinux.net/10.x/armv7/tcz/hostapd.tcz.dep http://www.tinycorelinux.net/10.x/armv7/tcz/hostapd.tcz.md5.txt -P /mnt/mmcblk0p2/tce/optional/
tc@box:~$ echo "hostapd.tcz" >> /mnt/mmcblk0p2/tce/onboot.lst

Install Software

Now that we've got those prerequisites sorted, we can install the eRetti software

tc@box:~$ npm install @mattb.tech/kindle-writer
tc@box:~$ node_modules/.bin/kindle-writer-install-home

After running the second command, the system will always start directly into a screen session running the eRetti server.

To configure the device as a Wifi Access Point...

tc@box:~$ echo "/home/tc/start_wifi.sh &" >> /opt/bootlocal.sh

Save all your changes

tc@box:~$ filetool.sh -b

Upgrading

You can grab the latest version just by reinstalling @mattb.tech/kindle-writer. SSH in, start a new window in screen with Ctrl+a Ctrl+c and then run

tc@box:~$ npm install @mattb.tech/kindle-writer
tc@box:~$ node_modules/.bin/kindle-writer-install-profile
tc@box:~$ filetool.sh -b

Name

"eRetti" is a terrible portmanteau of eReader and Olivetti (a brand of typewriter).