Solar Powered, Zero Buttons E-book Reader

I am a big fan of reading books, so I've decided to make a small contribution to the world of e-readers .

I travel on the train a lot and I needed some reliable reader. That's why I decided to make DIY e-book reader.

Default e-readers have so many needless options. But all you need 99% of time is turn to next page.

E-ink paper don't consume power till you read it without switching. So Eink+solar power is very suitable combination of technologies.

This book doesn't contains any physical buttons. There is accelerometer inside the book and it can recognize your gestures. It can be used in discrete way (to switch page or to switch menu position in both directions), or it can be used in analog way (e.g. to set brightness of the NeoPixel led)

To turn on the book you just move special plastic key in special place. The internal reed switch will be activated and the book will turn on.

This book has some distinctions from the default e-reader and satisfy my needs better.

1. Solar powered (more autonomous)
2. No buttons. (you need to make some effort to switch the page like in real book)
3. Hybrid capacitors (LIC) instead of batteries
4. Sealed / hermetic ( you can use compound+expoxy resin to totally sealed the book and it'll become water proof)
5. More reliable plexiglass case . You can put cup of coffee on it or you can throw it in your backpack and not worry that it will break.
6. Nothing useless in the firmware
7. Open hardware and firmware
8. Eink for reading and small OLED for quick response menu operations

If you have 3 LIC charged to 3.88V you can read about 880 pages (LICs will be discharged to 3.05V)

To convert books you can use pdf2eink

Also you can check github page of this project github

1. Arduino MEGA2560
2. Waveshare E-ink display 5,83” (648×480)
3. FRAM memory
4. OLED display
5. SD-card slot
6. MPU6050 (instead of buttons)
7. Reed switch (turn on/off)
8. Lithium-ion capacitors (LIC) 4x200F (you can use 3 or 4 caps) LIC
9. Solar panel 136x110
10. Buck-boost converter
11. NeoPixel (not necessarily)
12. Other stuff: diode, transistor (2N2222), resistors, etc

Print parts using 3D printer, PETG as material.

You should print 5 parts:

1. Top and bottom edges
2. Side part with placeholders
3. Solid side part,
4. T key

You can find obj files here : https://github.com/fel88/TurtleBook/tree/main/case

sider15mm_3.obj

spacer_1mm.obj

sider_stub.obj

stub_shrinked_3.obj

Also you should cut two piece of transparent plexiglass 2mm (160x120mm) using laser cutting machine.

After printing and cutting you'll get bare case 160x120x15mm

Put 2 long nuts (M2 6mm) inside each side part into special places. Try to tighten two bolts inside each one. Check it tighten freely. Fix each long nut with hot glue gun a little

You need to resolder all parts from modules to the main PCB according to the maps given here (https://github.com/fel88/TurtleBook/tree/main/pcbs)

Eink

Clean internal side of plexiglass and glue Epaper on it (don't forget remove protection sticker ). Then cover epaper screen with flex rubber 1mm in order to protect screen.

Glue main PCB to the rubber. Then plug in ribbon cable from E-screen to the socket

Take 4 wire and solder them to OLED pins. Then solder wires to the main board according pin labels.

Glue Oled to the plexiglass below the e-screen (don't forget remove protection sticker from OLED)

TPS63020

Solder R4 pad to get 3.3V output. Also don't forget to free others pad.

Solder the Collector of 2N2222A transistor to the GND

Solder 2K resistor to the Base of 2N2222A

Take 3 or 4 LIC capacitors. Cut off half of each leg of each capacitor. Prepare 2 wires for each capacitor (for example, black and red) You can use wire cutter (crimper) it is really handy. Then solder wires to capacitor legs.

Use diode 1N5817

There are several options to make charger (overcharge protection):

1. No protection. Just use diode 1N5817 and control charge level manually (unhandy)
2. Arduino micro +INA219+ P-Mosfet - pretty good way , but it requires additional MCU - not good
3. Using AMS1117-ADJ circuit - pretty good way
4. Using something like HY2112 double MOSFET - not tested
5. Other ways - not tested

Take USB-TTL bridge and program main board using Arduino IDE

Orange is reset (RST) pin

Don't forget to turn off reed switch before programming.

Program

In order to load books you can add WiFi module (Wemos Esp8266 V3)

There are several pins on the side of main PCB board, you can solder Wemos Module there

It will disabled all the time and will not consume power energy.

Program

Don't forget to program SPIFFS

Select "wifi" option in main menu in order to activate WiFi AP

Wifi Access point login/password:

ESPap

thereisnospoon

You can connect via WiFi AP (using your phone or laptop) and run 192.168.4.1 in your browser.

PS

In order to fully disable Wemos we should use Level shifter and P-mosfet (Not implemented yet)

Also you can share books between e-books P2P (this feature is not implemented yet)