Materials part in README

README.md

@@ -1,6 +1,9 @@
 # Pico IIDX - Beatmania IIDX controller
 
 <img src="doc/main.jpg" width="80%">
+<img src="doc/stacked.jpg" width="80%">
+
+<video src="https://user-images.githubusercontent.com/11623830/229287886-d01893c5-04b6-41fc-a178-72c815e28c96.mp4" controls="controls" width="50%"></video>
 
 Features:
 * It's thin, really thin.
@@ -11,18 +14,48 @@ Features:
 * Multiple turntable effects.
 * Many live settings.
 
-<img src="doc/stacked.jpg" width="80%">
-
-<video src="https://user-images.githubusercontent.com/11623830/229287886-d01893c5-04b6-41fc-a178-72c815e28c96.mp4" controls="controls" width="50%"></video>
-
 Thanks to many respectful guys/companies who made their tools or materials free or open source (KiCad, OpenSCAD, InkScape, Raspberry things).
 
 ## Caution
-This is a difficult build. Much more difficult than my previous Pico Popn project: https://github.com/whowechina/popn_pico. Move forward only if you're REALLY interested.  
-I'm still working on this documentation. If you see incomplete things, that's normal.
+This is a difficult build, much more difficult than my previous Pico Popn project:  
+https://github.com/whowechina/popn_pico.  
+I suggest you to build the my Pico Popn first.  
+This Pico IIDX project:  
+* Heavily depends on 3D printing, both FDM and SLA (resin).
+* Requires skills to solder tiny components and thin cables.
+
+Move forward only if you're REALLY interested.  
+
+**This README documentation is still in progress.**
 
 ## HOW TO BUILD
-### Materials
+### Turntable Materials
+* 1x AS5600 hall angular sensor board (23mm\*23mm)   
+ <img src="doc/as5600.png" width="150px">
+* 1x 6mm\*2mm magnet (should be magnetized in radial direction), sometimes comes with the AS5600 board.
+* 1x 61804-2RS deep groove ball bearing (20x32x7mm), normally < 5US$;
+* 3x M4*10mm screws (large flat head is better) and hex nuts.
+
+### Keybard Materials
+* 1x Raspberry Pi Pico.  
+  https://www.raspberrypi.com/products/raspberry-pi-pico
+* 11x Kailh Choc v1 or v2 keyswitches, to get better play feel, 7 of them should be 50g linear.  
+  https://www.kailhswitch.com/mechanical-keyboard-switches/low-profile-key-switches/burnt-orange-switch.html  
+  https://www.kailhswitch.com/mechanical-keyboard-switches/key-switches/kailh-low-profile-switch-choc-v2.html
+* 7x Kailh low-profile stabilizers.  
+  https://chosfox.com/products/kailh-1350-choc-switch-6-25u-stabilizer-set
+* 2x Panasonic 6mm square tactile switch EVQP1K05M.  
+  https://www3.panasonic.biz/ac/e/dl/catalog/index.jsp?series_cd=3473&part_no=EVQP1K05M
+* 1x USB Type-C socket (918-418K2023S40001 or KH-TYPE-C-16P)
+* 11x WS2812B-3528 RGB LEDs or if you want more challenge: 28x WS2812B-1516.
+* 1x 0603 5.1kohm resistors for USB.
+* 2x 0603 10ohm resistor.
+* 5x 0805 1uF capacitors.
+
+### The Cable
+* 1x HDMI cable (ultra slim, diameter < 4mm), at least 50cm in length, we'll cut the HDMI connectors off, so pick a cheap one.
+* 2X Magnetic pogopin connector sets, male and female. PCB side should use 90-degree pins, cable side use straight pins.
+
 ### Step 1 - Buy
 ### Step 2 - Solder
 ### Step 3 - Assemble