[chbot] Components

[Volker Kuhlmann]

LCDs:
The cheapest ones are black text on green background with green
backlight. Very common also is whit text on blue background with white
backlight (can't be read without backlight, the liquid crystal passes
light when on). Any other colours very difficult to get, and expensive.

http://www.aliexpress.com/item/Free-shipping-1pcs-1602-16x2-HD44780-Character-LCD-Green-1pcs-IIC-I2C-1602-Serial-Interface-Adapter/32675304812.html
http://www.aliexpress.com/item/Free-shipping-1602-16x2-HD44780-for-arduino-Character-LCD-w-IIC-I2C-Serial-Interface-Adapter-Module/1935576611.html

1 seller has grey background, white backlight, blue text:
https://www.aliexpress.com/store/133690
https://www.aliexpress.com/item/1pcs16X2-1602-162-LCD-character-LCD-display-module-LCM-backlight-Gray-White-High-quality-Industrial-grade/1897409448.html

Very little description, if you're lucky you get a dimensional drawing
and the controller chip model. For Arduino you need this to be HD44780
or equivalent (there is at least 1 other model number for this chip
too). If it says "for Arduino" you at least get your money back if it
doesn't have that chip.


The nifty little I2C port expander fitting these LCDs uses a PCF8574, or
PCF8574A, which differs in I2C base address only. Default address is
base+7!!
E.g.
https://www.aliexpress.com/item/Free-Shipping-2PCS-IIC-I2C-Interface-LCD-1602-2004-LCD-Adapter-Plate-for-Arduino/32277096713.html
Often it's already included with the display. Makes wiring up MUCH
easier.

Arduino software:
http://playground.arduino.cc/Code/LCD
Most libraries either no good or pretty bad, but this one works:
https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home
Even with doxygen documentation, but it still has bugs.
Oh yeah, before you unpack the multimeter, the magic incantation is
  LiquidCrystal_I2C lcd(I2C_ADDR,2,1,0,4,5,6,7,3,POSITIVE);
The backlight is powered through a jumper, pulling that off allows to
feed an Arduino PWM output in.
All the I2C LCD libraries have to be used instead of the Arduino
built-in one. Annoyingly they use the same name so it's either or.


Night light software:
http://volker.top.geek.nz/arduino/

Component examples (there are many other sellers for the same things):

LED ring:
http://www.aliexpress.com/item/5050-12-Bit-RGB-LED-Ring-WS2812-Round-Decoration-Bulb-Perfect-For-Arduino-Promotion/32651769445.html

Arduino Pro Mini, 16MHz, ATmega168
https://www.aliexpress.com/item/Pro-Mini-Module-Atmega168-5V-16M-For-Arduino-Compatible-With-Nano/32676023781.html
You must have 16MHz for WS2812 LEDs, 8MHz is too slow for the LED clock.
16kbyte is enough, but it doesn't quite fit into an 8kbyte digispark.

Voltage regulator, with capacitors etc
https://www.aliexpress.com/item/Free-Shipping-5PCS-LOT-5V-power-supply-module-AMS1117-5-0-AMS1117-5-0V-power-supply/1804554424.html

Rotary encoder
https://www.aliexpress.com/item/Rotary-encoder-with-switch-EC11-Audio-digital-potentiometer-20mm/32661294919.html

PIR
http://www.aliexpress.com/item/Hot-10pcs-lot-Adjust-Infrared-IR-PIR-Motion-Sensor-Detector-Module-Security-Motion-HC-SR501/968259823.html


-- 
Volker Kuhlmann
http://volker.top.geek.nz/	Please do not CC list postings to me.