RGB LCD Shield Application (ID: 715)

[adafruitandy]

RGB LCD Shield Application (ID: 715)

Can I discard or not use the 16x2 RGB LCD and use a 20x4 LCD (ID:498) on the RGB shield?

I know this LCD is bigger than the 16x2 but I am only going to remote mount it a
few inches with all 18 wires connected from it to the 18 holes on the RGB LCD shield (ID:715).

On the shield, I am only going to only use I2C and tac switches and not the Arduino headers.

The software should work ONLY by just modifying lcd.begin(16,2) to lcd.begin(20.4)?

Both the hardware and software should then work?

Am I missing anything in the RGB Shield application modification?

[adafruit_support_bill]

Yes to all questions but the last one.
The only caution is on the length of the leads to the remotely mounted display. A few inches should be OK.

[adafruitandy]

Hardware: RGB shield with 4x20 RGB LCD
Libraries: Adafruit_RGBLCDShield Adafruit_MCP23017

Just curious, is there any way to shut off the backlight completely for low power operation?

There are commands lcd.display(), lcd.noDisplay() and
lcd.setBacklight(), but nothing for turning off the backlight completely
to reduce power by 60 ma. ?

Quote from assembly instructions

Writing Your Own SketchesThe Adafruit_RGBLCDShield library is a derivative of the LiquidCrystal library that comes with Arduino so you can call any of the functions that you're used to and they'll work just the same.
There are two extra functions you mway want to use. One is lcd.setBacklight(color); which will change the backlight color assuming you have an RGB LCD on. At this time, the library does not do any PWM on the RGB backlight, so you can select from 8 different colors (inlcuding OFF) - if you place these #define's at the top of your sketch you can simply call whichever color you want to appear.

edited ... spelling

BTW ... #define OFF 0x00, in the library, for setBacklight(0) - thks Adafruit

[adafruit_support_bill]

setBacklight(0); will turn it off.

[adafruitandy]

Project update ...

I like to point out that the 4x20 is, of course, larger than the standard 16x2 LCD that fits on this shield. I used
a 18 pin female 0.10 space socket on the shield board to mate to the larger 4x20 LCD. Some nylon spacers and hot glue wasused between both boards for support. Note: the larger LCD blocks the tact switches from being used!

Since the tact switches were not accessable when using the panel mounted larger 4x20 LCD with the shield, I used Adafruit's tact switch navigation joystick to supply the proper inputs to the shield. On the back of the shield, I installed the I2C 4.7K pullup resistors, in case they had to be changed for different configurations and I also soldered the LCD contrast pot on the back so I could easily adjust the LCD contrast. As you can see, I hacked this shield to death for to meet our project's special requirements but in doing so brought up a new product idea for Adadruit. A standalone RGB LCD controller with tact "joystick navigation. Another addition would be to add an I2C digital pot or PWM to control the contrast from the user's microcontroller?

BTW ... Adafruit and especially Limor Fried would be extremely proud of our project because we used over a dozen high tech parts from Adafruit without which our project would never be completed!

Here is a short listing ... Adafruit plug ...
Alpha Clock Five kit https://www.adafruit.com/products/620
LCD I2C shield with 5 tact switches replaced by tact joystick (hacked or modified) http://adafruit.com/products/715
RGB backlight negative LCD 20x4 (modified to fit 2x16 LCD shield) https://www.adafruit.com/products/498
Ultimate GPS (modified-remote mounted fix LED) http://adafruit.com/products/746
+5 VDC to 3 VDC level converter (for I2C LCD) http://adafruit.com/products/757
INA219 High Side DC Current Sensor Breakout http://adafruit.com/products/904
Electrc IMP SD WiFi card (modified for network time and status) http://adafruit.com/products/1129
Tact joystick (modified for LCD display) https://www.adafruit.com/products/504
CR2032 battery holder(s) (Standardize battery holder for all lithium backups) https://www.adafruit.com/products/653
Spring loaded terminal blocks for 5 V bus bar https://www.adafruit.com/products/1074
Protoboard for 5 V bus bar https://www.adafruit.com/products/589
Panel mount power connector 2.1 mm https://www.adafruit.com/products/610
Teensy 3 ARM Stamp http://adafruit.com/products/1044

In our "DoomsDay Atomic Alpha Clock Five Project" we used a Ultimate GPS, a WiFi Electric IMP (network time), a WWVB Atomic radio receiver, two precision TXCO real time clocks (+- 2 PPM SPI DS3234 and I2C DS3232) and two microcontrollers - (Teensy 3 ARM stamp & Arduino 328P clone). We then use the three precision clock sources (UNIX seconds) to drive or sync to the Evil Mad Scientist huge, very bright, "Alpha Clock Five" 2.5" clock display.

Project link....
http://forum.pjrc.com/threads/17369-Doo ... e-Teensy-3

[adafruit_support_bill]

Very nice looking clock!

[adafruitandy]

Updated project image ...