Arduino LCD shield with buttons.

[Mario Zandel]

Hi Guys. I decided to have a go at using an Arduino uno. I have an LCD shield with 5 buttons on it. I have had the LCD screen print test messages, but i a m having trouble getting what I want to work. There are 5 buttons on the shield, connected to Analog_0 with various voltage dividers. I have worked out their values. Select, 721 : Left, 479 : Down, 306 : Up,131 : Right,0.
What I wanted to do was to display the button being pressed and have it latch until another button is selected. Here is the code
~~~

chip mega328P, 16

#option explicit
#include <uno_mega328p.h>
;setup Lcd Parameters
#define LCD_IO 4
#define LCD_NO_RW
#define LCD_Speed SLow
#define LCD_DB4 DIGITAL_4
#define LCD_DB5 DIGITAL_5
#define LCD_DB6 DIGITAL_6
#define LCD_DB7 DIGITAL_7
#define LCD_RS DIGITAL_8
#define LCD_ENABLE DIGITAL_9
#DEFINE LCDBacklight DIGITAL_10
DIM BTTNPUSH AS Word</uno_mega328p.h>

; MAIN PROGRAM
WAIT 2 S
set LCDBacklight on
PRINT " PRESS A BUTTON"
Do Forever
BTTNPUSH = READAD12(ANALOG_0)
Select Case BTTNPUSH
Case < 50
CLS
PRINT "RIGHT"

 Case > 150 & BTTNPUSH < 350
  CLS
  PRINT "UP"
 Case > 350 & BTTNPUSH < 500
  CLS
  PRINT "DOWN"
 Case > 500 & BTTNPUSH < 700
  CLS
  PRINT "LEFT"
Case > 700 & BTTNPUSH < 900
  CLS
  PRINT "SELECT"

End Select
LOOP
~~~

Any Ideas what I am doing wrong?

Thanks.
Marz

edit: Added ~~~ tags to assist code readability

[Chris Roper]

You did not say what the failure is in your code, i.e. what is it doing that is not expected?
As I don't have your hardware setup so I can't test your code myself but two suggestions spring to mind from reading it.

1) What happens if the ADC Reading is > 900? May I suggest you have a Case Else To catch any unexpected values.

2) Take a look at the SCALE() Function it may suit your application better than a Select Case Construct.

Cheers
Chris

[mmotte]

Marz,
The problem is the READAD12, it should be READAD10.
also I had to edit the ranges slightly. But it works on mine.

#chip mega328P, 16
 #option explicit
 #include <UNO_mega328p.h>
  ;setup Lcd Parameters
  #define LCD_IO 4
  #define LCD_NO_RW
  #define LCD_Speed SLow
  #define LCD_DB4             DIGITAL_4
  #define LCD_DB5             DIGITAL_5
  #define LCD_DB6             DIGITAL_6
  #define LCD_DB7             DIGITAL_7
  #define LCD_RS              DIGITAL_8
  #define LCD_ENABLE          DIGITAL_9
  #DEFINE LCDBacklight        DIGITAL_10
  DIM BTTNPUSH  AS Word

; MAIN PROGRAM
   WAIT 2 S
   set LCDBacklight on
   PRINT " PRESS A BUTTON"
   WAIT 2 S
 Do Forever
    cls
   BTTNPUSH = READAD10(AN0)
   Print BTTNPUSH
  Select Case BTTNPUSH
     Case < 50
      CLS
      PRINT "RIGHT"

     Case > 140 & BTTNPUSH < 300
      CLS
      PRINT "UP"
     Case > 301 & BTTNPUSH < 500
      CLS
      PRINT "DOWN"
     Case > 500 & BTTNPUSH < 700
      CLS
      PRINT "LEFT"
    Case > 700 & BTTNPUSH < 900
      CLS
      PRINT "SELECT"
  End Select
  wait 2 s
 LOOP

BR
Mike

[Anobium]

and, there is a demo that also shows this. Some of the clone LCD will damage your chip. if you do not modify. This information is also in your demo folders.

[Mario Zandel]

Thanks everyone for your replies. I did have it with READAD10 at one point but not latching the button push. As usual I didnt think to keep the different iterations of what I did so I could back up to something close to working. Dont know why I changed to READAD12. Probably just a typo that i just kept doing. @mmotte The pin is active high when no button pushed. I did have an else statement to cover that to do nothing, but again It went missing in the constant code changes trying to get it to work. Thanks again everyone.
Marz.