Arduino_Meter Mini-App

This simple meter macro reads an analog input pin from an Arduino USB device and displays the reading directly in volts. Hitting any key exits the macro.

The K=5.0 / 1023 line assumes that the power supply is exactly 5.0 volts, but you can calibrate the unit for greater accuracy if you can measure the 5 V supply with a separate meter that you trust; just replace the 5.0 with that reading.

Optionally, you can set the Arduino analog reads to use a more-sensitive range of 1.1 volts full scale, by removing the semicolon from the start of this line:

;Port=$(hF0) + "b" + $(h03)   ;Uncomment for 1.1V range

If you do that, you should also uncomment the line near the end of the macro that restores the normal 5V range. (See Set ADC Bits and Voltage Range under DaqPort Arduino Sketch.)

Note, however, that calibrating the 1.1 V range is not so easy, since the Arduino doesn't have a handy terminal where you can read the actual 1.1 V value. Also, the more-sensitive range may pick up more noise.

;<Help=H492D

Posn#0="Ardu"      ;Scan for Arduino
Posn#1=0           ;First match
@_ComDev_Scan      ;Scan COM devices for match

;Port=$(hF0) + "b" + $(h03)   ;Uncomment for 1.1V range

UP=hA0             ;Use Analog pin A0
K=5.0 / 1023       ;Factor, 0-1023 count to volts

UK=0
WHILE.UK=0         ;Wait for any key to exit
    UK=Key?!           ;Get key, if any
    IF.UK=>0           ;Any key hit?
        LoopBreak=2        ;Exit WHILE if so
    ENDIF.
    Port#D1=UP         ;Request analog input
    UA=Port?2          ;analogRead input pin UP
    V=UA * K           ;Convert to volts
    Mtr0=V + " V"      ;Display volts
WEND.              ;Back for next pass
Mtr0=              ;Close meter
;Port=$(hF0) + "b" + $(h01)     ;Restore 5V range
Port#O=0           ;Close COM port

See also DaqPort Arduino Sketch, USB / Serial Communications Port Access, Macro Examples and Mini-Apps