The program is implemented as a loop which starts by measuring the photocell input voltage. It is a photo-resistor connected to Vdd, and a 15 kilohm resistor to Vss. If the voltage exceeds an upper threshold then the blue pairing LED lights and the dial light is extinguished. If the voltage is less than a lower threshold then the blue pairing LED goes off and the dial light goes on. The thresholds are loaded as constants for tailoring.

#rem Blue_LED.bas    

Subsystem for GE 1941 radio bluetooth speaker to operate a blue LED when paired

The dial light turns off when paired

John Saunders 10/24/2016

#endrem

#picaxe 08M2

'Input port

symbol Photocell_Port = C.4    'Light makes higher voltage, 15 kilohm pulldown

'Output ports

symbol Dial_Port    = C.2    'High provides 40 MA to two dial lights

symbol LED_Port      = C.1    'High provides 10 MA to the blue LED

'Constants

symbol On_Threshold   = 150    '> Enables pullin

symbol Off_Threshold  = 75    '< Drops out

'Variables

symbol Photocell      = b2    'Analog photocell input

init:

SETFREQ m4

LOW LED_Port

LOW Dial_Port 

main:

READADC Photocell_Port,Photocell

IF Photocell > On_Threshold THEN

    LOW Dial_Port

    HIGH LED_Port

ENDIF

IF Photocell < Off_Threshold THEN

    LOW LED_Port

    HIGH Dial_Port 

ENDIF

PAUSE 100

GOTO main