Gadgets - an egg timer

This little beast was a long time in the thinking, and finally got done a few weekends ago. I wanted an egg timer that would be activated by a single press (there is a switch behind the plate with the 6 LEDs); would have an increment increased with the same single button; would remember what it was last set at; and (very important) have minimal power consumption without a dedicated on-off switch. The latter is achieved, as I found with several experiments, very effectively, by lowering the clock frequency of the chip, giving a calculated AA battery life due to the quiescent current of no less than 5 years. Lastly I wanted to put this object into a case where the button was somehow incorporated into the object - and I wanted to 3D print the object, which gave me latitude for unusual shapes. The components are minimalist. The egg timer counts up to six minutes because I wanted to use an O8M2 chip; the 6 LEDs are multiplexed by reversing the polarity. The voltage is important. At 4.5 V results were bizarre because 4.5 exceeds the voltage drop of two red LEDs. 4.5V would be fine for blue LEDs. 

The commented code is below. Times were worked out empirically and are accurate to within a couple of seconds. The main loop is simply a 5 second pause at 31KHz. This is preferable to nap because response to an interrupt, waking the timer, is instantaneous. Upon wake the clock frequency is increased to 4 MHz. Single clicks of the switch (by pushing on the face with the six LEDs) increment the time interval with the number of lit LEDs indicating the time. If the device is then left unclicked for a few seconds, countdown begins from the indicated number of minutes. The LEDs flash to indicate the remaining time on the clock; at the end of the time the device flashes and beeps pleasantly, and then returns to low clock frequency sleep mode. The device can be interrupted during the countdown or the alarm, with another single click.

EEPROM 0,(3)

init:

disableBOD

pinsC=000000

setint 001000,001000

setfreq k31

main:

pause 5000

goto main

interrupt:

setfreq m4

let dirsC=%11110111

settime:

'clicks start at an initial default of 3 min, go up to six and back around to 1

'after the first time use the last value stored in eeprom

read 0, b4

select case b4

case 1

  goto onestart

case 2

  goto twostart

case 3

  goto threesstart

case 4

  goto fourstart

case 5

  goto fivestart

case 6

  goto sixesstart

endselect

threesstart:

if pinC.3=1 then threesstart

b10=0

b1=3

threes:

gosub three

if pinC.3=1 then fourstart

b10=b10+1

if b10>40 then goto countdown3

goto threes

fourstart:

if pinC.3=1 then fourstart

b10=0

b1=4

fours:

gosub four

if pinC.3=1 then fivestart

b10=b10+1

if b10>40 then goto countdown4

goto fours

fivestart:

if pinC.3=1 then fivestart

b10=0

b1=5

fives:

gosub five

if pinC.3=1 then sixesstart

b10=b10+1

if b10>40 then goto countdown5

goto fives

sixesstart:

if pinC.3=1 then sixesstart

b10=0

b1=6

sixes:

gosub six

if pinC.3=1 then onestart

b10=b10+1

if b10>40 then goto countdown6

goto sixes

onestart:

if pinC.3=1 then onestart

b10=0

b1=1

ones:

gosub one

if pinC.3=1 then twostart

b10=b10+1

if b10>40 then goto countdown1

goto ones

twostart:

if pinC.3=1 then twostart

b10=0

b1=2

twos:

gosub two

if pinC.3=1 then threesstart

b10=b10+1

if b10>40 then goto countdown2

goto twos

countdown6:

if b1 !=b4 then write 0,b1

endif

pinsC=000000

for b3=0 to 29

pause 1970

if pinC.3=1 then backtobed

gosub six

next b3

countdown5:

if b1 !=b4 then write 0,b1

endif

pinsC=000000

for b3=0 to 29

pause 1970

if pinC.3=1 then backtobed

gosub five

next b3

countdown4:

if b1 !=b4 then write 0,b1

endif

pinsC=000000

for b3=0 to 29

pause 1970

if pinC.3=1 then backtobed

gosub four

next b3

countdown3:

if b1 !=b4 then write 0,b1

endif

pinsC=000000

for b3=0 to 29

pause 1970

if pinC.3=1 then backtobed

gosub three

next b3

countdown2:

if b1 !=b4 then write 0,b1

endif

pinsC=000000

for b3=0 to 29

pause 1970

if pinC.3=1 then backtobed

gosub two

next b3

countdown1:

if b1 !=b4 then write 0,b1

endif

pinsC=000000

for b3=0 to 58

pause 970

if pinC.3=1 then backtobed

gosub one

next b3

alarm:

for b3=0 to 50

tune C.2, 1,($00,$03, $05)

pinsC=000111

if pinC.3=1 then backtobed

tune C.2, 1,($07,$09, $11)

pinsC=010000

if pinC.3=1 then backtobed

next b3

backtobed:

pinsC=010000

if pinC.3=1 then backtobed

setint 001000,001000

setfreq k31

pinsC=000000

return

'at k31, disablebod

'pause 5000 this config gives 3mv across a 200ohm inline supply resistor

'nap 4 gives 2.8 mv

'at m4 , disablebod

'nap 4 gives 2.8 mv

'pause 5000 gives 110mv!!

'at m4 , enablebod

'nap 4 gives 4.8 mv

'pause 5000 gives 110mv!!

'at k31 , enablebod

'nap 4 gives 3.8 mv

'pause 5000 gives 4 mv

six:

let pinsC=00000001

pause 5

let pinsC=00010110

pause 5

let pinsC=00000010

pause 5

let pinsC=00010101

pause 5

let pinsC=00000100

pause 5

let pinsC=00010011

pause 5

let pinsC=00000000

return

five:

let pinsC=00000000

pause 5

let pinsC=00010110

pause 5

let pinsC=00000010

pause 5

let pinsC=00010101

pause 5

let pinsC=00000100

pause 5

let pinsC=00010011

pause 5

let pinsC=00000000

return

four:

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000010

pause 5

let pinsC=00010101

pause 5

let pinsC=00000100

pause 5

let pinsC=00010011

pause 5

let pinsC=00000000

return

three:

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00010101

pause 5

let pinsC=00000100

pause 5

let pinsC=00010011

pause 5

let pinsC=00000000

return

two:

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000100

pause 5

let pinsC=00010011

pause 5

let pinsC=00000000

return

one:

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00000000

pause 5

let pinsC=00010011

pause 5

let pinsC=00000000

return