Nuts & Volts - September 2004

Project

Figure 6

Figure 7

Tub Construction

‘————————————————————-
‘ Generate the light
‘————————————————————-
pwm:

random 40,rnd

rnd = rnd + 5

‘This will determine how long
‘we stay with a color
‘With a minimum of five counts

‘To create the six PWM signals we turn all ports on
‘then turn them off as each color count is reached.
for cycle = 1 to rnd
configio 0,1,2,3,4,5
 for curcount = 1 to maxcount
  if curcount = bluecount then
   gosub offblue
  endif
  if curcount = redcount then
   gosub offred
  endif
  if curcount = greencount then
   gosub offgreen
  endif
 next
next
return

The actual tub construction is very simple. Using a Rubbermaid #5193 tub, simply set the battery and circuit board assembly into the tub with the LEDs facing up, as shown in Figure 6.

This is a one pint container and the battery holder centers pretty well without much effort. If you use a different size tub or battery layout, you will have to make sure the assembly is centered so that the tub does not tilt to one side.

In order for the lights to illuminate the pool bottom, you need to reflect the LEDs downward. I have used several reflectors, such as compact mirrors or convex mirrors. Out of all the tests, aluminum foil seems to work the best at reflecting the light because all the little crinkles tend to mix the colors more evenly. You can use double-sided foam or tape to attach the foil to the inside of the lid. Make sure the shiny side is down, as shown in Figure 7.

That is pretty much it for the tub construction. You can add some flowers or a rubber ducky to the top of the tub, if you wish.

How Well Does It Work?

‘You may want to place this code directly in the if
‘statements. The KRcompression technology built into
‘the Athena engine is centered around modular code so
‘this particular way is more efficient than single if
‘ statements

My wife loves them and can’t wait for the long, hot days of summer. My hard-to-impress daughter wants the five units I made to be used at her next pool party.

I’m getting over 12 hours of use out of the lights, so my next step is to add a small solar cell to charge the batteries during the day.

Be sure to visit Kronos Robotics at www.kronos robotics.com for project updates, as well as more light patterns. NV

Sources

F o r

E l e c t r o n i c s

NUTS & VOLTS E v e r y t h i n g

‘Port Handlers
offblue:
  input portblue2
  input portblue1
  return
offred:
  input portred1
  input portred2
  return
offgreen:
  input portgreen1
  input portgreen2
  return