ghost in the Prop1

[brittio]

I've designed quite a few props this year that use your prop1 controller, and i have 2 that activate on their own randomly.  I thought maybe their triggers were shorting and causing the props to go.  I've tried shaking the trigger, the box that houses the prop1, and all the wires and I get nothing until i push the button.  I thought maybe it was humidity issue but I have several other prop1's that are not triggering on their own.  Any Ideas?

[ScaryTinker]

What voltage are you running the Prop-1 at?

[brittio]

I have the same style 24v transformer on all of my prop1 controllers.

[JonnyMac]

Do you have SETUP jumper configured on the trigger pin?  A floating input is the surest way to get random triggering.

[brittio]

One prop1 uses your ap-8 and rc-4 so pin6 is my trigger and is the only pin with a setup jumper, it is in the down position.  My other prop1 is using pin7 and I have setup jumpers on both pin6 & 7 in the down position.

[JonnyMac]

There doesn't seem to be anything untoward then.  Can you swap a "ghostly" Prop-1 with another that is well behaved to see if the problem moves or if it's associated with that prop's setup?

[randyaz]

What are you using for a trigger?

[brittio]

sorry..  I haven't had a chance to get over to the haunt to work on it.  i'll try to do that today. 

the trigger is a push button.

[brittio]

Ok....  I swapped one of the ghostly prop1s w/ a brand new never been used prop1, and i still get the false triggers.  Could power fluctuations cause this issue?  That's the only thing I can think of.

[JonnyMac]

Not likely; it's probably something in the wiring.  As much as a pain as it is, you might disassemble then reassembly the wiring connections.

[livinlowe]

You might want to post a schematic, perhaps that will enlighten the problem

[ScaryTinker]

Any chance the power supply is unregulated 24 volt?  That can cause all sorts of wierdness.  Maybe the props that are not malfunctioning provide enough of a load to keep the power supply well behaved. 

[GregH]

I had the same problem with an illusion room within our haunted house using a Prop1, an AP8, and an FC4 to fade the lights from one side to the other (works great! btw).  The Prop1 was triggering when a near by remote controlled relay board was activated that controlled a separate prop located close by.  Not every time, but often enough, the Prop 1 would trigger when you pressed the button on the remote transmitter.  I was completely surprised by this and it drove me nuts.  The only shared circuit between the two props was the AC line and a power strip.  I determined (guessed) that the relay contact and coil EMI from the relay on the remote control receiver board must be enough to create interference in the AC line capable of triggering the Prop 1????  Sound like a good theory anyways.  I solved the problem by having the Prop1 look for an active trigger over a period of 10ms which is all it took.  Anything under 10ms, such as a spike or interference, would be ignored.  I've found that the Prop1 is extremely sensitive to triggering without this added bit of programming and I use it in all my prop1, prop2 programs.  Sometimes 5ms can make a difference.  We have many Prop1's through out the haunted house mixed with relays and valves and all sorts of things being switched on and off, some with multiple relays clicking like crazy and I found this helps.

Example:

StartAgain:

  Tix = 0

LookAgain:

  IF Trigger = No THEN StartAgain   
  Tix = Tix + 1
  IF Tix < 10 THEN LookAgain   


Happy Programming! :)

[JonnyMac]

Debouncing is a good idea, especially in an electrically-noise environment.  Here's how I do it:

Reset:
  tix = 0

Main:
  PAUSE 10
  tix = tix + 10 * Trigger
  IF tix < 250 THEN Main

This uses a little multiplication trick: anything multiplied by zero is zero -- so when the trigger input is off the value of tix gets cleared.  This routine forces the input to be on solid for 1/4 second -- nothing to us humans but an eternity in the microcontroller world.