Prop1 not triggering after I smoked ULN2803

[brittio]

I originally programed and had my Prop1 working properly except for some irritating solenoids.  I was using OUT7 as my trigger input with the jumper in the DOWN position.  After much frustration trying to get the solenoids to work properly I managed to smoke the ULN2803, which I replaced with a ULN2003a. (according to JohnnyMac's "ULN Modifications for Serial Comms" posted on June 14th")  Now I'm using OUT6 as my trigger input, (I did modify my program to reflect this change) but with the jumper in the DOWN position nothing happens when triggered.  When I change the jumper to the UP position the program continues to run until I press my trigger, and will resume once I release the trigger.

What else does it sound like I fried and how do I fix it?

[JonnyMac]

Do you have the trigger connected between P6.W and P6.R?  Based on the behavior you describe, it sounds like you have it connected between P6.W and P6.B -- it that's the case you can change the trigger level in the program, or change one connection back to P6.R and move the SETUP jumper back to DN.

[brittio]

I'm definetly a newbie at this because I'm not sure how to do anything you just described...  How do I know if P6 is w,r, or b?  The way I've been triggering is a switch between the V+ term and the P6 term, but by the sound of it that isn't correct...

[JonnyMac]

First things first: DO NOT connect V+ to anything except solenoids, relays, etc.  If you connect it to any of the input points on the controller you will probably destroy the controller and have to buy a new one.  And the terminals marked OUT0 - OUT7 are outputs only; if you connected a switch between V+ and one of those terminals that would explain why you popped the ULN.

Every pin on the controller has a 3-pin header; above the P7 header is a marking on the board: "W R B"  This marking designates the polatity of standard servo-type cables that we use to connect external devices to the TTL I/O pins.

W	I/O pin (protected with 220-ohm resistor)
R	+5 VDC (from regulator)
B	Power supply ground (same as GND terminal)

This diagram shows a typical application using a normally-open button (e.g., a mat switch) and a couple solenoids.



Please don't hesitate to post questions BEFORE you try things -- we're happy to coach you to success.  And feel free to call any time: 916-616-1658; that phone is never turned off and if I'm near it when it rings, I'll answer it -- no matter what day of week or time of day.

[brittio]

Do I need to buy a special switch to be able to connect to these, or can I buy connectors at Radio Shack?  I was planning on having an actor or maybe a pressure mat trigger this prop...  Is that still possible?

[JonnyMac]

We sell 12" extender cables that plug right into the headers:

  http://www.efx-tek.com/topics/ext_cable.html

These can sometimes be found in hobby shops that specialize in RC control.  Once you have a cable you can cut it in half (gives you to connections) and then connect your mat switch between the white and red wires.  Just be careful not to let the red and black wires get together as this will cause a short.

If you're going to be doing a lot of this stuff you may want to build custom connections; the Prop-1 documentation gives the Molex part number for the female pin header that you can use.

[brittio]

Thanks for all your help!  I'll try connecting my switch the "correct way" and hopefully my prop1 isn't already toast.  Thanks again.

[JonnyMac]

If you connected a switch between V+ and one of the OUTx terminals chances are that the only "victim" is the ULN -- and it's socketed for a reason....