TripWire Module

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#1

Over the past several months, I’ve found myself manually building the same circuit for my last two projects - the arcade and my internet connected mouse trap which hasn’t been released yet due to DHCP bugs. For the arcade, I needed to connect external buttons & joystick (Hydra Kiosk Kit) to the Hydra and for the mouse trap, I need to detect a break in a wire. These are basically the same problem and I didn’t want to ever have to take the time to throw it together again so I created the TripWire Module.

It allows for seven external switches or any other device that simply needs to detect an on/off state. There are LEDs for every switch that light when they are grounded. Four of the pins are made to allow male spade terminals for easy connection to the Kiosk kit or other external devices. All pins have ESD protection and should supply sufficient protection against devices connected via longer wires (such as is needed for mouse traps…).

These pictures are of my latest revision which is fully functional but still has few things that need fixing - primarily silk screen related. It seems that I was a beta tester for a new process at DFRobot… Also, I designed the circuit so that the LEDs could be enabled/disabled via solder junction to save power if needed (especially useful if you would be using it in a normally on state). Unfortunately, it seems that they aren’t disabled by default. I’m going to start looking over the board for defects but please look at my schematic and see if I did something dumb also.

I’ll probably do one more revision just because I want it perfect. Let me know if there’s anything you would change about it and I’ll incorporate it in. If anyone is in need of one of these now and can’t wait for the final revision, let me know. I have 50 of these… I’m hoping DFRobot is going to at least discount the next run since it seems it’s their fault that the keep away circles didn’t print.

The second photo is of the tiny ESD protection diode array. The part is at the tip of the toothpick. The pad is just below it.

5 Likes
#2

@ ianlee74 - nice work lan :slight_smile:
it is surprising how simple some of small packages are to flow
did you check your gerbers in cam350? I thought i had a similar issue…sure enough they were missing from my layout…oops

#3

Thanks. No, the files are fine. Lauren has confirmed that I found a bug in their manufacturing process.

#4

@ ianlee74 - im sure he will sort you out, now onto the next one!

#5

Looks good! And seems very useful, too.

#6

This one was to fulfill a need. The next one is going to be for fun. You’re going to really like it. It’s right up your alley. :smiley:

#7

@ ianlee74 - the old module tease trick! Get cracking then :smiley:

#8

Nice module. Good job!

#9

Oh nice idea Ian ! I need one of this …

#10

That’s a really nice looking module. Great idea.

#11

@ ianlee74 - Neat module. The 3V3 is backwards on the bottom side. :slight_smile: Surprised the board house did not fix that for you automatically.

#12

Thanks, guys.

Yea, that would have been nice… DFRobot is great to work with but it’s been my experience so far that they won’t modify your designs in any way once they’re received. Did you notice this??? I expected they would replace my text :smiley:

#13

@ ianlee74 - Oh wow. Here you take the time to tell them where they can put the code and they still put it where they want. At least they were close to it. :slight_smile:

#14

@ patc - “: )” “: D” “: whistle :” - etc with no spaces or "

#15

@ patc - your welcome :wink:

#16

Guys, I’m having a heck of a time tracing down the flaw in my design that is causing my LEDs to light even when my LED_EN jumper isn’t bridged. So, I’m having a contest to help enlist some help. I want to try and get my next revision off for manufacturing no later than this weekend. The person who finds the bug gets a FREE TripWire module!

A picture of the schematic is on the original post or you can download my latest Eagle files here:

I’m sure I’ve done something noobish but I fear that I’ve just spent too much time looking at this thing over the past month and I need some fresh eyes. Thanks for any and all help!

Also, if anyone has any requests for enhancements in the next revision let me know soon.

Also… Before I go reinvent the wheel… Can someone point me to an OSHW Eagle part that wraps a corner hole?

#17

@ ianlee74 - what you mean about the corners?

if no one finds the issue i will have a look when i get into the office in an hour or so…

#18

Are you using a Spider or Cerb for testing?

I think the Gadgeteer socket is powering your LED’s…

e.g. D1 > R3 > R6 > D2 > R5 > Diode array > Pin 5

On a Spider the pins will be floating at around 2.2v and on a Cerb around 0.2v

#19

Sorry, Justin, I’m not following you. I understand that they could be powered through the pin but the 3V3_B net should be open unless it’s soldered to the 3V3 net which is not the case. Are you seeing where the other side of the positive side of the LED is connected to a power source?

#20

Unless i am being really blonde (quite likely) you can trace the juice for D1 back to the socket via the path i mentioned…