Children's Church "Press Your Luck" or "Whammy Board" HELP

Darin Roberts

Hello. My name is Darin Roberts, and I am the
Children's Pastor at Lighthouse Assembly of God in Melbourne Florida.
···· I had a friend build a random display board (like in the game show "Press Your Luck" aka "Whammy") for our childrens church.· He used your basic stamp (the board says "Board of Education" and at the top says Rev B.·and the stamp says BS2SX)··to create random #s going from 0 to 31, which would make lights randomly bounce around on a 6 by 6 point board (the center 4 boxes are under the Children's Church logo so are inactive - making 32 boxes).· Each box had 8 LEDs around it.· The boys or girls would push an activator button to start the sequence, then push it again to have it stop.· Unfortunately, the builder never got more than 16 of the channels to work, so we sped up the random timer to jump about 4 times a second, making it hard to track so you were never sure that some were inactive.· In the 6 months we used it, we never got this bug worked out.·I have since moved to florida, and in the move, all the bouncing made the component board which hooks your board to the LEDs come unbound.· So I now have a cool parallax basic stamp board, a lot of LEDs, lots of little wires hooked to a lot of resistors, and no board for my ministry.
I contacted tech support today (12-7-05) and they advised me about getting a··DB9 serial cable, plus the links to the 504 page book and the software needed to repair it, but I have no idea what to do next.

I appologize for all of this.· My training is in child psychology and
theology, and my grasp of electronics is very basic, but I am trying to
learn.· Please e-mail at kidpreacher@hotmail.com, or call me at 321-806-9156.

Darin Roberts
www.kidpreacher.org

T&E Engineer

Unless you hopefully have a schematic wiring diagram (how to connect the BS2sx to the rest of the components such as LEDs, etc..) and the original code to work with (saved as a BS2sx file) you may have to start over again from scratch.

Paul Baker

Timothy is correct. Without the orginal code on a disk, you'll have to start over programming it. But first, you'll have to deal with the hardware issue. First, are you able to contact the builder to ask for code and schematics? If not, you'll have to draw out what the circuit is, either by hand or using a program such as the one availible at www.expresspcb.com·. Recreation to the best of your ability of the circuit is nessesary for us to help you. I have a suspicion of why no more than 16 LEDs would light, but without seeing the circuit, I cannot be certain, and trying to explain to someone without electronics experience wouldn't be of any help. A picture could express it, but a word description would just get you lost.

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Darin Roberts

Thank you both for replying so quickly.

I am not able to contact the builder anymore, so I think I will have to start over.·

Though I can not read a schematic by symbols,·I do know how to solder, if someone says to put a jumper from wire b to resistor A, or from the long side of an·LED to ground.· I also have a man in the church who says he can help me build something if he has a schematic to follow.

As to the hardware attached to the BS board, there are 5 chips attached to the project board allong with 32 resistors.· 2 - CD4067BE and 4 - N2803AZ.·

I hope this helps.

Darin Roberts

WWW.kidpreacher.org

·

Paul Baker

Ok the listing of the other chips does help, the CD4067BE chips are analog mux/demux's which is a 16 position switch, since you have 2, thats 32 possible positions. The N2803AZ (more frequently refered to as ULN2803) are darlington transistor arrays, which are used to supply extra power to the LEDs to light them up. Each chip has 8 of them, so 4 chips means 32 LEDs can be driven. His choice of parts is sound, and knocks out my idea of why only 16 lit (though I now have a new suspicion). Can you draw a picture of how all these chips are connected? It is not nessesary to drawn the LEDs, that part is now obvious. I know how the schematic should look, but Id like to see how it actually is connected to see if there is any wiring errors (since you indicated it always had a bug). I can provide a sample schematic of how they should generally be connected (there are actually several valid ways of connecting them), but cannot do so until I get home.

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Darin Roberts

I will try. The builder ordered a little pc board, and has the gold runs on the top and bottom so it will take a while. I also might try to photograph it and upload a picture, but am not sure the photos will have the detail needed. I will try to have it up later this afternoon (5:00 PM Eastern)

Thank you again
Darin

Paul Baker

If you draw it by hand, use a multimeter if·you have one, it can greatly aid finding the connections (put it on the continuity setting, or the lowest range for resistance if there is no continuity setting). This will prevent having to repeatedly turn the board over and over. If you have a flatbed scanner, scan both sides of the board. It will provide better resolution than a digital camera can in macro mode.

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Paul Baker

I can reduce the complexity of the task by telling you what connections I am interested in looking at. I mainly want to know how the CD4067s are connected to the stamp, the pins on the CD4067s that should· be connected are pins 1, 10, 11, 13, 14. The pins are numbered by orienting the notch upwards, the pin to the left is #1, then they count counter-clockwise ending with pin #24 to the right of the notch. I need to know if the pins I listed are connected to individual pins on the stamp or if some of them are shared (both CD4067s pin are connected to the same pin on the B2sx). Also see if pin 15 is connected to the stamp or if it is connected to pin 12 of the CD4067.

The ULN2803 and the LED connections are not important. There is only one way those should be connected.

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Bean

Darin,
If you can do it, I get great pictures by putting my pc boards on a scanner and scanning them.
Bean.

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·

Darin Roberts

Here are the best scans I could get.· I can not tell you how the BSBoard was attached to the breadboard with the 2 chips on it since that is what came loose in transit.· I hope what I have helps.· If we need to start from scratch with just the basic stamp, and go buy new chips and stuff, I am willing.· I just would like to have a working "Zonker" board for my next VBS.

Paul Baker

Yeouch, the field of view on your scanner is attrocious.

I'll see what I can do to decifer the setup. I don't think you'll need any new components, but it may come to ripping out all of the wires for the CD4067BE and rewiring them.

What chip is in the lower right hand side of scan.jpg, Also above that appears to be an empty socket, did a chip fall out, do you still have it? Is it the same as the chip below it?


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Darin Roberts

actually, they are not chips, they were ribbon cable conectors (the positive leads, I think)

I will also be happy to rewire this from scratch if it will make all 32 channels work

I truly appreciate this

Darin

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Paul Baker

Ok I spent some time last night trying to look at the pictures, and ended up throwing my hands in the air. It will be easier to create a new schematic. I already have an idea of how to hookup the CD4067s using a clever trick involving the inhibit pin. I highly doubt this will be the way the original designer hooked up the circuit, which means a rewrite of the program will be nessesary. I had to brush up my resume last night and submit it, so I didn't have time to draw up the schematic. I will try to get to it tonight.

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Darin Roberts

Thank you so much for your help. I will look forward to seeing what you come up with.

Darin

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Paul Baker

Ok heres the start of a schematic like I promised, ask if you need help understanding it. The P0-P5 are connections to the stamp, I dont have an easy way to check the pinout of the darlington arrays at the moment, so I didn't include them. A brief explanation of the CI/O connections, the connection of each is connected to the Inhibit Pin of the other. So whenever the CI/O is high, it disables the other CD4067, so here is the truth table:

P4 P5··· Action

0·· 0···· Both CD4067s are active, but both are outputing a 0 which doesn't turn on any LEDs

1·· 0···· Bottom CD4067 is inactive the output of the top CD4067 is on according to the value on A,B,C,D

0·· 1·····Top CD4067 is inactive the output of the bottom CD4067 is on according to the value on A,B,C,D

1·· 1···· Both CD4067s are inactive -> no LEDs lit

I can give tips on how the darlingtons are connected when I am at a computer that can read pdfs (tomorrow).

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Paul Baker

Ok heres the last hookups, attached is the pinout diagram of the darlington, each output of the analog muxs should be tied to an input of one of the darlingtons, tie Gnd to ground and finally tie each output of the darlingtons to a resistor + LED which is connected to Vdd on the other side, test your LED + resistor for the proper orientation by connecting Vdd and gnd, when you find the connection (there are two possible ways) that lights the LED, leave Vdd connected and tie the ground end to the output of the darlington.

This completes the circuit connections. Now you are ready to program.

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Paul Baker

Well it seems the picture I extracted isn't viewable on all machines heres a link to the pdf I got it from:
http://www.st.com/stonline/books/pdf/docs/1536.pdf

Pin 10 (Common Free Wheeling Diodes) does not to be connected because you are not driving an inductive loads, If you want peace of mind connect it to Vdd (+5V).

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Darin Roberts

Once again, I appreciate all your help.· I will try to build the circut over the next few days.·Thanks

Darin

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