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OS Wig-Wag Project

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nuckolls.bob(at)aeroelect
Guest

Posted: Wed Apr 18, 2012 8:42 am Post subject: OS Wig-Wag Project

I'm ready to lift the lid on my contribution

to date. The data package is available at:



http://tinyurl.com/7885bd6



Anyone who enjoys . . . and is capable of sifting

the drawings through the sieve of logical

agreement between the data points is welcome

to do so. Critical review welcomed.



I've included a couple of LEDs on the board

that will emulate the fixtures in the airplane.

This will allow any software developers to

hook a switch and 12v power supply to the board

and exercise the fruits of their efforts

on the bench.



I'll take another pass at the 'sieve' tomorrow

and maybe get some boards on order. I have all

the parts.



   Bob . . .

gregmchugh

Joined: 03 Apr 2012
Posts: 42

Posted: Thu Apr 19, 2012 6:28 am Post subject: Re: OS Wig-Wag Project

Bob,



Looks good for what I would need for a wig-wag...



Here are some possible typos I think I picked up...



On page 2 the processor part number is listed wrong.

On page 3 at the top right I think that it should read P-1, not P-11.

On page 3 Pin 6 of the micro is being used as GP1 in this application.

On page 3 Pin 7 of the micro is being used as GP0 in this application.



and a couple of questions...



1. Pin 12 on the d-sub connector seems to be unused but also shown

differently than the other pins on the page 1 drawings. Is this

a convention of some sort?



2. Looking at the PIC12F683 data sheet there are some confusing

instructions on using MCLR with Power on Reset but I think that

Pin 4 could be left unconnected for this application or

used for another purpose since there is no external reset circuit.

What is your reading on this?



3. Not sure how much real estate is left on the board but with Pin

4 freed up and Pin 3 unused you might be able to add the Under Voltage

module functions into this module. Connect one pin as an A/D to

read the bus voltage and use the other pin to drive the warning

LED using a spare d-sub pin. Maybe also figure out how to handle

the relay control for the aux battery. Maybe this is something for

the next spin of the board...



As it is, it meets my needs for a wig-wag module but I can see a software

option that might be useful for users with other configurations of lights.

In my case I have two landing lights on the wing and really only need

to have them both off, both on, or the wig-wag. If other users have

a Taxi light and a Landing light they may want to be able to have

an alternate control function that allows: All Off, Taxi On, All On, &

Wig-Wag (or some variation of four different states). Changing the

function of the switch as shown to handle Off, Taxi, All On and then

adding a second switch to ground both inputs for Wig-Wag would

allow this to be done with only a software change needed to implement

in the module. An option for those who would want it...



It may be little early to be looking at Version 2 of the module but I will

throw out a couple of items that might be useful to consider that require

more than a minor spin on the board.



1. Allow for drop in of a PICAxe 8 pin module. This would require

realigning Pin 2 and Pin 7 to handle the Serial In and Out for the PICAxe

configuration and moving the current functions to other pins. Two resistors

are the only added components for the PICAxe serial I/O circuit. Pin 7

can be reconfigured as a regular I/O pin in the application or left

to handle Serial Out (maybe to a remote display?). With Pin 2 and

Pin 7 brought out to the d-sub you would have the capability to

connect to the PICAxe tools and do serial communication with the chip

in the application via the d-sub.



2. In-Circuit Programming of the PIC is something that might be useful

when using the standard PIC chip. Not sure about the need for it...



3. As I noted above, an easy add-on for the current module would

appear to be the functions handled by the Under Voltage module

(warning light and aux battery control).



I expect that others have already come up with more ideas for

using the module. With digital I/O, analog inputs, and a serial

interface there a lots of possible functions for the module even with

only an 8 pin micro.



Lots of options, which is good...



I will be continuing work on a software version to handle the

basic wig-wag function in the next few days. Should have

an initial version available within a week or so.



Greg McHugh

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Apr 19, 2012 6:46 am Post subject: OS Wig-Wag Project

 	  Quote: 	
		  I'll take another pass at the 'sieve' tomorrow

 and maybe get some boards on order. I have all

 the parts. 	


   Some background on the decisions that went

   into satisfaction of design goals:



   I started with the following ideas for

   crafting the configuration I published:



   1. Use the already developed package based

   on Polycase enclosure and D15 connector. I

   have cases and lids already cut to accept the

   connector. Of course, this sets the boundaries

   on the ECB.



   2. Use simple on-off-on toggle switch to achieve

   OFF-WW-ON control functionality. Easily handled

   with software logic.



   3. Minimum parts count.



   4. Minimum variety of parts.



   5. Maximize heat-sink copper for the FETs



   6. Add some functional indictors for

   as-development tools (a couple of LEDs)

   so that bench testing of software needs only

   a switch and power supply.



  ----------------



   Parts selection was pretty easy. As one

   can see from the schematic, all resistors

   and capacitors are the same value. This

   makes it easier to order, stock, and

   install with minimized error. The only

   parts that required any "calculation for

   performance" was the voltage divider for

   the power supply (exact value not critical

   and they only needed to be equal). And

   the series resistor for the shunt regulator.

   The calculated optimum value could be achieved

   by paralleling 4 of the common bill of materials

   value. 4.99K / 4 gives us about 1200 ohms

   at better than 1 watt because the heat doesn't

   come out of a single device . . . but is spread

   over larger area.



   The other values go to transient immunity.

   Two standard practice bypass capacitors on supply

   rails, two capacitors and two transorbs

   protecting fragile silicon from stuff conducted in

   on the ship's wiring.



   This is a good example of what my cohorts

   at HBC called a "cotton ball" . . . very

   non-critical components (tells us that

   drifts in performance due to component 

   tolerance/drift are insignificant). The

   thought processes that go toward component

   selection are pretty ho-hum.



   Not to take away from the ultimate

   functionality of the assembly. Once the

   silicon is safely wrapped in environmental

   cotton, the magic poured into the source

   code is relatively unrestricted.



   A similar philosophy was adopted for the

   'do-lots' board from which this project

   evolved. Figure out a way to wrap an 8-pin

   PIC up in a deep sea diving suit and then

   teach it how to sing, dance and do dishes.



   I'll order boards today. As Eric mentioned,

   ExpressPCB doesn't fuss about what is on a

   miniboard (3 pieces returned in 3 days for

   $70). Each mini-board will give us two

   finished boards with a couple of avionics

   ground bus boards thrown in on the side . . .

   sorta like this:



 [img]cid:.0[/img]



   So we'll end up with 6 boards for the development

   work at a cost of just over $11 each and turned

   around in 3 days. If I sell some avionics grounds

   with the 'residuals' then the out-of-pocket development

   costs go down.



   Folks interested in doing software for this 

   project need to chime up. I'll provide an

   assembled board with a control switch attached.

   You'll need a 12v source (2 el-cheapo WalMart

   lantern batteries?) and a development system

   of your choice. I'll throw in a couple of

   PIC chips and install a socket on the board

   for ease of swapping the chip between programmer

   and the end product demonstration.



   It's my vision for this project to publish all

   the drawings, ECB source files, and software

   sources which anyone can use to carry this

   project (or perhaps another functionality on

   the same hardware) forward. Of course, most

   individuals accessing this data have no interest

   in evolving/building their own. But this could

   lay the ground work for others to cultivate

   their own ideas for other products in a garden

   we've already planted with expertise contributed

   from a family of participants.



   That's what Open Source is all about . . .



 

   Bob . . .

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enginerdy(at)gmail.com
Guest

Posted: Thu Apr 19, 2012 7:31 am Post subject: OS Wig-Wag Project

In that case, maybe consider dropping a Open Source Hardware logo in the copper...

http://freedomdefined.org/OSHW



http://oshwlogo.com/



[quote]

   It's my vision for this project to publish all

   the drawings, ECB source files, and software

   sources which anyone can use to carry this

   project (or perhaps another functionality on

   the same hardware) forward. Of course, most

   individuals accessing this data have no interest

   in evolving/building their own. But this could

   lay the ground work for others to cultivate

   their own ideas for other products in a garden

   we've already planted with expertise contributed

   from a family of participants.



   That's what Open Source is all about . . .



 

   Bob . . .  

[b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Apr 19, 2012 8:11 am Post subject: OS Wig-Wag Project

At 10:25 AM 4/19/2012, you wrote:

  	  Quote: 	
		  In that case, maybe consider dropping a Open Source Hardware logo in the copper...



  http://freedomdefined.org/OSHW



 http://oshwlogo.com/ 

 	


  Interesting! Hadn't seen that before. I'm

  not ExpressPCB has a feature that would

  allow us to craft that exact symbology

  onto the board . . . but certainly documents

  that accompany the package could included

  it. I'll see what I can do.



 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Apr 19, 2012 8:14 am Post subject: OS Wig-Wag Project

At 09:28 AM 4/19/2012, you wrote:

 	  Quote: 	
		  


	


   Good input. Give me a day or so to get the disagreements

   sifted and consider the broader options.



   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Apr 20, 2012 10:49 am Post subject: OS Wig-Wag Project

At 09:28 AM 4/19/2012, you wrote:

 --> AeroElectric-List message posted by: "gregmchugh" <gregmchugh(at)aol.com>



 Bob,



 Looks good for what I would need for a wig-wag...



 Here are some possible typos I think I picked up...



 On page 2 the processor part number is listed wrong.

 On page 3 at the top right I think that it should read P-1, not P-11.

 On page 3 Pin 6 of the micro is being used as GP1 in this application.

 On page 3 Pin 7 of the micro is being used as GP0 in this application.



     Yeah, I had a number of loose ends dangling out. I've

     updated the data package with more organized Bill of Materials

     and some expanded information.



  http://tinyurl.com/6lh769o



 

 and a couple of questions...



 1. Pin 12 on the d-sub connector seems to be unused but also shown

 differently than the other pins on the page 1 drawings. Is this

 a convention of some sort?



    Fixed that.



 

 2. Looking at the PIC12F683 data sheet there are some confusing

 instructions on using MCLR with Power on Reset but I think that

 Pin 4 could be left unconnected for this application or

 used for another purpose since there is no external reset circuit.

 What is your reading on this?



    Yes, when configured for reset input, there's a built in   pull up resistor . . . if we left that pin un-used, then   the programmer could set that pin's function to serve   as a reset with no connection and no pull-up needed. However,   the next iteration of the design uses pin 4 as an general   purpose input so the pull up is needed,



 [img]cid:.0[/img]



 3. Not sure how much real estate is left on the board but with Pin

 4 freed up and Pin 3 unused you might be able to add the Under Voltage

 module functions into this module. Connect one pin as an A/D to

 read the bus voltage and use the other pin to drive the warning

 LED using a spare d-sub pin. Maybe also figure out how to handle

 the relay control for the aux battery. Maybe this is something for

 the next spin of the board...



    Your suggestion sparked some consideration of making this   board capable of doing the functions presently proposed for   the 9024 4-function module. 

    By removing two pull-ups 11 and 14 and adding two divider   resistors 26 and 27, these inputs can be shifted from   discrete commands to analog inputs. By taking pins 4   and 3 out to the d-sub connector, the user selection   of functionality can be accomplished the jumpers in   the plug.

    I've added another dash number to the ECB assembly to   reflect this potential. I'll suggest we leave the   4-function module on the back-burner until the   current wig-wag design is gelled . . . but I'm    considering putting the 4-function module into the   Open Source program too. It would be nice to get   that product into the catalogs and this seems like   the shortest path to that goal. As it is, it meets my needs for a wig-wag module but I can see a software

 option that might be useful for users with other configurations of lights.

 In my case I have two landing lights on the wing and really only need

 to have them both off, both on, or the wig-wag. If other users have

 a Taxi light and a Landing light they may want to be able to have

 an alternate control function that allows: All Off, Taxi On, All On, &

 Wig-Wag (or some variation of four different states). Changing the

 function of the switch as shown to handle Off, Taxi, All On and then

 adding a second switch to ground both inputs for Wig-Wag would

 allow this to be done with only a software change needed to implement

 in the module. An option for those who would want it...



    I considered that . . . but consider that the target   system is LED replacements for incandescent lamps   with larger demands. There doesn't seem to be much   value in being able to select individual landing/taxi   lights. Having both on when using benefits of one   didn't seem to be much of a feature.

 



 It may be little early to be looking at Version 2 of the module but I will

 throw out a couple of items that might be useful to consider that require

 more than a minor spin on the board.



 1. Allow for drop in of a PICAxe 8 pin module. This would require

 realigning Pin 2 and Pin 7 to handle the Serial In and Out for the PICAxe

 configuration and moving the current functions to other pins. Two resistors

 are the only added components for the PICAxe serial I/O circuit. Pin 7

 can be reconfigured as a regular I/O pin in the application or left

 to handle Serial Out (maybe to a remote display?). With Pin 2 and

 Pin 7 brought out to the d-sub you would have the capability to

 connect to the PICAxe tools and do serial communication with the chip

 in the application via the d-sub.



    I looked into using 2 and 7 as program select pins instead   of 5 and 4. Problem is that pin 5 could substitute for   pin 7 because they both have GP i/o and A/D. However, 4   cannot interchange with 2 because it doesn't offer any   output.  A PICAXE compatible version could be crafted   if we gave up one of the HexFets.  

 



 2. In-Circuit Programming of the PIC is something that might be useful

 when using the standard PIC chip. Not sure about the need for it...



 3. As I noted above, an easy add-on for the current module would

 appear to be the functions handled by the Under Voltage module

 (warning light and aux battery control).



    Yup, I think the P2 version of the data package will    accommodate that idea.

 



 I expect that others have already come up with more ideas for

 using the module. With digital I/O, analog inputs, and a serial

 interface there a lots of possible functions for the module even with

 only an 8 pin micro.



 Lots of options, which is good...



 I will be continuing work on a software version to handle the

 basic wig-wag function in the next few days. Should have

 an initial version available within a week or so.



    Okay, peek at P2. I've got some work to do in Wichita   this weekend. I'll take a copy to pray over with   a target for ordering boards on Monday

    Bob . . .

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gregmchugh

Joined: 03 Apr 2012
Posts: 42

Posted: Sun Apr 22, 2012 6:33 am Post subject: Re: OS Wig-Wag Project

Bob,



Took a look at the P2 version and it looks good. Only noticed an issue

on page 3 with the d-sub pins. Pin 11 is listed twice (one should be

Pin 10) and Pin 2 is missing (2nd line to the power bus).



I will use the P2 to continue with the software for the wig-wag. I should

have something available later this week to use for testing with the

hardware.



Greg McHugh

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Apr 23, 2012 6:07 am Post subject: OS Wig-Wag Project

At 09:33 AM 4/22/2012, you wrote:

 	  Quote: 	
		  



Bob,



Took a look at the P2 version and it looks good. Only noticed an issue

on page 3 with the d-sub pins. Pin 11 is listed twice (one should be

Pin 10) and Pin 2 is missing (2nd line to the power bus).



I will use the P2 to continue with the software for the wig-wag. I should

have something available later this week to use for testing with the

hardware.


	


   Very good. I'll order boards today when I get back

   to the office.  Been toting barges and lifting bales

   this weekend (moving furniture).

        Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Fri May 04, 2012 9:19 am Post subject: OS Wig-Wag Project

The boards are here and I've stuffed some of the

parts. Thought I'd ordered the IRF6201 hex-fets

but that slipped under the rug. Those are on order

and should be here Monday. May have the development

articles ready to mail then.



How many folks are herding bytes for this board

configuration and need hardware? I need mailing

addresses.



   Bob . . .

gregmchugh

Joined: 03 Apr 2012
Posts: 42

Posted: Fri May 04, 2012 9:50 am Post subject: Re: OS Wig-Wag Project

Bob,



Send one out to me, please...



I will test the current software and if it checks out I will flash some

PIC12F683 chips and send them out to you. If there is anyone else

who is getting one of the initial boards and would like a flashed

micro let me know.



Greg McHugh

4201 N Willoway Estates Ct

Bloomfield Hills, MI 48302

FisherPaulA(at)johndeere.
Guest

Posted: Tue May 08, 2012 12:57 pm Post subject: OS Wig-Wag Project

Bob,

I'd like one of the boards.  I'm not sure if I'll be herding bytes, or they will be herding me, but I'd like to try!  Please let me know what I owe you for it.



Greg - as long as I've got your code, I'll try to flash my own chip... but I'll contact you if I can't get it to work!! 



Thank you!!



Paul A. Fisher

8428 114th Avenue West

Taylor Ridge, Illinois 61284

--

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