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Rich H · Posted: Wed Jun 10, 2009 1:35 am Post subject: The UlLTIMATE Dash Upgrade

As you lot appear to be mostly mental like me, I'd thought I'd share my latest project. If I manage to pull it off I consider it to be the last word in dash upgrades

You can keep your LCD wizzy bollocks, mine is going to be solid 1960's neon display technology coupled with 2009 microprocessor power....

If this intruiges you then please read on.

The Situation:
I get bored without a project and the engine strip/rebuild option doesn't particually inspire me at the moment, still needs doing but it sounds boring. The Porsche is already modified heavily, so why not bling up the dash! I haven't found anything remotely like it apart from a custom speedo on a scooter.
(Worked out recently the only things not modified or changed from original are the short block, the bodyshell, the interior, the front struts and the front wishbones :shock: )

The idea:
I've been playing with 1960's numerical indicator tubes (Numerical Indicator eXperimental 1 = NIX1 = Nixie) and making clocks out of them. They are steam punk-esque display tubes used in loads of old lab equipment and lots of Sci-Fi films made unntil around 1980. So why not make a dislpay for the Porsche....

The plan:
3 digit speedo, 3+0 digit tacho, 3.1 digit trip meter with bargraph neons for the fuel, oil-p, water-t and AFR, neons for all the other warning lights all driven by a microcontroller.

The Snags:
Nixies are glass tubes full of fine wires, they are pretty robust but will they last in a car?
Nixies need 150V DC to run.
I know cock all about Microcontrollers.
I know slightly less about programming in C.

Progress so far:
I have a dozen end view 18mm digit tubes in rectangular-ish tubes that stack together nicely
I have sockets for the above to enable dead-uns to be replaced
I have a LPS2103 microcontroller header board
I haev built an interface including PSU and RS232 interface for it (After a cock up with pin allocations...

)
I managed a bit of C last night - but not alot!

The next steps:
Get the Microcontroller talking to the outside world (Not tried to communicate with it yet)
Get it under control
Learn C
Design display driver/multiplexer circuits (Not as hard as it sounds)

Clock mk1 (Side View Tubes 12mm digits):

Clock Mk2 (End view tubes 18mm digits):

Bargraph Tube (120mm total length):

_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

pocketscience · Posted: Wed Jun 10, 2009 1:49 am Post subject:

As a software engineer with 20-odd years of C experience* my hats off to ya Rich! Sounds like an awesome project - not sure it's one I'd do, but each to their own - and if it keeps you off the streets at night even better!

Keep us updated (and shouldn't this be in the Body & Interior forum?)

G.

* including a published book
_________________
Whoever said you can't buy happiness forgot about Porsche!
81 924 N/A, GTS lights, Saratoga, interior, headers, Integral cam, EFI (sold)
95 993
69 911

Rich H · Posted: Wed Jun 10, 2009 2:02 am Post subject:

My new best friend

Might be back asking for help with code now and then if that's OK... Any recommended books then?

I'm getting a fair bit of help from a chap in Scotland who designs modern car electrical systems who is easily distracted by potty projects!

The actual hardware is quite straight forward, the nixies are just 10 cathodes and a comon anode. PWM the anode for brightness and then BCD IC on a 4 bit word into a 10 bit decimal out will drive one. Multiplex them together and jobs a carrot.

The Bargraphs are just going to be driven by a similar system giving 10 levels in each tube, might be easier to use discrete bargraph driver ICs for them, but ideally all in one.

A reciprical counter code will handle the actual counting bits, I have a frequency counter code I'm going to try and bastardise to sort that then once I have a frequency (Wheel rotation or RPM) I can simply divide by a constant to give MPH or RPM.

Rich
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Very cool!

Will those things stand up to NVH once installed in the dash?
_________________
erstwhile owner of just about every 924 variant ever made

Rich H · Posted: Wed Jun 10, 2009 2:17 am Post subject:

That is an unknown at the moment, I'm planning on doing a trial run with a mobile clock running from the Processor and the PSU designed for the final version, they will need mechanical isolation certainly.

I was planning on building the displays in PVC pipe surrounded with soft neoprene type rubber that will fit neatly in the dash cut outs. The actual numerical displays are relatively small at around an inch high by 3/4 wide, so 4 of them side by side don't take up much space. The Bargraph tubes are much simpler internally so are more mechanically resistant.

The worst that will happen though is internal shorts between the cathodes so 2 numbers light up in place on one, a quick change of the tube will put it right.
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

!tom · Posted: Wed Jun 10, 2009 2:33 am Post subject:

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands

very nice!

Do not underestimate how wonderful tubes can be

if you do it right, they even outperform modern sound systems too..

Never seen these numerical indicators though

very cool.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

Rich H · Posted: Wed Jun 10, 2009 4:29 am Post subject:

I found a couple of old amp tubes in my brothers garage....

Cheers for the offers of help with C I'm going to need it! I'll look the C bible up thanks.

I'll keep you all posted.

Rich
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

pocketscience · Posted: Wed Jun 10, 2009 10:31 am Post subject:

K&R is indeed where you want to start - it's a wonderful reference. You don't want mine, it was specific to developing for handheld computers (eg Palm Pilots etc), and beside it's out of print now.

!tom's hints are great, a few more:

1) single letter variable names are devil-spawn
2) set compiler warning levels as high as possible, then listen and understand
3) don't use #define where you should use const or typedef enums. type-checking is a handy thing the compiler can do for you
4) spend time getting to know the various language constructs, and why you'd choose one over another at any time

Happy to help answer any questions Rich

Cheers,
_________________
Whoever said you can't buy happiness forgot about Porsche!
81 924 N/A, GTS lights, Saratoga, interior, headers, Integral cam, EFI (sold)
95 993
69 911

morghen · Joined: 21 Jan 2005 Posts: 9105 Location: Romania

grrrr cant see the godamn pictures because stupid photobucket is filtred by the network firewall as...entartaining or some...
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Supercharger and EFI kits
https://www.the924.com

!tom · Posted: Wed Jun 10, 2009 3:04 pm Post subject:

pocketscience · Posted: Wed Jun 10, 2009 4:47 pm Post subject:

Rich H · Posted: Wed Jun 10, 2009 5:51 pm Post subject:

I'm planing on using GEDIT and G++ as they are easy to get with Ubuntu.
I did download CodeBlocks IDE but just got confused....

Get the old 'Hello, World' code working, now trying to get the serial link to work. I think it will work I just need to switch to the clockwork laptop with a proper serial port instread of a usbserial adapter.

Once that is up and running then I'll see about a bit of useful code.

I've just been given some idiot-level university notes and "Programming in Ansi C" by Ray Dawson.

Should get me kicked off and a bit easier to follow than most online jobbies.

Cheers gents! I'll be back with questions....

Rich
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

wombat · Posted: Wed Jun 10, 2009 8:40 pm Post subject:

Can I add one devil spawn just because it is giving me the shits at the moment in some c code, pointers causing memory leaks, arrays defined like devil_array[1000000000000000000000000] causing even more memory leaks and the assumption that what you want is always going to be the first thing on the stack so there is no need to add any check code and then it being the 196th thing on the stack and wondering why you have even more memory leaks every time you pop it off. Oh and one more 5, count them 5 different state machines in one piece of code all doing the same thing only 2 of which are any good at what they do, for F*** sake why 5 things doing the same thing????????? Please leave the c code off this board I came here all relaxed and now I am really tense I dont need this. I thought I got away from this a few years ago but I have been looking at some code for my brother in law, now this is where it gets really exciting its gaming code (that was the exciting bit its all down hill from here) for a game I cant name but is for 10 year old girls who like horses, oh and it may be a sequal, any ideas "Friends" lets just say the only way to fix half this code in the time he has is major hacks everywhere great fun. Now please dont talk C any more, but I can help if you need it.
_________________
1977 924 2.0 Auto

Rich H · Posted: Wed Jun 10, 2009 9:43 pm Post subject:

It's good to share! How about if I scatter the C code with pictures of high-voltage antique glowing glassware?

I have the concept of what I want to do, I know some of the structure and I even know some of the details but I lack the knolwedge to write the code.

I am going to concentrate on the structure of what I want first, then start filling in the blanks. I think the hardest bits are going to be the syntax and the actual hardware interface bits, the GPIO stuff.

How do you eat an elephant? One Bite at a time...

First plan - Revs

My Rev counter is buggered as it won't speak to the EDIS.
I need a frequency counter, BCD encoder and a multiplexer
The BCD can be simply done with an IC working on 4 GPIO pins.
The count and multiplex can be done with an event counter and a simple loop (In principal)

Rich
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec