Just a thought i had last night while talking to friend about some electrical, Radio related stuff, has anyone tried to program a PIC CHIP to work as a replacement for the main IC in the Pod.
I know that these are now defunct and not available, and i know there are ways round this should it need replacing, but i am sure that a pic chip would more than do the job and would also be an exact replacement if programed correctly.
Someone may have already tried ?
John
As technology progresses I expect someone will come up with a replacement. Not heard of anyone doing so as yet.
I am just getting in to this side of things, so will have a look at the possibilty of prgramming a pic chip for the POD as a first project, i have a mate of mine who is very good at all this so will look at a bit of design work, there is a lot of free software about, so it shouldn't be to hard a job, that will keep me busy for a bit.
John
Quote from: PLOD11 on 19, February, 2010 - 15:13:09
Just a thought i had last night while talking to friend about some electrical, Radio related stuff, has anyone tried to program a PIC CHIP to work as a replacement for the main IC in the Pod.
Go for it Plod I would love a plug in replacement !!!!!!
as an 'on neded occasion' designer i had also looked into PIC programming for other projects, it takes of time to learn, once you have mastered it then you can get on a and design - but i'm not lever enough :(.
my designs tend to be for small run bespoke projects usually to do with security systems that need 'specials', its just not viable to otherwise to spend the time on learning it.
assuming a member has this skill already, to emulate in a PIC for the C5 Pod you would have to know all the characteristics of inputs and outputs needed to be programed into the PIC before you could proceed with design, so it makes it a tall order imo for whoever has a crack at it.
imo perhaps the way forward is to use the scooter control kits with modern displays, i got mine off Ebay for about £12 with the intention of installing it into my C5 - when ever i get the time its a battery volt indicator and condition indicator meter with alarms for low voltage, also has internal and external external temperature sensor, with a button to switch to choose between them, its about the same size as the pod display, it is LCD and backlit, so far easier to see.
intend to attach the external sensor onto the motor
if the above works out then although the C5 won't be 'original' it will have a viable alternative.
regs
alan
My next question was has anyone got the spec for the ULA chip, i have looked around on the net but not found anything.
As part of my other hobby as a radio Amateur, the pic chip has been used quite a bit in the design of logic boards to run radio repeaters etc, so we have some experience in this, but i know what you saying, it will be a bit of a long shot, but i will speak to those who know and see what we can come up with, the other option was to look at a re design of the POD circuit, keeping the led displays so that it all fits back in to the casing but using some more modern technology.
John
Quote from: PLOD11 on 19, February, 2010 - 18:20:29
My next question was has anyone got the spec for the ULA chip, i have looked around on the net but not found anything.
Sadly this is what prevented some guys I know from making progress.
Some where on the net apparently there is Ferranti archive, it should have details of this chip in that, just got to find it :(
I think the Pod is the weakest link at the moment - with Karl / Dave cracking the gearbox issue - leaving the Pod as the main problem area. From my experience I have had 3 duff Pod's out of 4 all with the ULA being the main issue. If this can be cracked we are looking at keeping them going for a very long time - Personally I think the way to go is the same as Karl has with the gearbox IE a direct replacement even if it is 'new electronics' that can be fitted in the original housing.Keep us informed of developments and good luck !
Forgive my ignorance folks, but is this ULA chip the same as used in other sinclair products?
There's a website called http://www.thesinclairshop.com which stocks replacement Sinclair ULA chips. Here's a technical guide - http://www.retrocomputershack.com/PDF/ZX81-ULA-Doc.pdf
Looks like there are a few available, but like most Sinclair items, they're new old stock, so supplies are limited.
Is this the chip you seek? If not, I'm sorry.
Thanks,
Mike
If it was only that easy !
No the ULA in the C5 is one of hundreds made by ferranti / Plessey and is unique to the C5 and controls the information displayed on the POD display and monitors the condition of the motor and battery.
As said earlier this is the weak link in the C5, and if we can't program a pic chip then we will be looking at a replacement board, with some new technology built on to a similar size board to fit into the existing POD.
So watch this space, i will be speaking to a man next week who has the ability to help with this, buts its convincing him that it is worth doing. :-\
Quote from: PLOD11 on 20, February, 2010 - 13:58:32
..... buts its convincing him that it is worth doing. :-\
You've hit the nail on the head there mate.
I've found to my cost on previous occassions that the market for C5 stuff is really quite small !
You're right to resist the temptation to get too carried away. :)
The ULA in the pod was custom made for the job & thats the problem 1. As far as I am aware there are no papers on this chip & thats problem 2.
As far as originality goes we need replacement pods. But as far as usability or 24v kits go its not an issue.
Can we get a donor ULA to be decapped so we can try and decode it? I have a (few) people in mind who would be up for the challenge, and of course once its documented there are more than a handful of people who would be up to the jobn of emulating / simulating it on a pic.
I of course at the moment don't have any c5 hardware let alone a pod..
A year ago a C5 with "Circuit diagrams and a prototype pic chip replacement for the somewhat dodgy ferranti ULA" was offered for sale (unsuccessfull?) at a New-Zealand auction web site:
http://www.trademe.co.nz/nz/auction-206515627.htm
So what happened to that circuit diagrams and the prototype?
Greetings from Germany,
Henning
That message from NZ would be Chris, the creator of c5alive - never met him myself but have chatted via email.
There are some circuit diagrams that Chris composed for the c5alive forum ,they are still available on the download section of the main C5alive website.
No idea what happened to the replacement prototype chip :-\
My mate and my self have looked at this and as said before the amount of work needed to develope it with out any info on the original chip it was not worth the effort and cost considering how few people it would want it.
But if anyone has the info on the protype chip we would be interested.
John
Quote from: PLOD11 on 25, April, 2010 - 16:58:33
My mate and my self have looked at this and as said before the amount of work needed to develope it with out any info on the original chip it was not worth the effort and cost considering how few people it would want it.
But if anyone has the info on the protype chip we would be interested.
John
Friend of mine is still convinced that a slot in replacement is workable and wouldnt require vast ammounts of work. We are only talking about replicating a *very small* ammount of circuitry here, and the goal is to replicate the results, rather than a 1:1 copy of the ic.
With c5martin stepping back from pod and control box repairs, we will need to find a solution fairly soon.
I think new pods were £160 from Adam ?
Is there any chance whatsoever of me getting a donor ULA to put towards the development of the replacement?
Obviously if i had my own, I'd give that, but at the moment I'm totally C5-less :(
Quote from: MikeDX on 25, April, 2010 - 21:51:05
Is there any chance whatsoever of me getting a donor ULA to put towards the development of the replacement?
Obviously if i had my own, I'd give that, but at the moment I'm totally C5-less :(
Would this mean sacrificing a working pod, or would it involve no damage/dismantling at all ?
Quote from: BooBoo on 25, April, 2010 - 22:10:55
Quote from: MikeDX on 25, April, 2010 - 21:51:05
Is there any chance whatsoever of me getting a donor ULA to put towards the development of the replacement?
Obviously if i had my own, I'd give that, but at the moment I'm totally C5-less :(
Would this mean sacrificing a working pod, or would it involve no damage/dismantling at all ?
No, this is purely so that it can be logic probed and analysed :) A safe return in one piece is the preferable option!
The only thing that would be sacrificed if anything would be the actual ULA itself, and that's only if it were to be de-capped (not likely).
I am defiantly willing to try to make a PIC replacement for the ULA. Unfortunately I'm unable to do so at the moment as revision is about to commence and I have *loads* of exams in less than a month. (Second year Uni, Electronic & Electrical Engineering) But, give me about a month and 2 weeks or so, and I'll have finished and be able to devote some time to this. Honestly I don't see it being too difficult. All it needs to do is monitor the battery level, battery usage and temperature, with a piezo alert output, the two multiplexed displays and obviously a signal back to the control box to give it the 'ok' to run. Might even be possible to do it in logic, i.e. no programming required...
It may be easier to make a new board than use the existing one, so I'll look into doing either or both.
I do think, however, that any work done on this should be released publicly (i.e. code & layouts). We don't want someone doing loads of work on this and then disappearing, taking everything with them, requiring someone else to do it all again (which by the looks of it has already happened once).
May I encouage you to GO FOR IT dude !!!!
What radiomarty said !! ;D
If you achieve this you will be elevated to a god-like legendary status mate :-* , bit like C5Martin , Adam Harper and ElectricDave ;)
Hi forum, for what its worth I have considered offering a pod and box repair service for C5's after the summer... Would there be interest or is somebody already doing that successfully?
it would be hi-stoic work to achieve a replica replacement, but as a designer i wonder when you can buy these as example -:
http://cgi.ebay.co.uk/12v-battery-monitor-voltage-level-charge-state-meter-/150440704794?cmd=ViewItem&pt=UK_AudioElectronicsVideo_Video_TelevisionSetTopBoxes&hash=item2306f6fb1a
and so cheaply, is the effort really going to be worthwhile for the amount of sales? :-\
the C5 can be run without the pod, plenty of the battery volt monitors out there with alarms for about £12 designed for cars, the one i have has LCD display and an external temp sensor, so could be used to monitor the motors temp
imo possibly the best way forward balancing ease v originality is to use the existing pod but transplant the electronics from a modern bar graph version to operate the original display.
but even then, i find my (so far working :) ) pod hard to see in the sunlight.
regs
Alan
I think with the fact that C5Martin is moving on to kit cars that the service ie pod and control box repairs would be a very useful thing to have - check with Boo Boo on the current situation.
I think this is definitely along the right lines - a simple,ready made "off the shelf" replacement item that is easily obtained has to be the way forward.
Although he might still be doing occassional repairs when time allows, C5martin has pretty much moved on now so we need to find an alternative.
I am exploring a couple of options .....
The very fact that they offer a custom programming option for those modules tells you that it's probably just a PIC running a little program. As I said before, I don't expect any replacement pod to be too complicated, I'd just like to be able to produce something complete, something that you can grab, swap for your ULA (or pod board) and go.
Quote from: aladds on 14, May, 2010 - 16:53:37
..... I don't expect any replacement pod to be too complicated, I'd just like to be able to produce something complete, something that you can grab, swap for your ULA (or pod board) and go.
Sounds just the job ;)
Right. I've finished Uni for the year, and although I do have a summer job I've got some time to actually put quite a bit of effort into this.
I've been looking at circuit diagrams, methods of checking battery level and current metering, and I think I've realised a few things.
Firstly, replacing the main ULA with a PIC is completely possible and shouldn't be too hard. I _might_ have a working prototype by the end of the week.
Secondly, it may be easier to make a whole new POD, Sinclair didn't use any Analogue to Digital Converters, so some of the inputs to the ULA aren't in ADC friendly form, I'll have to check that though. Hopefully I should be getting an old oscilloscope from our electronics lab today (if the lab techs are nice!) so I'll be able to properly analyse exactly what's going on in checking current & voltage. (Voltage is easy, current should be but the inputs to the ULA regarding current are confusing me)
The only difficulties I can see are, as I've said, getting the signals from the control box into a friendly form for analysis. Once that's done everything should be easy. Controlling the LEDs and buzzer, for example, is really easy!
Also, would anyone be interested in some sort of data logging? There's not that much information available, but I could get it to record current & voltage over time, for download to computer for analysis. Might be a little more work but shouldn't be too hard to do... That wouldn't be in the first version though!
Good stuff - Hope you can crack it !
Well our lab wouldn't give me an old oscilloscope (something about health and safety...) but I'll see what I can do without one. If anyone has one in or around Cambridge I'd be interested :-) (I might be able to make do with a PC sound card...)
Good luck with this mate, fingers crossed you get it sorted 8)
Well, currently having a little trouble working out what's up with my control box. It's good enough to drive but I think the 5v regulator is buggered up. I'm trying to work out exactly what's up and if i can swap a bit 7805 in for it. I've got one of those lying around so if I can that would be the best solution right now. My Pod is fully working as far as I can tell from running it on my desk, and I've started making a PIC adaptor for it. This will take a little longer than expected due to this 5v problem, but I recon I'll get something going soon enough :-)
I have replaced the 5 volt regulator for a 7805, and had no problems ;D
I have used this regulator on at least 3 repairs and as plod says no problems
Yep, just done it. Lights are now nice and bright but current sensing doesn't seem to work... Took it up the road later and it's still no good so I suspect the LM358 opamp... it looks ok, but someone might have previously released the magic smoke... I'll pop and get one tomorrow!
I've got to be careful what I do though, as I'm currently using it to commute to work, so I'd better not break anything!
As soon as current sensing works with the ULA I'll be able to start working out how I'm going to detect current with a PIC. I suspect it should be easy enough. Checking the battery level should be a breeze. My little test board is coming along nicely, should be able to get some deliverable results soon.
Well done, keep up the good work ... ;D
If you need a hand with anything let us know .... ;)
PLOD
All good stuff mate - hoping you can crack it ! :) :) :)
I've swapped a new LM358 in, but current sensing still isn't working, are there any other common issues the control box can have with current sensing? The wiring to the current shunt looks ok... Perhaps my ULA is shot (not necessarily a problem, but might make it a little harder to work out if my PIC is working properly!)
Update.
Ok, so this project has had a little bit of a setback due to unforeseen (unrelated) circumstances which have consumed much of my time. That's mostly sorted out now, although there are still a few things I need to do. Anyway, the important thing is I can now devote a little more time to making a new ULA. With luck I can show something off soon :-)
No worries mate , just pleased you're having a go at sorting it :).
How long it takes isn't really an issue ;)
I still need to fix my current sensing, it doesn't report anything at the moment, but I've made a little more progress. I've got a preliminary circuit diagram, some skeleton software code and a half-built hardware prototype. It's hard to find the time to work on this, but I should be able to finish off the hardware and start implementing and testing software in the next few weeks.
At that stage I'll only be able to display values, buzz the buzzer, read the voltage, report that everything is ok (or not!) to the control box and *I think* read the inner temperature probe. As my current meter doesn't work at the moment I won't be able to test that to see either how it works or try to guess at re-implementing it. Obviously if I get that working then I'll have a much better idea of how to set that up!
I'll keep everyone posted as to my progress, of course, so watch this space!
Good stuff - great to hear the progress to date - keep at it. :)