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1987 Renault GTA :: Gone to a new home


PhilA

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Jesus Christ man, your tenacity is truly astonishing.

The electrickery - breathtaking. But when you've ironed out all the bugs, you know it's gonna be SO worth your efforts.

 

I fail at electronics...

INCORRECT.

Keep up the good work.

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Jesus Christ man, your tenacity is truly astonishing.

The electrickery - breathtaking. But when you've ironed out all the bugs, you know it's gonna be SO worth your efforts.

 

I fail at electronics...

INCORRECT.

Keep up the good work.

 

 

I'm going to try. Once I'm done, in theory, it should be quite a nice car to pootle about in. The wife is also going to have to get used to the idea of towing me places.

 

Keeping at it, just progress is slow because the car's not stored where I'm living any more.

 

--Phil

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Here's how the Alliance compared to the competition, in the eyes on AMC-Jeep-Renault's publicity department. No bias here! :roll:

 

 

Note: by 1987, the Encore name on the hatch models had been dropped. The hatch (R11) was now known as the Alliance Hatchback.

 

 

Hee, thanks for those. It's amusing to watch- the GTA is the best handling vehicle sold in '87 in the USA. Watch the first video and see when the guy takes a right and goes up the hill... the suspension goes GLOOP WOBBLE. Mine is soft like that too- typical smooth Renault ride. It feels positive to drive, but I've been driving a 3 ton pickup truck around, which has considerably more inertia. It's not got the comic 70's boat-like handling that they are pointing out in the films- a lot of large family sedans from the same sort of era would be howling their tires around those curves and lurching over those crests, even at that speed. Despite that, it's sold as a "sports" model.

 

Mind you, some of the roads here are teeth-shakingly bad. You need something to soak up the bumps.

 

It's got a fair bit of get-up-and-go, even with 96 horses under the bonnet. Yup, 96hp from 2.0 litres. Why? It's actually not emissions junk, it was detuned for a purpose. They gave this engine a longer stroke crank for more torque. 116lbft at (I think) 2800 rpm. It feels like it too. Torque steer in first and second. Not something you can normally say about a non-turbo Renault 9...

 

Looking forward to driving it. As for when that's going to happen... not sure yet. Watch this space.

 

--Phil

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I love how they rip into the Chevrolet Chevette. Talk about an easy target! The Chevette was crap in 1977. By 1987, it was a total embarrassment!

 

 

There's actually a Chevette in Plymouth guise in this area that I know of. Maybe I'll race it. Last time I saw it, it was sounding particularly unhealthy and trailing a fair bit of smoke. Factory fresh.

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I love how they rip into the Chevrolet Chevette. Talk about an easy target! The Chevette was crap in 1977. By 1987, it was a total embarrassment!

 

 

There's actually a Chevette in Plymouth guise in this area that I know of. Maybe I'll race it. Last time I saw it, it was sounding particularly unhealthy and trailing a fair bit of smoke. Factory fresh.

 

 

 

Plymouth? I think you mean Pontiac. The Pontiac T-1000 was a badge engineered Chevette.

 

pontiac-t-1000-08.jpg

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I love how they rip into the Chevrolet Chevette. Talk about an easy target! The Chevette was crap in 1977. By 1987, it was a total embarrassment!

 

 

There's actually a Chevette in Plymouth guise in this area that I know of. Maybe I'll race it. Last time I saw it, it was sounding particularly unhealthy and trailing a fair bit of smoke. Factory fresh.

 

 

 

Plymouth? I think you mean Pontiac. The Pontiac T-1000 was a badge engineered Chevette.

 

pontiac-t-1000-08.jpg

 

Oop. you're right. :D

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Well, well, well.

 

Been a while since I posted anything productive. Had a fairly large stint of overtime at the weekend due to the inclement weather. This is normally a good thing, as it leads to the possibility of buying spares for the car.

 

Was all set to use this to buy me the brakes bits I need. Today we get a letter in the mailbox from the postmaster stating our postal mail is on hold until we repair our mailbox- which is 6" too far away from the street and 8" too low. Reason for the complaint? The more recent SPEED HUMP sign that was planted in front of the mailbox now blocks access to it from the van.

 

The original mailbox pole has rusted through, so it's been wedged in the ground by someone before we moved here. It's been like that for years, but they choose now to whine about it.

 

Joy. New pole with an arm on it? There goes my brakes.

 

--Phil

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Found a few dollars hanging about so went bought an oil filter for the wife's daily, some NPN transistors at Radio shack and a little development board with space to build electronic circuits on for the Arduino.

 

IMAG0667.jpg

 

It's cheating, but it comes with everything drilled right, so all I have to do is build the thing up on the breadboard, make it work, then hook up to the outside world using this board as the go-between- I can stack stuff on top too which is pretty neat, was looking at their microprocessor controlled LCD screen- no pfaff with timing and such for LCD gubbins, just send it serial data and BAZAM it comes up on the screen. Win.

 

--Phil

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The Internet ate my photographs. I spent some time today at work doing some calculation (woo doing it properly) to determine what parts of the circuit should have what electronic components and in what order.

 

Built it tonight on the breadboard. Net result yellow led comes on when I touch a wire to ground on the circuit.

 

That is meant to happen. Got a few checks to make on it but looking promising. If it works it goes onto the prototype board pictured above, and becomes the first production model.

 

Wish me luck.

 

-Phil

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IMAG0669.jpg

 

Sat down with pen and paper and calculator and datasheets and worked out what goes where.

 

Built it up on the breadboard to test.

 

IMAG0670.jpg

 

Basically what I've done here is to isolate the positive voltage rail of the car and the data rail of the Arduino board- the car is anywhere from 8v to 15v depending on running state and battery, and the Arduino is expecting 5V exactly on the data in line, regulated down from 7-12v input supply.

 

The input voltage from the car that is driving the data has a tendency to float- if the Arduino is connected to the car well this isn't an issue but the line can get awfully spiky with noise picked up from the bit long wire going from it to the engine bay. Acts like a radio antenna, in effect. This can cause damage to the input circuitry, and also causes data errors.

 

So, the voltage coming from the car is regulated 12V by the big black bit on the left- it's going to fall below this, but it won't go above- and this powers the "car" side of the circuit (for those of you who need to know, it's open-collector output, so it's being driven high by the voltage divider). The car causes a light to blink inside one of the chips, which translates to a transistor inside, and switches it on or off respectively.

The transistor side of this chip isn't connected electrically to the other side- only by light. So, those spikes can't get through it, worst they can do is burn up the little light inside... which is fairly expensive, so a plain-jane transistor sits before it (all of about ten cents worth) to protect that a little from going pop.

 

The signal is "upside-down" coming out the other side of the isolator, so another transistor flips it the right way up for the Arduino to read it.

 

That's the premise- need to poke about a bit with my oscilloscope and multimeter but my calculations were correct. Nothing went up in smoke when I powered it up :)

 

--Phil

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I have absolutly no idea what any of that means. :lol:

 

Plumbing!

 

Part of the issue is that the car's a high-pressure line, the Arduino computer board (the little blue bit, henceforth referred to as Arduino) is a low-pressure system- if I connect the high pressure system, it'll bust it wide open.

 

The car can be thought of like a toilet. The car controls the flush handle. The transistor on the left is a big valve that is operated off the ballcock- when the cistern is full because the computer isn't holding the flush, it doesn't fill up. When the cistern is empty however, the valve opens. In the pipe from this valve is a small generator on a waterwheel that lights a light up when the toilet is being filled.

 

That light shines on an a smaller toilet's flush valve, which has a sensor on it. When the light shines, the smaller toilet flushes. This means that there's no high-pressure stuff working the smaller toilet.

 

Unfortunately now, when the car flushes the big toilet, the smaller toilet fills up- this is upside down from what we want, so we add another ballcock valve with a generator on a waterwheel- when the small one fills up, the waterwheel stops- back where we started, mimicking the flush valve. The car presses the flush and the output light on the far end of the pipework lights up. WINAR!

 

--Phil ;)

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My wife made me get rid of my oldTektronix 564 storage Oscilloscope as it took up too much space in our British house, I had to borrow one from work if I needed one at home. I Don't recognize the function generator is it a HP?

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My wife made me get rid of my oldTektronix 564 storage Oscilloscope as it took up too much space in our British house, I had to borrow one from work if I needed one at home. I Don't recognize the function generator is it a HP?

 

It's a Wavetek device, I forget the model number. It's addressable serially and you can chain them together to create.. lots of function generators.

 

It's wildly off calibration and horribly unreliable. Perfect!

 

The frequency counter is an HP though, at the bottom. It smells of old.

 

I miss my oscilloscope I have in the UK- Tektronix 585a which is "luggable" at best. We have an old Tek storage scope here at work that hasn't been fired up in a few decades. With new capacitors it'll probably run again.

 

--Phil

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IMAG0672.jpg

 

Daaaa- DUM.

 

Daaaaa- DUM.

 

Da-DUM-Da-DUM-Da-DUM-DADADADADADUMMMMMMM

 

Yeah, I have sharks in my oscilloscope.

Ultimately this is a bad thing, as that is the output trace from the circuit I built. It has a nice clean square wave put in from my waveform generator at approximately the same speed as the car's computer spits out.

It should be a nice square wave too.

 

IMAG0674.jpg

 

Much fettling and head-scratching later and I sussed it- needed to bias the base of the second transistor because the capacitance between it and the optoisolator was too great, making the malformed waveform above.

 

Press the ON button, making a noise like a BBC Microcomputer keyboard, and...

 

IMAG0673.jpg

 

Ta-DAA! Much better.

 

Next up, seeing if it'll chat with the car or not.

 

--Phil

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What value resistor did you use to bias the base of the second transistor with? 2k2 ?

 

Yep, 2k2 to ground. The Arduino has a 2k2 pulling the circuit up from 5V, and with the 0.9V drop across the transistor the circuit p-p is 4.1V so it's way happy being driven there, its threshold is about 1.8V, suggested anywhere from 2.5 up to 5.0 as positive, if my memory serves for a positive logic 1.

 

--Phil

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Well, yesterday was a definite success.

 

Set out to change the oil on the wife's daily. It was kinda breezy, but set the big drum fan on it anyway to cool things down a bit more rapidly after the drive over.

impala_fan.jpg

 

Whilst that was cooling off, the car assumed the position again:

car_set_up_again.jpg

 

Got the new circuitry hooked up:

computer_and_interface.jpg

 

Was it all in vain? Indeed no! Those numbers on the right (and my crib sheet on the left) show that it's reading sensible stuff from the car and spitting it out in a sensible fashion on the screen.

 

Win.

 

good_datajpg.jpg

 

There's a few things on there that I'm getting a bit of an idea about- helpfully there's a byte there that gives me my air:fuel ratio in exact terms. Nice of it to calculate that for me.

Can't get much more off it without actually driving it under load but that's a definite things, so I'm now building it up on the little prototyping board I bought that plugs directly into the Arduino.

 

If I can get that to work then that'll be a step in the right direction.

 

Wife has some nice hand-crafted pottery as of this weekend too. There go my brakes again.

 

--Phil

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I started with a small blue board full of holes

empty_prototype_board.jpg

 

A breadboard of working circuit which is messy

circuit_on_breadboard.jpg

 

Which got translated onto the board full of holes which is tidier

circuit_lain_out.jpg

Still have to trim all the legs off the back and solder it in but that's pretty compact.

I've made a few adjustments here and there since I pictured it but that does leave space for other things to be put on the board- if it is to drive stuff like panel meters then it'll need trimpots to be attached to the pins closest to the empty space.

 

Progress is being made again. SWMBO even said I can buy my brakes.

 

For now, I'll just put this thing together, which is a bit smaller than a packet of cigs.

 

piggybacked.jpg

 

:D

 

--Phil

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Good luck.

The electronics are way over my head, but I'm really looking forward to seeing this car sorted. Great work.

I've not really delved much into what I'm doing- looks more complex than it really is.

 

Your thread makes my brain hurt... :wink:

Just think how I felt the other evening trying to work this out after dinner and a couple glasses of wine ;)

 

--Phil

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Had a bit of free time tonight so I sat down at the desk here and scratched my head a bit and tried to remember just what the hell I'd been thinking wiring this thing up.

 

Got all busy with the soldering iron, and voila, thirty minutes later we have this:

back_soldered.jpg

 

Which up front looks like this, annotated helpfully in Paint:

description_board.jpg

 

The bits in the green square are the regulated power supply. The car is powering this, and the little board is expecting no more than 12V input. This bleeds off any extra volts that may try to find their way in.

The purple bit is the signal coming in from the car. It goes into the black blob on the right.

 

the blue line is turned on and off by the purple bit in the black blob- important to note that although they get close, they never touch- the blue bit is all nice and happy and computer-voltages, the purple one is all the voltages that make the car happy. They aren't exactly compatible, so they're separated there.

 

Net result? Powered up and connected:

powered_up.jpg

 

If it wasn't working this much, then the lights wouldn't both be on. Result.

 

Need to order some connector plugs, and I'll be ready to roll.

 

--Phil

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As Trigger says, this thread hurts my head too - but I am enjoying watching this collection of bits and pieces becoming an ECU.

 

Love your car - my Dad had a Renault 9 (basically a 4 door version of yours) which he had for 14 years until a drunk driver rammed it outside my sisters place one night. Dad scrapped it, in fact I think he paid for someone to take it away!.

 

Wish I'd kept it as it would have been a great donor for other renaults, probably would have a made a few quid....

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