[rally_prep] Rally Build : Custom Dashboard / Wiring

[brumster 135 1 Cars]

I went with qualplast in the end; it's with them today and hopfully ready by Thursday/Friday. Not the cheapest at £90 (considering it's a pretty small moulding by conventional dashboard standards), but they're local so it's less hassle and the quality of their work is in no doubt... well, I say that, we'll find out Friday, but I'm not too worried ... watch this space...

[brumster 135 1 Cars]

And the final result....

 

 

I am grinning from ear to ear, really please with the result and the quality of the flocking is excellent. They apparently do all the Prodrive and M-Sport flocking, so if it's good enough for Dave and Malcolm then it's good enough for me ;-)

 

 

 

Will start inserting switchgear, instruments, heater vents and so forth tomorrow and building up a wiring harness that's part of the dash. This will then join into the main loom via multiplugs so it can be easily removed later on.

[brumster 135 1 Cars]

Switchgear now in place, and half the wiring behind too. Just need to put the hazard switch in somewhere...

 

 

From left to right we have :-

Motec CAN bus connector

A fuse board for small ancillary circuits not powered off the PDM (brake lights, side lights, stuff like that - room for expansion)

Trip computer

6 momentary switches and warning lights for inner spots, outer spots, cooling fan override, power steering pump, rear fog light and demister fan

Two small red buttons are function buttons for the SPA rev counter and oil pressure/temperature gauge

 

In the binacle part :-

Two Panelpilot LCD displays for water temperature, fuel pressure and fuel level

SPA rev counter

SPA combo oil temperature and pressure gauge (digital)

A racetech voltmeter

 

And some standard warning lights for the usual - indicators, main beams, alternator charge warning, sidelights, hazards.

[Iain-gti 6]

Looks really good well done!

[brumster 135 1 Cars]

Looks really good well done!

 

Thanks, chap it's been a bit of a labour of love the last 8 weeks - all the more satisying when you get to the end result. Even the missus walked into the garage and said how great it looked and, believe me, coming from her that's something special

[brumster 135 1 Cars]

Some other jobs have taken up the last days (gearbox mounts, etc) but today I managed to get back to finished the dashboard related wiring.

 

I'm putting a loom on the underside of the dash, connecting into the wiring loom and PDM via multiconnectors so that the dash can be easily removed if need be, with only the need to break a few connector plugs and lift it out.

 

It looks chaos but it's actually not too bad. There's a temporary bit of wiring on there in the middle - you'll notice a fuel tank sender unit...

 

 

..and a homemade PCB...

 

The PCB was designed in CADSoft Eagle by myself, printed up onto toner transfer paper, and etched onto the board DIY-style. It just makes a nice, more formal version of the breadboarded example you can see in the first few posts. It's basically a 5v regulated power supply incorporating 3 voltage dividers set up for the water temperature sender, fuel pressure sender and the fuel level sender. To prove it all works before I seal and wire it all up, I rigged a power supply up to it all and bench tested it.

 

Whaddya know - it works....!

 

Slid the sender up and down to verify, and sure enough the gauge operates in line.

 

For reference, 13ohms at top (full), 270 ohms at bottom (empty). I used a 57 ohm resistance in a divider setup to feed the gauge, which equates to 4.07v at full or 0.87v at empty. Just set up the PanelPilots with those voltage figures, and bobs you're uncle...

 

Chuffed for the second time in as many weeks this project is going too smoothly for my liking!

[rallyeash 155]

looks fantastic, well done.

 

group buy? lol

[brumster 135 1 Cars]

Group buy, chuckle I can get a run of boards done for about £6-7 each provided I order enough (ie. 18)... the Panel Pilots are about £60 each last time I looked, and then there's probably a few quids worth of components on the board itself. So I guess it's about £70 assuming people would be happy soldering their own bits in place - it's certainly not practical for me to etch that many, took a fecking age doubt there'd be that many takers though, just for a fancy fuel gauge

[brumster 135 1 Cars]

Busy couple of days and not much to show for it.

 

Spent the day grafting on all the connectors - those to the dashboard and also the connectors into the PDM. These are AMP Superseal connectors and they are, quite frankly, a pig to work with. The gauge of the wire that will fit into the connector blocks, once crimped, is pretty small - the 20A outputs are achieved by doubling up a pair of connections, since you can't get a thick gauge wire into there. Very fiddly - a right ballache. If they don't crimp perfectly cleanly they tug or catch on the block as you're trying to push them home - not too bad with a proper Superseal crimp tool, but even then some of them needed a bit of 'fine tune crimping' with a pair of pliers :S

 

Made up a supporting frame for the dashboard with some square-section steel and the welder...

 

Also last minute figured I'd glue a buzzer onto the underside of the dashboard because I wouldn't have the click of a relay any more to remind me the flashers are going...!

 

Few little things like wiring up the common indicator warning lamp with a pair of diodes to the indicator circuits, but otherwise it was just very monotonous wiring, with checking along the way - including wiring the RH column stalk for the wipers, which will now work slightly differently. 1st down will do nothing, 2nd down will be intermittent and 3rd down will be wipe, with the pull action doing the usual wash/wipe. But the stalk will switch the wires to earth, as the PDM prefers to be pulled low rather than be fed with a live.

 

Also figured out the pin-outs of the hazard switch so I can use it to drive the PDM low on press, but also continue to be illuminated with the switchgear, and flash along with the hazards when in operation.

 

All silly little things really, but take some time....

 

More to come still... next weekend!

[brumster 135 1 Cars]

Dash now in-situ and most of the subloom from it done; need to finish some grafting into the main loom tomorrow. I've made a note of all the pin-outs from the standard 205 column stalks; they all now switch to earth which saves on wires and is a lot easier.

 

 

Came to push the connectors into the PDM and I don't know what the f*** is going on with them, but s*it me they wouldn't push home. Checked them over and over again, but all the pins are good, everything fine, just seems to need a monumental shove to get them home - had to squeeze them in with some clamps :-o

 

 

Hopefully get to the point where I can test the PDM tomorrow...

[edbar 6]

Looks sweet Dan, going to have to come up again to have a look! Well done!

[brumster 135 1 Cars]

I'll put the kettle on this time

[edbar 6]

Its a deal!

[brumster 135 1 Cars]

Good news today; got the bulk of the PDM wiring completed and managed to test it out and verify it's all working. I was a little bit amazed to find it worked first time; I should have more faith in my wiring abilities, but I guess it's the pay-off of being slow and meticulous with things... in summary, one minor kludge, I've wired a warning light wrong for the switch above it and need to swap a couple of spade connectors around, otherwise that's it :-o...

 

Easier to explain with a video so I did a quick little grab with my phone; unfortunately the sound goes out-of-sync but I'm sure it helps you get the idea....

 

http://www.youtube.com/watch?v=WFmFGt-6aVQ

 

Amazingly flexible. Here we can see the PDM switching the hazards. No relays or fuses involved anywhere; when the PDM detects a low signal on the hazard input wire, it starts cycling both the RH and LH signal channels at regular intervals. The buzzer may appear loud but when you've got it running and rattling around on stage, it'll be quite useful

 

It's all downhill from here... I'll now take some time to do some formal wiring diagrams/PDM notes and get them up on here in due course.

[Iain-gti 6]

I was looking at those screens pretty good price, they easy enough to set up and wire in??

[brumster 135 1 Cars]

I was looking at those screens pretty good price, they easy enough to set up and wire in??

 

Yep, they have a mini USB connector on the back for a PC connection, and essentially 4 wires... +12v, GND and two inputs for the senders.

 

I've just ordered a batch of fabricated PCBs if anyone is interested... nothing fancy, just a 5v power supply with room for 4 voltage dividers (ie. four pairs of fuses of your own denomination) so that you can run 4 senders through the one board, so it should support 2 displays. With a 1A regulator you can power two displays off it if you want (although to be honest they'll run straight off 12v so not necessary).

 

When they come in I'll see what they're like and put some pics up. Should be a bit better than my home-etched effort

 

Setting them up is easy peasy... maybe another video coming up, I suspect!

[brumster 135 1 Cars]

So not much updated on this because, in reality, I've been doing lots of those non-electric jobs. The car is starting to look like a car again; suspension back on, calipers serviced, wheels back on, doors fitted, glass back in, roof vent, lots of pipework finished off, footwell liners, gear linkage, seat mounts, and so on.

 

Engine back in....

 

Doors (need fine adjustment still)....

 

Just putting the doors on has worked wonders for my enthusiasm; it's starting to look like a car again. And the clean rallye-look arches and no side trim really seems to set it off in white.

 

 

One thing that IS related to the electrical side of things that I can report on. Remember that custom PCB I made a while back? Well, since I was comfortable knowing it worked, I had a batch of 10 proper boards made up...

 

 

Considering they're just simple 5v regulated power supplies with four voltage dividers in them, there's not really a lot there but it looks so much more professional on proper boards. Thanks to www.pcbtrain.co.uk for that... it was my first foray into getting boards made up, so I was a little nervous ordering £100 worth of boards, but they came out spot on at the first attempt.

 

More updates as they come in... still some gearbox bracket fabrication to do and other stuff before I'll get to finish off the engine bay wiring and show it all working 'properly'....

[brumster 135 1 Cars]

Last of the niggly jobs out of the way this weekend - fabricated this bracket for the Grp-A style gearbox mount.

 

 

Should be plain sailing now, mostly just bolting things back on in the engine bay and plumbing up stuff....

[EdCherry 34 1 Cars]

Those wishbone bushes?

 

Looks good!

[brumster 135 1 Cars]

Well spotted that man !

[edbar 6]

Noice,toight ! Always fancied doing that sort of mount myself, need rid of power plant woes first though

[brumster 135 1 Cars]

It's a bit of a rigmorole but given the regularity of engine/box coming out it makes sense in this car I guess - makes swapping the engine/box a lot easier, and of course it'll be stronger and 'toighter'

 

Basically the chassis leg is plated with 3mm steel on both sides (V'd together underneath), then I've put 3 (or you could do 4) turned steel bosses through the leg. These are just a bit longer than the thickness of the leg so they're welded around each end into the leg, and then you bolt up through them and the bracket on the inner face. The two top-bolts on the original gearbox/battery bracket are re-used also, to hold the top of the bracket tight to the leg and I guess they'd combat any twisting force down on the bracket by the weight of the box.

 

The bracket part on the box is not made by myself; AB do those as a pattern and like you pointed out, they use wishbone bushes and then a 10mm bolt through them and into the bracket.

 

I've done so much practising over the years that I'm now happy enough that my welding is to as good a standard as is needed for this bracket, and welding 3mm steel off the car is much easier than thin panels and important stuff like safety cages (which I wouldn't attempt myself!). So if you're happy with a bit of welding, it's a worthwhile mod if you want some additional strength and/or ease of access for engine in/out operations.

[parry 23 1 Cars]

great build! Withe the fuel sender did you simply disconnect the 12v feed and use your own 5v feed for the sender unit?

[brumster 135 1 Cars]

Yes, that's right. My board supplies the 5v and the return comes into a potential divider that feeds the display. If anyone wants any boards, by the way, I can send some at cost. They worked out at £15 each and they have 4 dividers in them so you could potentially run 4 senders units off them. Granted there's not much to them other than a 5v supply and 4 dividers, but they're at least all made up properly and nicely rather than you having to self-etch one. I only had a batch of 10 made up, if I'd have committed to more they could have been cheaper but I didn't fancy putting myself up for too many of the things !!

[brumster 135 1 Cars]

A little more on the PDM and how it's configured up, now it's working....

 

The software allows the following configuration aspects. One of your first jobs is to set up all of your input pins, of which the PDM has 16. You name their channel for ease of reference and set when they're considered active (high - ie. 12v gets fed into the pin, or low ie. the pin is shorted to earth). The PDM is really set up for active-low, and any active-high channels will need pull-up resistors externally, so most of these are active-low. Purely from a wiring perspective, it means less wire in the car and it's safer too.

 

 

An example input pin configuration, here for the wiper motor park circuit... this pin earths out when the motor is in park, and so is used to tell the PDM when to stop power to the motor coil winding. The voltages have been played around with here for necessity as inductance makes it hard to pick up the park state with the original voltage settings.

 

 

The PDM can also use CAN for inputs, to save on wiring and potentially have access to a lot more than just 16 channels on input. However MoTeC's PDM can only look into a 4-address range of CAN frames, which is worth noting as it caused me a problem in that 2 of the CAN messages I was interested in out of my ECU are more than 4 frames apart, so I can look at one or t'other, but not both.

 

 

I was interested in wheel (car) speed, to alter the intermittent wipe speed according to it, and also water temperature so I could turn the fan on and off automatically. In the end, I plumped for the latter, as it's more essential than the former. Bit of a shame I can't do both, but I have plans afoot to fix that longer-term with a little MCU project to implement a "CAN bridge" that will re-publish certain messages it receives back out on a different ID.

 

Here you can see the water temperature configured for frame 0x307, and it's the first 8 bits in that frame so no offset needed...

 

 

Next thing you'd set up are the conditions. These allow you to set up logic operations and create additional channels. These channels can be derived from multiple sources, for example, allowing you to combine various inputs into a logical output (the channel). You can then use this channel to drive operations on output pins. The conditions allow for some quite complex logic if you need.

 

 

I've got some channels which basically toggle on the button input - this is just because I've used momentary push buttons rather than on/off's.

I've then got some pump prime channels which basically just prime the fuel pumps when the engine isn't running and the ignition is turned on.

Finally there's some wiper-based channels, one to effect an intermittent wipe and two others to drive some logic for wash-wipe (phase 1 basically keeps the wash/wipe programme running once the stalk if flicked - this means in the heat of a rally stage I only need to flick the wash/wipe to activate 6 seconds of wash/wipe, rather than hold the stalk. The 2nd phase handles a pause of 5 seconds from the end of phase 1, before it kicks off a single clear-up wipe of the screen to remove any streaks).

 

A closer look at one of the conditions, showing how the logic is built up...

 

You have lots of nester and/or's with various operations you can perform in each one. Above you might spot the additional logic operation to allow the pumps to be manually run by holding down a button for 10 seconds - useful for emptying the tank or taking samples from the fuel sampling valve, like the MSA are ever going to implement that fecking rule

 

Finally, then, you combine all of the above into configuration that drives the output pins....

 

You name these yourself again, and then set the logic conditions (or channels) that decide when an output is on or off. If you look in the detail...

 

 

Here we can see the cooling fan motor output channel. A few things configured here - a maximum current which helps protect the circuit (20A probably too high a the moment but I haven't got round to testing and adjusting that yet ), and should it short/over-current you can set the channel to retry after a few seconds, up to a limited number of retries if you wish.

This output is set to turn the fan on if the water temperature read off the CAN bus goes above a certain value - 90 degrees - but I also have an override button on the dash which toggles the "COOL FAN CH" channel, and the fan will also run depending upon the state of this channel. Useful for coming off-stage or pre-empting hot conditions like while queuing up for the start of the stage.

 

Of course there's no need for such complexity, you can have a simple output pin condition along the lines of...

 

More next week, same time, same bat channel.... maybe...