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Pump My Ride - Ninety on air


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2 hours ago, Turbocharger said:

Thanks for the plug info, much appreciated 👍 Any idea on these plugs, the electric window switches in a 2002 Defender dash (and a Disco 1 centre console, and late RR Classic - and let's be honest, probably a Metro or Marina too). They look like an elegant way to get inputs that will be glove-appropriate.

IMG_20200621_191631.thumb.jpg.91505836df93c0a7005c1c0485b04e4b.jpg

 

 

The connector keyways on that switch, tell me that it's a rear electric window switch for a Discovery-2 and a Freelander-1

It uses a Purple 6-way connector.

I have these.

.

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Thanks Paul - you have a PM.

Wes - I hadn't appreciated it would be so easy - from the hit&drop info I'd planned to code up the PWM bit, but it does look like I can just power up the solenoid driver on pins 10/11/12/13, then put 12v to pins 1-6 for whichever solenoids I want to play with. Thank you - that'll make the coding easier! Still needs MOSFETs to interface logic to 12v but less need for the inductive flyback protection etc.

Does anyone have an in-situ photo of how the height sensors were mounted on a RR Classic? I think that's what the little 'ear' on top of the radius arm is for just behind the axle (but I'll bet it's a person I'm not that keen on to drill!)

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8 minutes ago, Turbocharger said:

Thanks Paul - you have a PM.

Wes - I hadn't appreciated it would be so easy - from the hit&drop info I'd planned to code up the PWM bit, but it does look like I can just power up the solenoid driver on pins 10/11/12/13, then put 12v to pins 1-6 for whichever solenoids I want to play with. Thank you - that'll make the coding easier! Still needs MOSFETs to interface logic to 12v but less need for the inductive flyback protection etc.

Does anyone have an in-situ photo of how the height sensors were mounted on a RR Classic? I think that's what the little 'ear' on top of the radius arm is for just behind the axle (but I'll bet it's a person I'm not that keen on to drill!)

I'll have a look. Definitely have some - whether I can find them is another matter entirely...

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9 minutes ago, Turbocharger said:

Thanks - nothing more complex than holes in the chassis and a tab on the trailing arm then. I can do that 👍

Nope. In truth the entire system is pretty straightforward - nothing like it's reputation for voodoo. Although the controller on the classic is a little eccentric (they seemed to have finished beta testing by the time the P38 came out).

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  • 4 weeks later...

A month on, and a little progress between other distractions.

I have a little MOSFET circuit to take 5v from the Arduino to 12v to drive the solenoids at the high-side. It's specced to drive the compressor too, if it's needed further down the line, but for now the unassuming 'click' with the red LED shows that I can drive a big voltage with a small voltage - I'm learning something, at least. The potentiometer mimics a height sensor, the green LED is for 'inflate' and red is for 'deflate', which is the solenoid that's clicking.

https://youtu.be/0a5vEektG5k

I've also got a fixing for the rear airbag - fronts are on the milling machine now, and I'll remake the rears to tidy them up I think.

https://youtu.be/cbXoZAI3StA

I'm keen to secure at least one end of each bag but they'll fail if the two ends come too far apart so they need to be restrained by the shock travel, regardless of whether they're pulled apart mechanically or pushed apart by the internal pressure, so I could mirror the security of the coils and only hold one end. Any thoughts?

Edited by Turbocharger
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6 minutes ago, Turbocharger said:

A month on, and a little progress between other distractions.

I have a little MOSFET circuit to take 5v from the Arduino to 12v to drive the solenoids at the high-side. It's specced to drive the compressor too, if it's needed further down the line, but for now the unassuming 'click' with the red LED shows that I can drive a big voltage with a small voltage - I'm learning something, at least. The potentiometer mimics a height sensor, the green LED is for 'inflate' and red is for 'deflate', which is the solenoid that's clicking.

https://youtu.be/0a5vEektG5k

I've also got a fixing for the rear airbag - fronts are on the milling machine now, and I'll remake the rears to tidy them up I think.

https://youtu.be/cbXoZAI3StA

I'm keen to secure at least one end of each bag but they'll fail if the two ends come too far apart so they need to be restrained by the shock travel, regardless of whether they're pulled apart mechanically or pushed apart by the internal pressure, so I could mirror the security of the coils and only hold one end. Any thoughts?

The second video is private John 😧

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On 7/21/2020 at 6:14 PM, Turbocharger said:

I'm keen to secure at least one end of each bag but they'll fail if the two ends come too far apart so they need to be restrained by the shock travel, regardless of whether they're pulled apart mechanically or pushed apart by the internal pressure, so I could mirror the security of the coils and only hold one end. Any thoughts?

On a P38 they're secured with a pin on both ends. You can't really dislocate them, as they'll just pop apart from the internal pressure. So I'd go for safe and fix them. Or go for some strange hybrid like an X-spring above the bag 🤔

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I've seen plenty of pictures of Tomcats running with a check strap between the chassis and axle to limit travel. Wouldn't that be suitable?

Limited by shock travel would be ideal, what sort of variability in shick lengths are there? P38 bags are inboard of the chassis rails as standard, but I don't think the chassis rails are parallel.

 If they are closer to the centre than the spring/bag position on RRC/Defender/Disco1 then you may get over travel on articulation rather than symetric bounce?

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14 hours ago, mad_pete said:

How did you make those mounts ? They are cool.  I only held my Range Rover air springs On at one end. I think the shocks should cover it ?

That one is just a piece of box with three overlapping holes cut into it, but I'm not happy so v2.0 is on the milling machine for a tidier result.

IMG_20200723_101457.thumb.jpg.2155ef63764b779658f151d99c18515f.jpg

4 hours ago, elbekko said:

On a P38 they're secured with a pin on both ends. You can't really dislocate them, as they'll just pop apart from the internal pressure. So I'd go for safe and fix them. Or go for some strange hybrid like an X-spring above the bag 🤔

I think that's my question - it's no 'safer' if they're bolted to the chassis or not when it comes too far apart, so therefore it doesn't matter?

3 hours ago, WesBrooks said:

I've seen plenty of pictures of Tomcats running with a check strap between the chassis and axle to limit travel. Wouldn't that be suitable?

Limited by shock travel would be ideal, what sort of variability in shick lengths are there? P38 bags are inboard of the chassis rails as standard, but I don't think the chassis rails are parallel.

 If they are closer to the centre than the spring/bag position on RRC/Defender/Disco1 then you may get over travel on articulation rather than symetric bounce?

A check strap (or shorter shock) is a backup option, my shocks are fairly long to maximise the travel. Shocks are slightly outboard of the bags so straight 'heave' (rather than articulation) should be the worst case. 

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6 hours ago, WesBrooks said:

P38 bags are inboard of the chassis rails as standard, but I don't think the chassis rails are parallel.

 If they are closer to the centre than the spring/bag position on RRC/Defender/Disco1 then you may get over travel on articulation rather than symetric bounce?

The chassis rails on a P38 are further out towards the sides of the vehicle - and remember the RRC had the option of EAS on pretty much the same geometry as the defender. 

RRC air springs are also secured at both ends. 

With a dislocating air spring would there be any issues with it getting out of shape and failing to relocate properly? Probably only possible if the spring was deflated? 

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More electric spaghetti but it looks more complicated than it is - the Arduino voltage regulator and the solenoid driver are now on the Veroboard and I'm using a real height sensor. The circuit just needs duplicating for the other solenoids and probably another for the compressor. (I could even drive the compressor at variable speed depending on the pressure in the tank, but that's probably one for v5.0!) 

HCSDjJV4Z_iJL1CYWdMcaXvNXaCK00Fm7YTXEwRh562k2ou8YWirIBUkt4umjhEXdpSTyKgCXzv2Ka6BJWbiN43NPPuL7DSPdAeB3ScA-7YvzN7jQgsKABbprkjAKVBMjgB-Q8AR5f_C11JvNq2W9iqH_4ZpxlW1OKsYjwRFjCwCaLegpf0DsqAeC8OSEske3XxK2n81ZQcAkOi-fATkwoe_6Z_K8mW8XbygeWpbjeGjjIT0V7-UCwnAgbmO9EnRyBG3fpXxi6-aB6JWgzxXDKYClPrWue7QlzOHhG2IEkcBiv9LT0vteAFud1s08gkEYen26LEO6b3KzILjWVT2KoIMpyCSTfIPMYjMlMR56PqtDYVcqV3d0HTpbCcTUDBj1JJ9ZFlcpM6Qy8lG3c9Lj8yXj5I9K28fllQMCC5lESpRnYmt5ggh2Qa_WZD0M24gMU6RG_Ix2Ooik7HI15OKGujGIObFSV1Td7AoldUTqa3SWnVN8XCSIiqhA-0q2dmxd3UfP8Vs64Ef5hLhfWE5zqdDAL3ozIPXE21CLVp3-uYt8vI6_w1yaoyTPfNIVOIxic-15yyCCbvxj7Mhc3dIWuEd0CkKIztcXlMPAthk_rnpZ0qL5t6RVw7ji-bgVrloJv9sQ2SLfsZYZMQieCLhnzjlqg2Qce76tleOhmAjwExH4jxMs3QWVb609m5LFBo=w1250-h937-no?authuser=0

Much more boring work to do, little tasks that don't look like big progress - then suddenly with one more job it'll look like progress again.

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Waiting for some electronic bits to turn up now, so I whizzed up a couple of lower spring plates on the mill. These are temporary (probably) but will support the lower spring seat and could be faced at an angle to help offset the effect as the axle rotates on full droop, which is tending to 'peel' the lower spring seat out of the bag.

The mill is new to me but pretty pleased with how this turned out, the bolt pockets neatly the right width to make the bolt head captive too. (The speed holes around the edge are definitely to reduce unsprung weight and to look cool, nothing at all to do with using old lumps of alu from the offcuts bin at all, oh no).

IMG_20200802_150349.thumb.jpg.627d8e03f598692bb12dee832bc3b663.jpg

IMG_20200802_160122.thumb.jpg.bb9342b2b323a76dd7329aea5bcbc106.jpg

I've decided to built the control as a daughter board onto an Arduino Pro Mega - essentially an Arduino chip, but the Mega has 16Mhz processor, 54 digital IOs and 16 analogue channels - that should be plenty even if I decide to put accelerometers on each wheel! The Pro Mega puts this onto a PCB which is 55 x 38mm and has pins at 0.1" spacing for use with breadboards - and all for £7, which is the really impressive part!

Edited by Turbocharger
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