Arduino for in-car air management.

I'm working on a pneumatically operated pop-up multi function audio controller to go in my car.The control (up/down) of the controller I've already done using discrete components.

I'd like a separate Arduino based system to manage the air if at all possible.I'd like electronic monitoring of the pressure inside the air tank,the ability to alter the compressor's switch-on and switch-off pressures and the ability to purge the air from the tank at the end of the day.I'd like this all to be accessed via a small touch screen somewhere in the front of the car.At the moment I'm using a conventional diaphragm type of pressure switch to control the compressor,but even being adjustable it still only allows me to set a single on/off switching point.

I can handle the electronics part of it with my eyes shut,but I really struggle when it comes to writing any sort of computer code,so will need quite a bit of help with this one please.

Just to sum it all up quickly,this is purely for air management to do with the compressor and tank.Switching the various solenoids is already taken care of and is something I really want to keep separate from the air management.

You say manage the air, do you mean the A/C system, suspension airbags, an air tank for a horn, or what are you looking to really do?

So you have a compressor with an air pump, that is set to a desired amount, but you want it to be able to be set to multiple amounts(variables).

How much air pressure are we talking about? Are you using a solenoid operated purge, or a ball valve with a servo attached or what is the dump valve? Have you figured out how long in takes to dump the pressure, do you want the program to verify through inputs that the pressure has been relieved?

Not air ride or air con,one of these…

I only need about 1.5 BAR regulated maximum to work the actuator,but the tank can be storing 7-8 BAR or as much as it can safely take.The more air stored in the tank,the longer before the compressor has to switch on to top it up again.

I’ve already got 4 X 12 Volt solenoid valves to operate the actuator,but as these don’t like more than a couple of BAR,I’d be using a heavier duty version of the same sort of thing to do the purge.I know it’ll purge anyway in less than 10 seconds (it’s only a small disposable MIG welding gas bottle),but I can monitor the pressure on the display just to make sure.It doesn’t HAVE to be purged as it won’t do any harm if I leave it at full pressure,but it would be a neat touch to be able to do it just in case.One touch purge would be even nicer as I’m sure this can’t be all that difficult to do once the Arduino is already in control.

A quick bump for this one if anyone has got any ideas on this please?

From your description so far, I am finding it difficult to understand exactly what your system is required to do, and also what help you actually require.

JohnLincoln: From your description so far, I am finding it difficult to understand exactly what your system is required to do, and also what help you actually require.

Thanks for the answer but I'm not sure if I can describe it in any more detail than what I've already given.

An air pressure sensor connected to the tank sends it's data back to the Arduino which then displays this pressure on the screen.I can set the turn on and turn off pressure from the screen.I can purge the air out of the tank from the screen and I can initiate refilling of the tank from the screen.All I need to come out of it is an output to drive a relay to control the compressor,and an output to drive a relay to energise a solenoid to purge the air tank.

Sunday morning bump.Come on guys,why is it so hard to get any help on here,what's the point of a support forum if you don't give people the support they need to use the product? 92 views and the only answers so far have been asking me to repeat what I've already said.

It sounds like you need to replace the pressure switch with a pressure sensor. You could monitor the sensor value with one of the analog inputs, and use that to decide when to start/stop the compressor.

I've not personally used an arduino touch screen, but they look to be well supported.

Just out of interest, are you the same Imagewerx from Talk Audio and a certain VW forum ?

Cheers,

Ian.

Do you need help selecting a pressure sensor? You confidently say you have the electronics all sewn up but it seems this component is missing.

ian332isport: It sounds like you need to replace the pressure switch with a pressure sensor. You could monitor the sensor value with one of the analog inputs, and use that to decide when to start/stop the compressor.

I've not personally used an arduino touch screen, but they look to be well supported.

Just out of interest, are you the same Imagewerx from Talk Audio and a certain VW forum ?

Cheers,

Ian.

Thanks Ian but I did figure that bit out,it's the writing code part of this that I'm stuck on.

Yes I am the same person from a 'certain VW forum' and Talk Audio,although I haven't been on the latter one for some time now.Still into my car audio in a big way though with a digital photo frame (Openpeak Joggler) as a signal source.

MorganS: Do you need help selecting a pressure sensor? You confidently say you have the electronics all sewn up but it seems this component is missing.

Not really as it's easy enough to find one by typing 'Arduino air pressure sensor' into eBay.But if there's one out of all of them that's known to work better than the others do,that would definitely be of some help.

Oh and by the way,it's an Arduino Uno if that makes any difference.

An Uno should be a good platform for this.

So, which sensor are you using? Can you give us a link to the datasheet? If you have tried to write some code then show us the sketch and tell us what it actually does when it runs and what you expected it should do.

Use [ code ] tags when posting code.

I haven’t got a sensor yet. The problem is the passive pressure switch I’m using at the moment only has a single but adjustable on/off pressure setting.I either need two the same or what I’ve ordered is one with preset but staggered on/off pressure switching points,in this case on at 90 PSI and off at 120 PSI.This will probably work just fine and do exactly what I need it to do,but I also want a remote pressure gauge at the front of the car.If I’m going to the trouble of building something electronic to do this,I might as well go the whole hog and make it into an air management system as well.

I haven’t got as far as trying to write any code yet because I can’t.For some reason it’s one of those things my brain just can’t process :sob: .

Imagewerx:
Thanks Ian but I did figure that bit out,it’s the writing code part of this that I’m stuck on.

Yes I am the same person from a ‘certain VW forum’ and Talk Audio,although I haven’t been on the latter one for some time now.Still into my car audio in a big way though with a digital photo frame (Openpeak Joggler) as a signal source.

I thought it may be you. I’ve not been on either forum for a long time (sold the Golf), but still into my car audio. All my arduino tinkering is actually directed towards car audio projects. As it happens, I think you only live up the road from me. I’m down in Cowfold.

As long as you select a sensor that outputs 0 to 5v, and has a working pressure range that suits your desired tank pressure, you should be fine. 0 to 5v on an analog input maps to an integer value from 0 to 1023. If you monitor the analog input value, you’ll know the current tank pressure, and can act accordingly.

This value can be used to switch the compressor on/off, and also displayed on the display etc.

Cheers,

Ian.

ian332isport: I thought it may be you. I've not been on either forum for a long time (sold the Golf), but still into my car audio. All my arduino tinkering is actually directed towards car audio projects. As it happens, I think you only live up the road from me. I'm down in Cowfold.

As long as you select a sensor that outputs 0 to 5v, and has a working pressure range that suits your desired tank pressure, you should be fine. 0 to 5v on an analog input maps to an integer value from 0 to 1023. If you monitor the analog input value, you'll know the current tank pressure, and can act accordingly.

This value can be used to switch the compressor on/off, and also displayed on the display etc.

Cheers,

Ian.

I remember you now Ian,I'm up in Crawley and have still got the red R32 if you were a member 3 years ago?

Will the sensor have to be one of these......

http://www.ebay.co.uk/itm/BMP180-3v3-5v-5-Pins-I2C-Digital-Barometric-Pressure-Sensor-Module-Arduino-Raspi-/251744416712?hash=item3a9d22f3c8:g:VAoAAOSwWKtUr6nI

Or can it be one of these..........

http://www.ebay.co.uk/itm/New-3Pcs-DIP-Air-Pressure-Sensor-0-40kPa-DIP-6-For-Arduino-/121867874155?hash=item1c5fe42f6b:g:EAgAAOSwqYBWm52g

The latter would be easier to use.The former would need the whole board mounting in an airtight enclosure wouldn't it?

Can I be REALLY cheeky and ask a favour if you don't mind? Can you either write this for me please,or at least if there's an existing one (I did look) I can modify to do what I need it to do?

Hi,

Yes, I remember your Golf. Very nice. I had a 2.3 V5, but sold it several years ago. I've got a very modified E30 BMW 325i Sport with M3 Evo engine for playing around in, and an E46 330D Touring for my daily.

Something along the lines of the second sensor would do, but it maxes out at 40kPa, which is a little under 6psi. What sort of pressure will you be needing ?

I'm sure there's others, but Honeywell appear to have a variety of options:

Honeywell Pressure sensors

I can sort out some code when we identify a suitable sensor.

Cheers,

Ian.

As much pressure as it will safely hold,although pointless doing 20 BAR just for the sake of it.I reckon on about 6-7 BAR,but I can play with it once it's all up and running.The actuator only needs 2 BAR maximum to work,but it's nice to have lots of spare air in the tank so the compressor won't need to run very often.

This one looks like it'll be ideal.I hope I've got the units correct-1 Mpa (Megapascal) is 145 PSI?

http://www.ebay.co.uk/itm/0-5-4-5-VDC-0-1-2-MPa-Pressure-Transducer-Sensor-Oil-Fuel-Diesel-Gas-Water-Air-/321817733450

This is good as I'm using a manifold that this will screw straight into.

Yep, that should do nicely :)