CTIS and Arduino

[tennmogger]

There are dome lights in some LMTVs?

 

[Awesomeness]

There are dome lights in some LMTVs?

He said dome switch, not light.

I have been working on some 3D printed dome lights that go in recesses for the in the top of the cab. More on that in the coming months.

 

[Plasa]

Can you furnish the sketch to me? I will look at the speed sensor but it should be very simple once I record the speed/pulses info. Will you be making circuit boards for this? I have a lot of experience making them very cheaply so if I can help, PM me. I have new membrane panels for the old ECU for replacement of damaged ones, and have the dome switch parts as well.
Tom

Hello Tom.
I think I will make a circuit board when finish yes. Probably I will put the sketch on the board here, but let's see if it's working. Any info about the voltage of the solenoids?

Christian

 

[m-35tom]

Do you have a working CTIS to measure voltage? I can do it this weekend if no.
Tom

 

[scottmandu]

A Raspberry PI would likely be a better choice, as one could also program CAN communication.

 

[Plasa]

A Raspberry PI would likely be a better choice, as one could also program CAN communication.

Yes maybe, but for a M1078 the Arduino is enough because no CAN bus is available... And for debugging the USB port is more than enough...

 

[Plasa]

Hello again.
Finally I got time to publish a picture. After hours of trial and error (my fault) I finally got the new CTIS to work. I can now set any pressure for emergency, sand, XC and highway mode. Plus I got some info what is the CTIS status, like air tank pressure switch, state of the valves and actual PSI. The system checks every 15 minutes the pressure and inflate / deflate as needed.

I did not change anything in the truck, just plug in the new ECU and that's it... The original pressure transducer work with 5V from Arduino. Now I need to add a manual mode, to manually inflate/deflate and to set the pressures without entering in the program code.

Christian

 

[Third From Texas]

Outstanding job !

 

[m-35tom]

Great, will you be offering the sketch to use Arduino junkies?

 

[319cssb]

Great, will you be offering the sketch to use Arduino junkies?

...Asks the guy who tries to sell every little bit of shiny stuff

 

[m-35tom]

What is that supposed to mean? I only sell my ideas and products, is that a problem for you? I also give away lots of information about source of hard to find parts.

 

[coachgeo]

What is that supposed to mean? I only sell my ideas and products, is that a problem for you? I also give away lots of information about source of hard to find parts.

Am not sure what that member is getting at. Been a moderator and user of bulletin boards like this one for decades and know real well there are vendors who just vendor... be a biz... that pops up just for sales reasons and have a bean counter mentality...... then there are those whom are basically one of us that supports their hobbies and fellows.... maybe it grew into a biz.... but they stilll..... support their fellows... That's the kind of folk most of us like and support back with our purchases..... so far M-35tom seems to fall into that category to me. It's all in the balance.

 

[319cssb]

What is that supposed to mean? I only sell my ideas and products, is that a problem for you? .

What you sell is not a problem to me nor do i care, but don't expect someone to give you their ideas and products for free.

 

[m-35tom]

I fail to see what someone else does with their ideas is any of your business. Nor why you feel you should make the comment you made.

What you sell is not a problem to me nor do i care, but don't expect someone to give you their ideas and products for free.

 

[ramdough]

Arduino is historically an open source platform. I would estimate that most hobbyists share their work freely. In fact I think that the end use Arduino contract says that you can sell your products, but if you do, you have to freely provide your code and schematic.

I for one would love to see the sketch and wiring diagram.

Awesome work!






Sent from my iPad using Tapatalk

 

[Ronmar]

I would be curious what safety precautions are written into the code...

 

[Plasa]

Hello all!
Yes, I am thinking about putting the source code on github or something like that under the GNU GPL license to share it. It is in early state, like a beta version, and I need to make it more universal, not just for my truck. Like putting a manual control and to be able to set every pressure by writing it on the eprom. It should be easier to handle it.

Thank to all of you (espescially Ronmar and Stellaevil and all other that I forget) for sharing the internals of the CTIS, without you I would never start this adventure.

The wiring is quite easy and very simple. I make a screenshot of the eagle schematic.

The relays are placed on a 4 relay board to have 1 spare relay for other function (like overspeed). What I put on safety precautions right now:
- of course low pressure switch, system stop if low pressure
- ambient pressure: in idle state pressure must be < emergency pressure
- min / max pressure: if transducer signal is < 50 (ambient pressure is around 100) or > 1050 (about 100psi) system stops
- if inflate takes more than 30 minutes stops
- if deflate takes more than 20 minutes stops (definitly too long, need to review)
- after reaching correct pressure the system checks after 30 seconds if valves are closed. I saw that deflating takes much less time than inflate. So in 30 seconds there the diffrence is about 20psi
- I put a master switch on it that cuts the 24V, if everything goes wrong
- on the display I see the state of the air tank pressure, all 3 valves (control, inflate, deflate), the actual selected terrain and the actual pressure.
- system checks every 15 minutes the correct pressure, works great also with cold / warm tires.
- max time for emergency is 10 minutes, than goes to sand.
- if terrain changes system starts again from beginning.
- you can bypass the air tank switch by pressing 2 keys together. Great if you are in engine idle and you want to inflate the tires.

What i would like to do:
- The actual pressure is not displayed exactly as the transducer goes from 0 to 1024, but ambient is 100, and 65 psi are not 650.
- create a PCB with everything on board (arduino, voltage regulator and relays)
- try to find a way to pre check if valves are OK (measuring current or resistance), but I have no idea...
- see if I can read the speed signal to avoid overspeed
- what else can be useful?

Thank you again for sharing all the info! It's a great forum!

Christian

 

[m-35tom]

for pressure reading use 'map(pressureValue, 0, 1023, 0, 150);' if you are using a 150 psi transducer in the PSU. I don't know what pressure it is now, but less.
You probably already know this!!

 

[Plasa]

Thank you!
Yes, but I don't know what's the range the original pressure transducer. It's 120 or 150 psi transducer?

for pressure reading use 'map(pressureValue, 0, 1023, 0, 150);' if you are using a 150 psi transducer in the PSU. I don't know what pressure it is now, but less.
You probably already know this!!

 

[m-35tom]

I used a 150 psi transducer to trick the system to air my tires up to 80 psi in hgy setting. Since many people would want to run higher pressures I think you should consider changing the transducer as well plus then you would know what to map it to in the sketch.
Tom