custom gauge project using x27.168 stepper motor

[87chevy.com]

Little project I'm playing with. I forget what gauge I started from, oil or temp...
Goal is to get canbus data to drive the gauge, but right now its just analog input / sensor input

I removed the old sending unit, measured center to center, measured the stepper motor, modeled it in cad and 3d printed an adapter. Took 2 tries to get the alignment 100%, pretty impressed with that!





I didn't have any more tiny screws on hand, but a rivet had the right diameter.... alignment on point!

I had some prototype circuit board from a previous project and its hole spacing was perfect for the back of the stepper motor... I cut the circuit board to fit, soldered leads to it and finally to the stepper motor... the leads on the stepper motor are very thin gauge and I think would get damaged if I just soldered wires to the back of them. Being they are designed to be soldered to a circuit board.. lets go that route

I did some searching and found some librarys to control the stepper motor and started basic and then expanded... that turned into lots of coding attempts, many hours later and here I am... kinda close to the end of this part ... still need to figure out a few things but pretty cool none the less (to me at least)...

Video showing function test:
Set to a value using the potentiometer, pressed reset as if you turned key on, or restarted truck... gauge resets and goes to current value. Turn knob to end stops, press reset and gauge returns to current value.

short video using potentiometer to drive gauge

Got the gauge code configurable:
so the gauge needle sweep aligns with tick marks on the face
there's an offset so if operating temp is not exactly at 1/2 on the gauge, it can be adjusted so its more visually appealing while still maintaining the 90º sweep
sensor start range for coolant temp sensor

pretty crazy stuff you can do with an arduino nano , stepper motor driver board, stepper motor and many hours

clint

[dmjlambert]

That's fun! What are you going to measure with the gauge?

[87chevy.com]

Originally Posted by dmjlambert

That's fun! What are you going to measure with the gauge?

It would be the temp sender that installed in the vehicle, that's whats cool about this stuff... I eventually want to expand and use canbus or obd2 data to drive the gauge. Or if its LS, maybe swap out and use the 98 style sender.. so it has its own output. From memory, some say the indicator is not vertical (50% on gauge) when at operating temp.... this could simply be coded/tweaked to suit...

You just tweak the code till the sensor values are displayed on the gauge the way you want it.

For temperature sensor calibration.. I would get a pot of water and put the sensor in it along with an thermometer and start to boil it and take readings from both and log it. then put that into the code, upload it and retest.

Pretty cool thing is if you want more range, your not limited to 90º sweep, you can do anything up to 315º degrees with these stepper motors.. of course you would need to make new indicator lines on the gauge, but all about customization..

I'm still playing around with it and many many hours later finally figured out how to get a " buffer" so the indicator doesn't twitch between 2 input values.... previous code, if the input value is teeter-tottering between 2 values, it would read each sensor value and move indicator 1 step either way ... solved it chances are you wont even notice it, but just like anything else, once you notice it, and IF it annoys you, it will annoy you

clint

[87chevy.com]

widdling away at this some more.. connected a L84 temp sensor (spare) to the circuit, added some more code sourced from other posts and the gauge reads from the sensor, need some tweaking on the formula but pretty cool.

also:
added code to turn on an LED if the sensor circuit turns into an OPEN circuit
added code to flash the led if the temperature goes above a certian range on the gauge. like center is 210º, it can be set to the next tick mark which will be hottttt, or inbetween...

Just thought about sensor wire short to ground and short to power.... short to ground shouldnt damage anything, but short to power might damage something since I dont have any overcurent protection on this. might skip that for now..

Ultimate goal woudl be to get the gauge to run off OBD2 port, or even better Can Bus data... Ive got the setup to read canbus, but thats about as far as i got successfully.
another alternate idea is to use this and a digital potentiometer to run the OEM gauge from can bus or OBD2 port. No idea why no aftermarket does this...

little video showing the "over heat' condition blinking the led and the "open circuit" condition making the LED stay on. The LED mentioned is the builtin_led on the Arduino Nano... but really, it will be a LED wired to the Nano and and remote mounted somewhere so its actually useful.. maybe even change the back lighting of the gauge to flash red


http://www.87chevy.com/video/gauge_update-1.mp4

clint

[87chevy.com]

Gauge progress with sensor is about 90% ... so I decided to stop and pick back up on the Gen5 canbus that was kicking my butt.. I was trying to get the Arduino nano setup to turn on an LED when its in reverse...
nailed it (finally after many hours)

www.87chevy.com/video/canbus/X5_L83_Reverse_Canbus.mp4

The Nano cannot power the reverse light bulbs on the truck, there would need to be a relay, or transistor that handles the current of the real reverse light bulbs. Similar to my windshield wiper delay module, the Nano controls automotive relays

then tried the ECU tps data.. nailed it again
LED turns on between 50%-94.5% TPS input

http://www.87chevy.com/video/canbus/...ttle_Range.mp4

This was just a test to see if the Nano could take the canbus data and be able to turn on the LED within a given range... it does.. this will be useful for the A/C control for the L83.
I will have it turn the compressor OFF above a:
desired TPS%
desired:High Side A/C Pressure
desired RPM
and when a condition is met, it will wait 5 seconds between activation

Since the canbus data is values, not a sensor that needs to be scaled and adjusted, I think I will try and combine the canbus project and gauge projects to read and make the gauge move. I'm optimistic, but so easy to miss something simple (ish) and then debug for hours.

clint

[87chevy.com]

super stoked about this... combining 2 sketch's actually worked....
one sketch was the gauge reading a potentiometer or temp sensor
the other was the can bus sketch...

testing this canbus setup on my BMW X5 with 2019 l83 swap, so whats why it doesnt look like a Chevy


http://www.87chevy.com/video/canbus/can_tps_gauge.mp4

Tomorrow to find the actual canbus coolant temp. Im not reading OBD2 pids, Its reading data strait off broadcast can messages...
clint

[87chevy.com]

more hours later... it may not have been a good idea to plug in / un plug the coolant temp sensor trying to identify the change in canbus message. After wasting whit a bit of time trying to see the change... I went back to hptuners and seen that the coolant temp was now the same as intake air temp. Seems like its a fail-safe substitute value or something, clear codes, coolant temp returns to normal expected value (and radiator fan goes back to normal speed.

Few more hours later, I found the coolant temp on the canbus.. Plugged the data into a new sketch, and vola, coolant temp now controls the temp gauge.

now to find oil pressure lol..
after that, design a circuit board for a nano, can bus module and 2 stepper motor drivers so I can have coolant temp and oil pressure gauges

clint

[87chevy.com]

A lot of time later for a little progress...
Found a/c pressure on the can bus but it doesnt update as quick as a PID request.... the period it refreshes varies from less than a second to 3-4 seconds.....

I cannot find oil pressure and battery voltage. I've looked at hp tuners, put in a few formulas to go from kPa to hex and I thought I found it but when I rev the engine, the values go the opposite way... same for battery voltage..

I did however plug in the RPM data to the gauge sketch, success

baby tachometer video

tach is reading raw can data, I havn't found or been able to get any OBD2 pid sketches/programs to work so that's why I'm trying to find the actual can values.

this is what the program sees, all this mumbo jumbo


```
0AA 8 29 CC 34 F8 6 4B 5 0
0D3 2 29 C9
1ED 8 1 F4 0 0 0 0 15 4C
0C7 4 0 0 0 0
0F9 8 0 0 40 0 0 0 0 5
0AA 8 29 CC 34 F8 0 4B 8 0
189 8 0F FF 0F FF 30 1 FF 8C
19D 8 0 0 0 0 0 0 0 FF
1AA 7 1 F4 0 0 0 0 15
1C4 8 82 4 0 8 93 0 3 0
0C7 4 0 0 0 0
0F9 8 0 0 40 0 0 0 0 5
0AA 8 29 CC 34 F8 2 4B 7 0
0D3 2 29 C9
1ED 8 1 F4 0 0 0 0 15 4C
```

well, a whole lot more, this is just a few split seconds of data....

and its basically like finding Waldo lol

clint

[87chevy.com]

going for the long shot here... anyone have links for:
Oil pressure
Battery Voltage (ECM voltage)
been trying for *cough* a while... found some values that change similar to these, but cant find the formula to make it jive.... there is a calculation to turn the raw value into a unit of measurement... i.e. ºf/ ºc, v, psi, kPa...etc..... I just cannot find these
clint

[Getter-Done]

Have you looked at some of the formulas in the Machinist Handbook or Engineering handbooks?

[87chevy.com]

Originally Posted by Getter-Done

Have you looked at some of the formulas in the Machinist Handbook or Engineering handbooks?

would you happen to have a link to one of the books you are referring to?

clint

[Getter-Done]

Here are a few pictures of my go to Books for formulas and info.

They are Mostly (old School stuff) .

They cover a lot of stuff like this.

It even has a Mathematical Formula for concrete strength.

This is why I have been tinkering with stuff like Arduino.

Left to right.
Seventh Edition Machinery Handbook, 11th Edition Machinery Handbook, and Tool and Manufacturing Engineers Handbook.









Your projects are interesting.

Beyond my Normal Projects, I have tested the waters of 3D printing,

I have also ventured in Arduino and Rasp-berry Pi

The code is what pulled me in because in work with CN C machine Pro-Gramming.

The things you have done with the gauge is Cool.



I have a few things in mind like this with a Video camera.

What is your goal with this Research and project?

[87chevy.com]

Originally Posted by Getter-Done

What is your goal with this Research and project?

thanks for the info on books and the complements on the projects
as far as goal, just fooling around for now, but I'd say the goal is to have oil pressure and coolant temp in my truck again..

Dakota stuff if nice, but $$... granted, it works right out of the box.
I like the process of a project and this is interesting but frustrating! I really got into it after the pulse wiper project for the 84-87 trucks that have the wiper controls on the column.

The next project will be getting cruise control back on the gen5 swap.. I just need to get a hold of a newer vehicle for a while and read the data and see if I can find these on the canbus data stream:
Cruise On/Off
Set/Coast -
Resume/Accel +
Cancel

From research it needs the OEM brake pedal sensor for it to work.

today, I just got a sketch working that reads the brake pedal press activation which would be good as a backup redundancy.

clint

[87chevy.com]

Oil pressure sorted out. got a little help on this one. Turns out I found it before, but discarded it because the canhacker program had a 10-15 second delay between readings... but when I put it in the arduino program, it reads / updates no problem.. strange

can_oil_psi_display.mp4

The code is set to turn on the led below 250kpa / 36 psi just to test a low oil pressure condition... works like a champ. Rev the engine and once the oil pressure goes past 250kpa, light turns off, and when it falls below 250, light turns back on.

now to order another stepper motor and driver board and see if the nano can run 2 motors at the same time.

clint

[87chevy.com]

I ordered another stepper motor and driver from mouser.com... amazing service/speed, ordered it Thursday, got it Friday... (there about 3 hours away - that's why its so fast !! )

I wired it up, went back to the x25 examble sketch where you input value from computer to move the gauge and added the 2nd motor code.. it worked pretty cool to see them both work. Next will be to make a sketch an have one gauge read RPM and the other Throttle Pedal... just so I can see the gauges move, vs ... coolant temp and oil pressure (for now)

video link dual_x27_test.mp4

I still haven't found voltage on the canbus stream, found it using obd2 pid request, but rather just steal it from canbus stream. the point of that would be so all 3 gauge needles match. The shaft of the OEM is thin, like a needle, while the x27 stepper motors are like papterclip (thicker). Maybe one could add a shim or something.. haven't sorted that out...

Brothers Trucks is ran or owned by Holley, so I sent Holley an email asking if they sell, or could sell just the gauge face plates by them selves so I wouldn't have to modify original gauges.... and they were like no... I guess they get all their product made and then just sells it as an assembly vs making it in house...

Another thing I'd like to do is see how much custom gauge face overlays are.... then cut out the section off the face plate, like half moon so it can resemble "through the dial lighting" like all modern cars... only problem is the speedo... haven't thought that far ahead.. be pretty slick though..

clint

[87chevy.com]

success, merged 2 canread sketches and it worked (after little troubleshooting in the code)

I forgot to update the needle start position, so its off by by a value in the program by 3 which is why when RPM is 600ish, it shows 500ish on the gauge - quick fix in the code

video link dual_x27_cantest.mp4

I asked a fellow tech at work that has a 2021 Silverado if I could connect to it and try and sniff out some other canbus signals and he said I could once he gets his other ride up and running.

With this Arduino Nano, 2 gauges it the most it can hold (pin wise).... an Arduino Mega has way more pins and would be able to do a full cluster I'd imagine. This little project is staring to cost some money

Im going to look into seeing if they have a mini version of the Mega.... give it a try? But for my initial needs/want was to have an oil pressure and coolant temp without running extra sensors...
mission accomplished !!

Now to shrink it down a bit or atleast make a circuit board that these shields plugs into... that would probably be easier than soldering these little microchips

clint

[Getter-Done]

So once you get the gauge project done,

Are you going to set up a backup camera?

[87chevy.com]

Originally Posted by Getter-Done

So once you get the gauge project done,

Are you going to set up a backup camera?

no way, if I had a back up camera and backed into someone what could I say??
clint

[Getter-Done]

Point made.