So I built a few canbus/car electronic projects… anyone got ideas for more?

[Gripless]

Have made some esp32 gauges and displays for my car.

does anyone want something like this or have any suggestions?

 

All these are setup over wifi with webpage to enter settings. It’s pretty basic so far but could add presets to auto configure for different generations.

 

Tire pressure over Bluetooth round display that you turn outer ring to see different pressure units, and push to turn off display. It comes back on for new alerts etc. Can add sensor ID and working on a discovery feature. I theory the 2012 or newer cars could have this canbus the data to the OEM screen. The older cars have a physical wire to the dash lamp.

 

RPM bar display 16-40 led F1 style. Has rpm limits and flash rate etc settings. Currently only canbus but could do pulse counting so works with older rpm signal.

 

DCCD display. Currently no settings just smart watch screen that can show auto with +- manual and the diff lock level. Graphics need a lot of work.

 

canbus keypad. There is a opencan version online so could be auto configured by most aftermarket ecu brands. Or web page where set canbus id and then ecu can receive messages when buttons are pressed. Could also receive messages from ecu to turn on/off illumination behind keys, or set colour.

 

could retrofit a LCD to old cluster so can display more data as well as the check lights so stays WOF compliant.

Edited April 25 by Gripless
Retrofit idea

[Gripless]

Early version of TPMS testing layout and colouring. Currently the magenta lines are grey and text is white unless alarm then red or orange.

 

Screen is 1.3” and outside is about 52mm 

similar size to 08 aircon dials.

Thinking 3 will fit across a single DIN stereo panel size, so could have TPMS, G force sensor and something else.

[Gripless]

Working on prototype 2 for shiftlight.

Prototype 1 was a bench top proof of concept and was just wires with alligator clippers connecting everything.

This one is fully cased with OBD2 connector, and buttons to activate wifi for settings and turn off display etc.

There are 3 options on how to connect the display and sensor to the control box, and where the button(s) are. This one is 3 buttons in the back of the led bar. 

[Gripless]

Tested and working.

25x225mm with 40 led

17x182mm with 32 led 

 

options to set via wifi

redline

flash warning after redline

flash rate/speed

minimum rpm to turn on eg off until 3000rpm. Rescales led so still uses al of them.

pattern. Single line, inside to out, outside to in.

colour palette 

 

thinking of adding canbus id via wifi so can be any ID, plus can send messages from aftermarket ecu telling it how many LEDs to turn on. That way a table or math block in ecu can control it.

[Gripless]

Made a few little changes and fixes.

• better canbus ID filtering
• imcreased processing speed
• watchdog timer that reboots if no can rpm data for 10 seconds
• Small memory leak found that caused issues after 4-5 hours at 2000 packets a second.
• added tiny 1cm wide OLED screen for status information. 

Looks like prototype 2 will be viable for use.

 

The only remaining  issue is triggering the power on and off, but that could be all software sleep.

 

After that is for other people to try it and get feedback 

[Andy_Mac]

Something rectangle that sits in the top 1/3rd of the vents would be cool, like a P3 gauge but with more specialised info available. Having DCCD there would be cool 

[Gripless]

Only sti specific stuff I know of is DCCD and G-force sensors.

 

working on some PCB design bits and updating to use the newer canbus chips.

 

Adding a thermocouple circuit as a test and they cost way to much.

[Gripless]

Well ordered the first circuit boards for prototype 4.

 

WTF cost was USD10 shipped for 10 custom boards.

 

It is insane what you can fit into a tiny space.

The board is 20x76mm and max 5mm high with all these features: 

now 1cm longer and added reverse polarity protection. Plus no need to replace diodes for 24v vehicles.

 

• fuse, self resetting
• short-circuit aka reverse polarity protection 
• 12/24v switch mode power supply for low heat 90% efficiency 
• Just need to swap the fuse for use in 24v vehicles
• Optional ign switch input to power up
• Electrical power noise filtering
• Electrical filtering ADC pins
• Spare 5v and 3v3 volt outputs
• 4x static (ESD)protection for buttons and knobs etc
• 12 general purpose input/outputs
• Current generation CAN 2.0 controller with listen real listen only mode. 
• CAN bus noise filtering, ESD and voltage spike (TVS) protection
• optional canbus termination for aftermarket ecu 2nd bus use.
• ESP32 module with dual core cpu, wifi and Bluetooth 
• connector for firmware update and Arduino IDE supported

This is massive overkill and parts are high spec low tolerance ones.

board can run as almost anything, supports full LCD displays etc. 

 

 

Adding web configuration for colour of each led and rpm it triggers at, mostly done.

You can set can ID and bytes via web to look at so supports most cars and aftermarket ecus. 

Also want to add an aftermarket mode that allows ecu to do some cool things that I have seen any other product do.

 

 

Edited June 27 by Gripless

[Gripless]

Boards have the pins labelled and aren’t locked to custom firmware so can be reprogrammed by anyone.

 

So far estimate around NZD$50 with the LEDs in case as shift light. Main 3 chips are around USD$9

[Gripless]

Have a week or two before the first version turns up and no improvements to make until I can test the board.

 

In the meantime I had the idea I could adapt what I have to a board that plugs into this…

https://www.aliexpress.com/item/1005008877505362.html

that way it’s really cheap to have a canbus connected mini display.
 

Anyone can cut or print a custom front panel or mount it behind a small cutout. Only a few screws hold it together which makes it simple to assemble.

Being shipped from China as DIY no need for certification like CE or FCC for radio(wifi) devices.

That board already has 3 usable buttons (plus reboot) and 3 spare in/out with serial port. 2 is enough for canbus board.

It has place for power in so I just need to do a 12v to 5v section and the protection circuit.

[Timmah]

So, these little gauges can hook into the CAN system and then ... read whatever? Clever! Another reason for me to get a Link..

[Gripless]

5 hours ago, Timmah said:

So, these little gauges can hook into the CAN system and then ... read whatever? Clever! Another reason for me to get a Link..

Pretty much.

The board and chip can read any can up to 1Mb/s speed what you do with it is open to how much coding you can do. The ESP32 that it’s based one has built in canbus support so it’s not as complex as it appears.

 

I’ll have some basic framework coding for it, along with the web config examples. That way there is no need for an app as the ESP32 can be a wifi access point and you connect to it, and it shows the settings.

I have two prototypes running on the OEM stock canbus. One does rpm shiftlight the other is DCCD display.
The tire pressure one hasn’t got off my desk yet as it has an annoying mounting system but it works, mostly. There is no discovery scan yet, you have to know the max addresses of the sensors.

There is another bigger display that is popular CYD 2.8” with touch control for NZD$15-30 as well, that seems like it maybe a good idea to do as well. Power and canbus would be 1/4 to 1/3 that board the rest could be holes for whatever other electronics.

 

[Gripless]

First boards turned up.

waiting on the rest of the components to arrive so can test them.

 

 

 

[Gripless]

Found out bad solder is a thing.

Just had a section of solder wire go on and acts like lead free. Extra flux etc makes no difference, it looks like aluminium burrs even when heated. Problem was it is under the pads on a microcontroller and shorting ground to power. New solder and drowned in flux it just turns to sand like beads and won’t flow. 

 

I tested some more of the roll and it has sections that don’t melt correctly and are matte without shine and do flow or stick to the tip of the iron. The 2-mm from the heated end looks matte and nasty as well. 

 

Ordered new roll of solder so that is more delay.

still have other cool things on the go so back to learning to code.

[boon]

I had a similar experience recently. Thought my iron was faulty, biffed it and bought a flash new one, same result. Annoying to say the least, had to rework a whole bunch of s*** joins on a board afterward.

[Gripless]

16 minutes ago, boon said:

I had a similar experience recently. Thought my iron was faulty, biffed it and bought a flash new one, same result. Annoying to say the least, had to rework a whole bunch of s*** joins on a board afterward.

Also learned that some solder rolls are weighted. Not the solder but the plastic roll. The trick is they use heavy webbing between the hole and the outer layer the solder is rolled on. Some YouTube channel weighed them and more than half the stated weight is plastic

https://youtu.be/lQ91gktACXw

 

[Gripless]

Managed to finally get some more progress as parts arrived last week.

 

I soldered up the switching and regulator power supply using solder paste and heat plate which worked on all but one tiny chip. Solder bridged 2 pins but that was easy to clean up.

I fitted both diodes backwards, one as didn’t check, the other I knew was backwards but was working off old schematic.

 

All voltages were good, so tomorrow I’ll add the can bus section and hopefully the micro controller.

 

I missed ordering the tiny capacitors for the canbus but the voltage sections are overly filtered and won’t impact testing. The static protection chip wasn’t ordered either as that want needed to test.

[Gripless]

Well wasted most of a day chasing an issue with chips not flashing.

Desoldered parts rechecked with multimeter as seemed to be a possible short or something in the design blocking normal boot up.

 

I ended up tacking some wires directly to another microcontroller in the batch I have and it had same fault.

Seems the older chips I got have a higher current draw than my normal programmer supports. Finally dug out an older one and got code to upload ok.

re-soldered everything I removed so tomorrow I’ll try the canbus.

After that I’ll build up another board and fit it into the case with LEDs and light sensor as a finished unit.

 

If this works I’ll order the newest 9th revision and also the power/can board for the tiny LCD screen ones.

[Gripless]

So far, so good.

canbus drivers etc all installed ok.

Also found that every reboot of pc that programs the microcontroller it resets the memory size and partitions where normally it remembers them. This isn’t a big deal but is annoying. A custom board description file will fix the issue, so have to learn that next. It will help with final version for others to customise and install their own software.

 

Tomorrow I have to dig out laptop with the canbus software and usb canbus sticks  and setup a testing network again.

[Gripless]

Basic software testing is now working.

Finally found out one of the wired pins for transmission was not usable. No idea why it’s not marked as any special pin and acceptable for use with canbus controller. It just doesn’t work. Wired another pin and everything just started working ok.

 

Now have a few more tests for the hardware to figure out the resistance values for the pins that control the canbus listen-only and shutdown.

 

You need to balance their internal resistance that wants to make the chip active and transmit the default, vs the external resistors I added to make it shutdown and passive at power up. You need to make the resistance as high as possible to the shutdown passive state as possible that you can overcome with the microcontroller.

 

Tonight will make pcb changes to swap the pin that caused issues to the next closest and add some more places for resistors to both to power and ground. That way swapping resistors can be done on the board as needed. It also allows the canbus controller chip to be a different model that has different need to resistance high or low.

PS figured out some of the download issue were the voltage regulator on the serial port adaptors I have. Using usb supplied 5v through the regulator on the pcb works ok. Guessing they can’t supply enough current as they are cheap and under speced.

Edited July 23 by Gripless

[Gripless]

Well that took far longer than expected.

Prototype 4 fitted into the case with the LEDs and buttons and closed fully. So that’s a win. 

 

I ordered new prototype 9 boards and another selection of components which took a few weeks. Procrastinated a few weeks, plus life things.

 

Assembled the first one over weekend but it didn’t work. managed today to find a small shirt or solder under a diode, and that the main mosfet on the input was faulty. Not caused by the short.

these have the reverse voltage protection and LEDs to show the voltages are good.

Should put it in a case and test this week.

 

Also a board for the 1.44” screen board and parts arrived. Assembled that and initial tests have power supply section working ok. Have to connect it up to the screen etc this week and test the canbus part. It has a small issue with the mounting holes being being under a mm out but the holes are 2mm so that’s a lot. A file will solve that so first 10 or 20 that arrived will have oval holes.

So DCCD displays should be a thing soon. And the microcontroller isn’t locked down so anyone can make it display whatever they like.

 

 

 

Thinking of bringing them all to Flatnats for people to try and get feedback. Plus may have some race cars to test them lined up.

 

[Gripless]

Forgot to note that ordered pcb in different colours to see what the difference is. Each colour flows differently and has a minimum width between component pads it can flow, with green being best.

I tried white and blue this time as the text colour is white on green and blue, but black on the white board. The black text is not as thick or clear as white. The white text is close on both but still best on green.

Worked out option to add a buzzer to play annoying tone when shift light is flashing.

 

Overall little progress, spent a few days doing custom apple HomeKit projects for environment monitoring. This was an early project that was put on hold as the person who wanted it had to make a bunch of choices.
It has some value for automotive where the car when it arrives home connects to apple homekit and sends data. Depending on the car it could be milage and fuel use or just last battery voltage and temps.

 

Realised I need a better test rig as laptop and stack of usb canbus dongles isn’t the best. So made some initial plans for a stand-alone canbus network similar to the below but with SD card for adding real logs. Plus web portal to setup the canubus IDs for the buttons for lights, gears and pedals to emulate along with a rpm and speed estimate. It will have a obd2 plug with 12v power so it is easy to test devices.

 https://www.aliexpress.com/item/1005009344611851.html

Have some work for custom canbus gauge cluster upgrades for older Subarus that have no obd2 or canbus but run aftermarket ecus. All stealth or OEM+ look inside the stock cluster.

 

 

 

Edited August 16 by Gripless

[Gripless]

So many little things still need work.

 

While not needed for functionality I’m making a testing portal over wifi for testing the connections to canbus and led display etc. This will allow both initial testing and end users to check the device is fully functional and test any repairs or changes they make.

There are many variations in how RPM is encoded in canbus messages 

and they will need to be added as options in settings and the above test portal.

Mounting is another area that has to be tested as so far it’s been black foam tape. There are 2 places for a mount either using alloy riv-nuts or square nuts fixed with resin.
The riv-nuts need with only 2 of the 4 petals so they all need cutting before installing which is slow and they take up a lot of space.

The other option is square nuts that are glued in place and I have used them in the past with god results. The other advantage is that it leaves enough space for a layer of protection so if a longer bolt is used it will have some cushioning before it hits the electronics.
 

Most of the testing side came from a way to reduce cost by using a more traditional tube case with a smaller number of LEDs. 

 

[Gripless]

Managed to flash a microcontroller module in a generic test rig I brought with spring loaded sides. It worked fine except that you need to time the grounding of the boot pin and reset at the same time. The board has a button to do that automatically but the first flash timing doesn’t match. After the first flash though the automatic button works consistently.

 

Flashed another blank module that was already soldered to my pcb and its far from ideal too. The 4 pin for power, ground, send and receive connector was great initially when pin header was soldered in for prototyping. For assembly into a case it can’t have the header fitted. I ordered a spring loaded 4 pin pad to deal with this and clipped it on with a clothes peg. But the fast timing on first flash it needs the ground wire and power to be connected after the serial starts. I split power and ground out and it works ok now.

 

So once the pcb is final I’ll likely need to make a test rig pcb that lines up with all the serial and power points. That will have pogo pin so you just place the real pcb on top with a little pressure it’ll connect. Otherwise it wastes 2-5 minutes trying to get it connected and flashed.

It will also reduce cost allowing the led that indicate different voltages to be left off each pcb and only fitted to the test rig.

 

 

After flashing I left the pcb running in wifi setup mode for hours. The heat from the voltage regulator was the highest as expected. It was still only warm and efficiently spreading heat into the pcb via the large copper pad and holes that were added for exactly that purpose.

I retested again the next day and max regulator temp was 42.4c and 24c room temp. Microcontroller was 41c with wifi idle. Wifi takes 300mA max where no wifi drops as low as 40mA so this should be the maximum power use.

 

 

Worked more on another pcb design for a different canbus project. Between design and selection or parts it takes a lot of time. Seems making sure there will always be stock when you don’t use basic parts is important. Adding little extras to the pcb to allow flexibility will hopefully be worthwhile.

 

Been trying to find my spare steer wheel controls as I can’t remember what the button inside where. They feel like silicon pads and not switches. So that could be a nice quick project to have a board made up with nice micro switches.

Edited August 23 by Gripless

[Gripless]

Learned that wire isn’t always copper anymore.

for a project I got some 3.5mm audio cables to cut in half to make the wiring have nice quick change sensors..

 

Since I needed 30+ cables I ordered so that looked like thick cable but they were cotton braid over tiny wire.

Turned out the wire was copper coated aluminium and is absolutely s***  to solder. Wire is not even thick enough to have insulation on each wire just enamel coating.

 

 

For the car projects all the wire I use has braided shielded which seems to only come in oxygen free copper OFC. The braid helps prevent electrical noise but more importantly prevents damage when pulled through the back of the dash etc.