openinverter forum

I have written some new code to update my existing basic vcu built on perfboard! This new version takes over throttle and regen input duties so I can transmit them to the 2 oi boards using the latest and safest firmware, it also incorporates al my rx8 dash functions and does motor/gearbox speed matching for shifts that don’t rely purely of synchros, will link in the code later once if put it on git hub, obviously the code is open for anyone to use,

But I need some help designing a pcb I can get produced, I have tired using kicad but lost 2 hours and al my patience just designing the power supply I don’t know how you guys do it!

Is anyone interested in helping my for a modest fee?

It basically needs power supply section 12-20v > 5v with diode protection , headers to suit arduino nano r4, can transiviver, 4 low side logic level output fets 2A capable with fly back diode protection, 4 analogue inputs with zener protection, 4 digital inputs with pull down resistors, 2 non inverted opto isolated digital inputs for 12v signals. A serial comms connection, that’s about it,

On a 100x100board with all connectors 2.54mm pitch


If this is too big an ask someone put me straight! Welding and machining are more my thing!
Anyone interested in helping please speak up

Have you tried EasyEDA? If you've already designed the circuit, its fairly simple to draw up, layout and order. Though all these will take time.

I might be willing to do this. Do you have a rough schematic or do you need circuit as well pcb design.

Will take a look at easy Eda later, I don’t have a schematic either to be fair, frustrating thing is it’s a simple circuits I could make on Perf board quicker than drawing a schematic in kicad I was just after something more finished!

Easyeda is… easy I figured it out very quickly and got my first boards made, did not take me long

Same, I'd never designed a PCB before then used easyEDA and now wouldn't even bother with perfboard. If you post your in-progress designs here and/or discord someone more knowledgable will usually point out your mistakes and help.

Thanks guys will give it a go

Ev8 wrote: ↑Thu Apr 23, 2026 1:07 pm I have written some new code to update my existing basic vcu built on perfboard! This new version takes over throttle and regen input duties so I can transmit them to the 2 oi boards using the latest and safest firmware, it also incorporates al my rx8 dash functions and does motor/gearbox speed matching for shifts that don’t rely purely of synchros, will link in the code later once if put it on git hub, obviously the code is open for anyone to use,

But I need some help designing a pcb I can get produced, I have tired using kicad but lost 2 hours and al my patience just designing the power supply I don’t know how you guys do it!
.....

It basically needs power supply section 12-20v > 5v with diode protection , headers to suit arduino nano r4, can transiviver, 4 low side logic level output fets s2a capable with fly back diode protection, 4 analogue inputs with zener protection, 4 digital inputs with pul down resistors, 2 non inverted opto isolated digital inputs for 22v signals. A serial comms connection, that’s about it,
.....

Did you see my ESP32 VCU board?
In latest 2.4 version
Power input 9V to 30V and it can create stable 5V 3A protected by a diode
Internal conversion 5V to 3V
2x CAN bus
3x 12bit analog channels on I2C link
3x heavy duty contactor outputs
1x Cp input to read EVSE signal
1x PP signal to start EVSE
4x General digital outputs capable of PWM
4x general digital inputs
1x piezo buzzer output if you want to use it

It is all packed in a simple Aliexpress plastic case with equally easy to get 24pin connector
https://leafdriveblog.wordpress.com/202 ... esp32-vcu/
I made it in Designspark so i publish it on my github and i can also provide schematic if you need to build it.
https://github.com/arber333/ESP32-VCU

I made V2.4 to run Outlander system components via CAN. It can also communicate to BMS or CHADEMO system.
2.5 version has only one CAN bus but has more inputs and outputs.
I still have some bare boards that i can part for 2.4 as well as for 2.5 version if you like.

I also have in development a new version to run Tesla gen3 charger at 18kW . But that is stil on arrival from JLPCB...

EDIT: Do you already have a schematic and code prepared? I can also make a similar board for Nano R4. It hase the same conditions as esp32 one integral CAN so i can use SPI for the other one...

PM me...

TI Webench is great for power supply designs but only works for TI ICs. Does layout, schematic, and component selection. Hard part is making sure you find the right components and use the right footprints.

current yet un tested due to no hardware vcu code is here: https://github.com/EV8-Steve/rx8_openinverter_VCU.git

should all be be possible on 1 can bus and both prius gen2 boards will be listening to te same can id's broadcast by the vcu

i have tired easyeda and made the powersupply, it will take a while to do everything i guess, much nicer imtergration of jclpcb's library than kicad

Why do you need a buck converter? The nano has one onboard. Vin is 6 - 21V.

I figured a more powerful one was in order to power 5v sensors ect, I have actually looked at the specs of the onboard one!

Automotive 12v systems can regularly see 80v spikes, how long will it last?
This is doing throttle to can? Need to be thinking about safety, not just make it work.

So stick with my power supply section then, is the tvs diode protection sufficient

I'd be looking at something like this, a little pricey but most of the sourcing and layout headache is taken care of inside the ic, being new to this, consider de-bs-ing the design
https://jlcpcb.com/partdetail/54689569- ... /C51957001
Automotive rated, pretty efficient, and has low power modes too.

jrbe wrote: ↑Thu Apr 23, 2026 10:36 pm Automotive 12v systems can regularly see 80v spikes, how long will it last?

Is it still the case with alternator and starter gone?
Don't want to argue against surge protection of course, just wondering.

I've been running with an IC without protection with a maximum input of 18v for over 2 years of daily use. Maybe some of the relays/solenoids could cause spikes still?

johu wrote: ↑Fri Apr 24, 2026 11:08 am Is it still the case with alternator and starter gone?
Don't want to argue against surge protection of course, just wondering.

My understanding is any large relays like contactors, fan, etc. can do this. Large motors like power steering, vacuum pump, etc. can as well.

Down the rabbit hole..
https://www.ti.com/document-viewer/lit/html/SSZT243

https://www.analog.com/en/resources/ana ... noise.html

Then people who do this for a living chiming in on their preferences,
https://www.eevblog.com/forum/projects/ ... rotection/

OK have ha a better play with easy eda, Schematic more or less there (open to tweaks) so much easier chosing components than kicad

Ev8 wrote: ↑Sun Apr 26, 2026 1:35 pm OK have ha a better play with easy eda, Schematic..

Consider adding 100k-220k pulldowns on analog inputs. Letting them float is sometimes ok, but having them pulled low in case something is disconnected and logic being able to see this pulled low below normal range = disconnect / fault in logic vs floating / erratic signals on disconnect.

The 1k series resistors may be a bit high, just a reminder to check that it wont block too much current for say your optos. Your optos look to be out of stock.

Your power supply and optos have chinese datasheets, you able to read these / find ones you can read to verify they will work? 1k on the rpi2040 at 3.3v / 12ma max seems like maybe too much without being able to see specs.

I have updated the opto to TLP281 as the pc817 was a through hole I just happen to have a bunch of here! Will add pull down resistors to the analog inputs so they don’t float if disconnected so my twin pot throttle differential code actually works!

So it would seem easyeda isn’t too bad to learn, have managed to get his far thanks for the recommendation