GpioShutdownService now also for C4

[joerg]

Link: viewtopic.php?f=137&t=21386

Tested on Voodiks LineageOS16.

[rooted]

You are putting the C4 in your car system?

[joerg]

Not ready with my thoughts. The C4 is for its power supply not compatible with the interface board I made once for the C2. As I looked into the schematic, it can't be supplied by the 5V pins at the 40pin header.

[joerg]

I have tested now an ON/OFF circuit with an ATiny85. It disconnects the C4 from 12V car voltage by a P-Ch Mosfet 10s after a watchdog signal has stopped. When ignition becomes on again, the voltage is switched on for 45 seconds, then watchdog signal must be there to overtake. The watchdog signal is generated by the app. When the C4 is switched off, the Atiny85 goes to sleep and the current goes down to 70uA.
I'm not yet ready with my thoughts. I need to test also a RTC and a PWM for a fan. Why to use a fan? I saw in the specs that it goes to 75°C to throttle. But this is made at 25°C ambient temperature. What is if in summer time the car heats up to > 50°C?

[joerg]

This is a very first design of an interface board, far away from ready.

Bildschirmfoto vom 2020-05-02 19-32-03.png (29.91 KiB) Viewed 2890 times

I would add also
- a reset button that goes to Header.36 and to PB1 to bridge the watchdog for 40 seconds.
- a DS3231 RTC
- a pwm fan transistor

In the power part entry there is a voltage limiter circuit with TVS diode and coil. This would limit voltages above 15 V. The fuse should protect against short circuit, if the diode become faulty due to overload.

[joerg]

As I wrote, I'm not yet ready with my thoughts. I have measured now the current consumption in power off mode, connected the VU7+ and a 4G usb modem. The C4 takes 17mA. The power mosfet in this circuit may not be necessary! With this current it takes around a half year to drain the cars battery. Recommendations are highly appreciated. I am not a car expert. What would happen if I let my car some weeks in winter time. Does it goes on if battery is weak?

[rooted]

It wouldn't hurt the battery, the idle drain of a modern cars electrical system is quite a bit more than 17mA already.

It's not healthy for a car battery to not be used for months without a battery tender hooked up anyway.

[joerg]

I think I made some progress. I would stay with the solution of switch off the power with a mosfet. But I found another way to check if the C4 is powered off. The former solution with a toggle bit lacks some seconds until the C4 is really powered down. Now I connect the 5V pin to the ATtiny. It changes to ~1.5V once it is shut down. The LED acts as indication and as a zener and so ensures that the voltage level is fine for the GPIO of the ATtiny.
Furthermore with the mosfet the C4 can be power cycled. For this I added the switch, a short press reboots the C4 (by the GpioShutdownService App), a long press of > 2s power cycles the C4. I looked to the voltage supplying the C4 to see if there are spikes when I do so, but no, no spikes. This is also only the last option, if driving the car and the C4 does not respond any more.
There is also a connection for a fan. To have the right time immediately after boot, there is also a DS3231 high precise RTC.
I will now strip a board, it takes some time...

C4 Car Interface.png (234.61 KiB) Viewed 2455 times

[joerg]

A step forward. But I will sleep a night about it, before I order from PCB manufacture.
And not so nice that some 3d models are missing. I don't have the skills, better not the patience, to draw the missing ones and add them to KiCad.

C4 Car Interface Top.png (82.91 KiB) Viewed 2626 times

C4 Car Interface Bot.png (59.11 KiB) Viewed 2455 times

[rooted]

I love following your progress and the custom hardware you come up with.

[odroid]

Please consider adding an optical Toslink SPDIF output jack before ordering the nice PCB. I hope I am not too late.
I want to enjoy HiFi sound in my car. Sorry for bothering you.

[joerg]

Please consider adding an optical Toslink SPDIF output jack before ordering the nice PCB. I hope I am not too late.
I want to enjoy HiFi sound in my car. Sorry for bothering you.

You don‘t bothering me, never
Already done, the U4 is a PLT133.

[odroid]

Ah... nice!
I couldn't find the U4 in your schematics though.

[joerg]

Yes, I will update it later on.

[joerg]

Updated the missing 3d models and also the sheet. See above.
I learned how to make the 3d models with FreeCad and integrate them to KiCad. Too much work to draw the models with more details.
BTW. I will wait some parts to check, if I have planned the board correct.

[joerg]

GpioShutdownService works also on Android 10 / LineageOS17.1.

[Technicavolous]

How is this coming along?

[joerg]

It's working: viewtopic.php?f=206&t=39066

[j0hnys]

Hello again!
After a lot of digging and reading I came up with something and I need your help to see if it is ok to use it on my car!

Just some pointers:
1. My Odroid C4 is being powered from my headunit's power so even if I turn off my car it will keep having power for at least 20 minutes after I remove the key (so it has plenty of time to shutdown properly).
2.My 5v power supply (J4.2) is the same so it will also have power for 20 minutes.
3.The 12v power supply will connect to car's lighter which will stop when I turn off the car.

So please can somebody tell me if this going to work????

Odroid C4 Car shutdown.png (33.51 KiB) Viewed 400 times

[joerg]

Hello @j0hnys, please don't try this circuit. It cannot work. If the relay isn't energized and either Q1 or Q2 goes on, than there is a short circuit and something will burn!
Refer to this, my car project circuit as above.
E.g. the car lighter to R1 - D2 - R2 to Header.35. In the app, you put as shutdown pin 24 (wiringpi numbering!), and some big value (in milliseconds) as shutdown delay.
That is some minimal circuit that should work for the delayed shutdown.
Note, that in this case the car voltage stays at the DC-jack and the C4 needs a power cycle to start up again (or a configured wake up pin). That's why in my project there is this Q1 power mosfet, that interrupts the power to the C4.

[j0hnys]

Hello. Thank you very much. So because i have 5v in my car already can i give direct 5v to header 35 when i turn of my car
and not use any resistors or again it needs one? So this way the worst it happens the system stays on?

circuit.png (8.22 KiB) Viewed 388 times

Or it should by like the next diagram to be 3.3v

circuit (2).png (10.78 KiB) Viewed 381 times

[joerg]

The header gpio pins don't support 5V. And you can do it without to connect the 5V to the relay. Just connect the GND to NC, let the NO unconnected and take away the R2.
If the header 35 is configured as input it has internal pull up, so only needed to connect it to 0V to shutdown delayed. The R1 you should use, as it acts as protection.

[j0hnys]

Thank you very much joerg. I will do that as i just need a simple solution for now and i am also putting the drawing in case anyone like me need'

circuit (3).png (8.64 KiB) Viewed 346 times

s it!!!!