[gwynethh]

Please bear with us as we are not programmers and are new to the Speeduino world. We are hoping to use a DropBear to run our Subaru SVX. Based on FaceBook and other sources, it appears various Speeduinos have been used successfully for most of the OEM ECU applications.
Usage requires various outputs to be reassigned for example boost output (DropBear Grey C1 pin) to operate the Subaru SVX IRIS valve. The IRIS valve changes the inlet manifold/collector air flow based on an RPM setting).
When all is said and done, we come up short by one output for operating the air conditioner clutch solenoid which is part of the OEM ECU service.
We hope to change one unused Teensy INPUT to a low current OUTPUT. The GM Flex Fuel sense line seems a good target as it is not used in the SVX. Per the init.ini file it appear that the Flex Fuel input connects to pin A15 on the Teensy3.5
It has been suggested to modify the “init.ini” file to accomplish this change. The DropBear specific section is “Case 55”

Specifically comment out line 2280 to
//pinFlex = A16; // Flex sensor commented out to disable pin A16 as an input.

And add after line 2298
pinSpareLOut5 = 35; //low current output spare5 //Added to provide the needed extra output for the AC clutch

Note here that Teensy A16 and 35 are the same physical pin.
Also, we wonder if we need to add after line 2785
..pinMode(pinSpareLOut5,OUTPUT); //is this needed note that the other spare outputs are not so defined?


Are we all wet on this? Is there a better method? TIA from a noob on this.

[LPG2CV]

Assuming the engine is flat six cylinder. Could you use a spare injector, and its acompaning mosfet for the ac clutch relay.

If I recall, DropBear is 8+8 channel. Unless it does some trickery with pins for eight channels.

[LPG2CV]

Not saying your wrong

Dropbear does use trickery on ign and inj channels. SPI, so probably not So no reason not to use Flex pin, but you do need a mosfet or some such, as the pin cannot handle the current.

Though .... Does AC have to go through Speedy? Why not just a switch? What does Speedy need to do when AC is engaged?

[gwynethh]

Not saying your wrong

Dropbear does use trickery on ign and inj channels. SPI, so probably not So no reason not to use Flex pin, but you do need a mosfet or some such, as the pin cannot handle the current.

Though .... Does AC have to go through Speedy? Why not just a switch? What does Speedy need to do when AC is engaged?

The HVAC unit sends an AC request to the OEM ECU. In turn and under specific conditions the ECU issues an idle up command then turns on the compressor and sets the OEM radiator fans to high speed. Finally the AC clutch is activated by the ECU and released under hard acceleration.

[gwynethh]

Assuming the engine is flat six cylinder. Could you use a spare injector, and its acompaning mosfet for the ac clutch relay.

If I recall, DropBear is 8+8 channel. Unless it does some trickery with pins for eight channels.

Ya the DropBear does some trickery with the INJ and IGN so the spares there are not available to drive another device. I understand internally the DB uses some multiplexing of INJ and IGN to reduce wiring complexity of the circuit board. (Please pardon my ignorance if I stated that wrong).

[LPG2CV]

There are also more than one type of idle control. Stepper, pwm, On/Off. you will only be using one of them. If not using stepper, (not familiar with DB) and the socket not populated with the driver chip, then use stepper driver Socket/pins and add mosfet. Or pwm idle pins, and there should already be a mosfet.

[gwynethh]

We appreciate the ideas and reminder about needing a driver between Teensy pin 35 and the AC clutch relay. We are thinking that since we do not need the stepper motor sub board, we will make a small ULN2003 board that uses the stepper motor socket pins for +12V and ground. A jumper wire will run from the ULN2003 to the Teensy pin35 and the output to the DropBear Black A4 (otherwise unused by the DropBear.)

[LPG2CV]

Excellent idea I'm not able to advise on the circuit