3 knob HVAC control upgrade
04-16-2016, 09:12 AM
#151
Thread Starter
See this for the original thread - https://rennlist.com/forums/928-foru...ign-input.html . And here is a nice install - https://rennlist.com/forums/928-foru...h-journey.html .
05-03-2016, 12:30 AM
#153
Thread Starter
Not a happy update here - it has been since mid January that I have been banging my head on the brick wall, trying to get the added I/O extender chip to behave like it should! Talk about frustrating! Even had some help from a very thorough, experienced guy online, but still no joy. In retrospect, the programming of this chip will probably be extremely complex, with the number of ports to be on/off, yet leave others not affected - the variable matrix was looking scary.
So, took a hard look at the previous style of board design - can I fit all the required interface outputs on the Arduino Nano pins available? Yes, it looks like I can do this, by stacking some pins with different duties, to be determined with jumpers and coding. So, will move forward without the extra I/O chip, knowing I can control relays easily with direct pin coding. This requires a 4th gen of the board, but working on proving all the circuits on breadboard first, before ordering printed boards. I figure 3+ months working on this is enough - give up and find another way to do the job! So far the V4 is simpler and less crowded - always a plus.
So, took a hard look at the previous style of board design - can I fit all the required interface outputs on the Arduino Nano pins available? Yes, it looks like I can do this, by stacking some pins with different duties, to be determined with jumpers and coding. So, will move forward without the extra I/O chip, knowing I can control relays easily with direct pin coding. This requires a 4th gen of the board, but working on proving all the circuits on breadboard first, before ordering printed boards. I figure 3+ months working on this is enough - give up and find another way to do the job! So far the V4 is simpler and less crowded - always a plus.
05-21-2016, 09:23 PM
#155
Thread Starter
With the number of pins on the Arduino Nano maxed out, and no extra outputs available for end user customization, I was surfing for options, and found the Teensy 3.2 board. It has more I/O pins, more PWM pins (still 3 timers), direct DAC, 2 ADC's, and uses a much more powerful processor with 8X more memory! A whole lot of positives for it, so seriously looking at my ongoing V4 redesign and switching over to this Teensy processor. Wish I had found this back in December - would have saved 3+ months of headache with the I/O extender chip battle!
05-22-2016, 04:29 PM
#156
Rennlist Member
With the number of pins on the Arduino Nano maxed out, and no extra outputs available for end user customization, I was surfing for options, and found the Teensy 3.2 board. It has more I/O pins, more PWM pins (still 3 timers), direct DAC, 2 ADC's, and uses a much more powerful processor with 8X more memory! A whole lot of positives for it, so seriously looking at my ongoing V4 redesign and switching over to this Teensy processor. Wish I had found this back in December - would have saved 3+ months of headache with the I/O extender chip battle!
Looking forward to the final product
Cheers!
Carl
05-22-2016, 10:34 PM
#158
Thread Starter
Oh yeah, I'm still at it! Been trying to squeeze all the required functions onto the Nano pins available, and this has caused several iterations of the pinouts to get all the functions covered, with some pins doing double duty. It can work now, but no expansion possible.
Working with my breadboard tester, I have been able to output a variable voltage through a regulator, so next is to hook that up to an electric water valve and try to control it, instead of the on/off of the vacuum controlled valve.
Working with my breadboard tester, I have been able to output a variable voltage through a regulator, so next is to hook that up to an electric water valve and try to control it, instead of the on/off of the vacuum controlled valve.
06-05-2016, 10:55 PM
#160
Thread Starter
Small steps forward.... Finally decided between a PWM amplifier and a MOSFET power transistor for the blower fan speed control - the winner is..... MOSFET! Mainly because the one I have is smaller than the 2 different PWM control modules I have held in my hands, and will fit nicely on the top of the duct, in front of the AC evap coil. It is only 3 wires, 2 large ones that are spliced into the GND side of the motor circuit, and the tiny signal wire which takes a variable voltage from the control to vary the fan speed. Another plus to this setup is there is no PWM frequency noise to tune out - at least not that I have heard so far. Will have a final motor test on my bench test board done with the breadboard assembly in the next couple evenings. At the moment, I can vary the motor speed from about 60 RPM to full speed by just using a 10K pot as a variable resistor on the signal wire - very cool!! My breadboard build is currently putting out 2.1V-10.3V on a cyclic program, and this can be tuned in the hardware with a setting pot, and will be a little higher when running on car battery power. Nice little success yesterday!
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
06-05-2016, 11:09 PM
#161
Rennlist Member
...
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
06-05-2016, 11:34 PM
#162
Thread Starter
Yep, 1 board design with both sizes of AMP edge connectors built-in. Final assembly jumper wires will determine what year 928 it will fit into, or just pinout new pigtail Deutsch DT series connectors to be used in a custom application. Lots of flexability built into this unit.
06-05-2016, 11:37 PM
#163
Rennlist Member
Join Date: Nov 2011
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Small steps forward.... Finally decided between a PWM amplifier and a MOSFET power transistor for the blower fan speed control - the winner is..... MOSFET! Mainly because the one I have is smaller than the 2 different PWM control modules I have held in my hands, and will fit nicely on the top of the duct, in front of the AC evap coil. It is only 3 wires, 2 large ones that are spliced into the GND side of the motor circuit, and the tiny signal wire which takes a variable voltage from the control to vary the fan speed. Another plus to this setup is there is no PWM frequency noise to tune out - at least not that I have heard so far. Will have a final motor test on my bench test board done with the breadboard assembly in the next couple evenings. At the moment, I can vary the motor speed from about 60 RPM to full speed by just using a 10K pot as a variable resistor on the signal wire - very cool!! My breadboard build is currently putting out 2.1V-10.3V on a cyclic program, and this can be tuned in the hardware with a setting pot, and will be a little higher when running on car battery power. Nice little success yesterday!
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
Mike
06-06-2016, 07:42 AM
#164
Rennlist Member
Small steps forward.... Finally decided between a PWM amplifier and a MOSFET power transistor for the blower fan speed control - the winner is..... MOSFET! Mainly because the one I have is smaller than the 2 different PWM control modules I have held in my hands, and will fit nicely on the top of the duct, in front of the AC evap coil. It is only 3 wires, 2 large ones that are spliced into the GND side of the motor circuit, and the tiny signal wire which takes a variable voltage from the control to vary the fan speed. Another plus to this setup is there is no PWM frequency noise to tune out - at least not that I have heard so far. Will have a final motor test on my bench test board done with the breadboard assembly in the next couple evenings. At the moment, I can vary the motor speed from about 60 RPM to full speed by just using a 10K pot as a variable resistor on the signal wire - very cool!! My breadboard build is currently putting out 2.1V-10.3V on a cyclic program, and this can be tuned in the hardware with a setting pot, and will be a little higher when running on car battery power. Nice little success yesterday!
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
Today was spent wishing I was at SITM 2016, and building a bench test setup for the OB system and 84+ system, combined into one board. This will allow me to plug an assembled HVAC control into it, and test all functions before it goes into the field. The upper vacuum relays and temp setting motor are for the pre-84, and the lower is newer system. Just need to wire in the stock hvac harnesses for power/gnd, lighting input from dash reostat, and couple other things to simulate all the car items I'm interfacing with. The bottom right item is an electronic water valve actuator, last component to conquer as a requested item. This will be a variable water valve, instead of the on/off vacuum setup. Will get the wire pinouts of this in the next couple days, and confident I can control it too with a variable voltage.
I see the Thermotion valve
This is so exciting!! So the MOSFET fan controller, is it the Sentra or Mazda unit?Cheers!
Carl
