3 knob HVAC control upgrade
06-22-2016, 12:08 AM
#181
Pro
Thread Starter
I haven't mad Wizard status yet - maybe in my next life....
Still working on this - V4 board design is ~97% done, just need to calculate voltages at various analog inputs and limit those to 3.3V max, then recheck all my circuits and how they interface to the car harnesses.
Last thing to prove is the control of the stock setting motor with my drive circuit - waiting for me to get some time to focus on that with my test board setup.
Still working on this - V4 board design is ~97% done, just need to calculate voltages at various analog inputs and limit those to 3.3V max, then recheck all my circuits and how they interface to the car harnesses.
Last thing to prove is the control of the stock setting motor with my drive circuit - waiting for me to get some time to focus on that with my test board setup.
07-17-2016, 11:47 PM
#182
Pro
Thread Starter
Not to sound cliche - but "I HAVE CONTROLLLLL!!" I can control the stock setting motor with my programmable circuit!! This was the last challenge in the design - so very pleased with this today! Design progress is in the finest details now for V4 board, and had a revelation last week about the temp sensing circuit - why use the stock system? It is old, and many are troublesome. So decided to include a temperature sensor on the board - this makes it much easier to setup Auto temp control if it is wanted. The only downside is the button with "AUTO" on it and the "Temperature" button are from Nissan Altimas, so one of those controls would need to be sourced to get just those buttons - those are not as common as the Sentra units.
So a quick list of the design features;
- Direct fit replacement for stock 928 control. Also able to fit in a custom situation with just a face housing change. Only the older Sentra ***** will work with the stock replacement fitup. The newer (larger with chrome trim ring) can be used in a custom setup, but won't fit in the space for a stock setup.
- Four fan speeds directly controlled from the unit, plus another single 20A relay for the rear blower if desired. The fresh air relay will work as original.
- Variable fan speed control is also built-in, just add a fan amplifier into the wiring to control the blower, and mount it in the airflow after the fan to dissipate heat. Same for the rear blower too - also built-in.
- User selectable Red or Blue button and background lighting, dimmable from either the stock rheostat, or Ed'd LED controller.
- Can control a variable electric water valve for those that want to control the heat input that way. Tested with Kysor electric water valve, good to -40C.
- Control the stock setting motor so the secondary functions also work as 928 original. Max AC turns off the water valve solenoid, and safety default can be configured for full open on the valve if the system fails.
- On-board temp sensor circuit means the old 928 sensors can be ignored, if Auto temp control is wanted. Just writing code for the Auto function will be a challenge.
- Three extra 1A relays are available for external functions (configurable as either NO or NC), plus a 12V/300mA transistor if faster control is required.
- A 10A relay with extra large traces on both sides of the board for the AC compressor circuit, under program control.
- A DAC output is available - 12bit, and 0 - 3.3V range, but very small current - good for signal out to an op-amp or voltage regulator.
- CANbus TX and RX are available on the board, but I will not be doing any programming for that - out of my league there!
- I'll probably add a tiny fan to the housing to draw air past the temp sensor.
- A MOD button will be part of the front board - I plan for this to act like a "SHIFT" key - when held down, the other 3 buttons and ***** can be operated and have different outputs or functions, all defined by programming.
That's it - a study in "scope creep" if there ever was one! I'm hoping this is flexible enough design for use in other cars that have the solenoid vacuum controls. Next is to order the V4 board, and a set of components for a test board assembly.
So a quick list of the design features;
- Direct fit replacement for stock 928 control. Also able to fit in a custom situation with just a face housing change. Only the older Sentra ***** will work with the stock replacement fitup. The newer (larger with chrome trim ring) can be used in a custom setup, but won't fit in the space for a stock setup.
- Four fan speeds directly controlled from the unit, plus another single 20A relay for the rear blower if desired. The fresh air relay will work as original.
- Variable fan speed control is also built-in, just add a fan amplifier into the wiring to control the blower, and mount it in the airflow after the fan to dissipate heat. Same for the rear blower too - also built-in.
- User selectable Red or Blue button and background lighting, dimmable from either the stock rheostat, or Ed'd LED controller.
- Can control a variable electric water valve for those that want to control the heat input that way. Tested with Kysor electric water valve, good to -40C.
- Control the stock setting motor so the secondary functions also work as 928 original. Max AC turns off the water valve solenoid, and safety default can be configured for full open on the valve if the system fails.
- On-board temp sensor circuit means the old 928 sensors can be ignored, if Auto temp control is wanted. Just writing code for the Auto function will be a challenge.
- Three extra 1A relays are available for external functions (configurable as either NO or NC), plus a 12V/300mA transistor if faster control is required.
- A 10A relay with extra large traces on both sides of the board for the AC compressor circuit, under program control.
- A DAC output is available - 12bit, and 0 - 3.3V range, but very small current - good for signal out to an op-amp or voltage regulator.
- CANbus TX and RX are available on the board, but I will not be doing any programming for that - out of my league there!
- I'll probably add a tiny fan to the housing to draw air past the temp sensor.
- A MOD button will be part of the front board - I plan for this to act like a "SHIFT" key - when held down, the other 3 buttons and ***** can be operated and have different outputs or functions, all defined by programming.
That's it - a study in "scope creep" if there ever was one! I'm hoping this is flexible enough design for use in other cars that have the solenoid vacuum controls. Next is to order the V4 board, and a set of components for a test board assembly.
07-18-2016, 12:40 AM
#183
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Not to sound cliche - but "I HAVE CONTROLLLLL!!" I can control the stock setting motor with my programmable circuit!! This was the last challenge in the design - so very pleased with this today! Design progress is in the finest details now for V4 board, and had a revelation last week about the temp sensing circuit - why use the stock system? It is old, and many are troublesome. So decided to include a temperature sensor on the board - this makes it much easier to setup Auto temp control if it is wanted. The only downside is the button with "AUTO" on it and the "Temperature" button are from Nissan Altimas, so one of those controls would need to be sourced to get just those buttons - those are not as common as the Sentra units.
So a quick list of the design features;
- Direct fit replacement for stock 928 control. Also able to fit in a custom situation with just a face housing change. Only the older Sentra ***** will work with the stock replacement fitup. The newer (larger with chrome trim ring) can be used in a custom setup, but won't fit in the space for a stock setup.
- Four fan speeds directly controlled from the unit, plus another single 20A relay for the rear blower if desired. The fresh air relay will work as original.
- Variable fan speed control is also built-in, just add a fan amplifier into the wiring to control the blower, and mount it in the airflow after the fan to dissipate heat. Same for the rear blower too - also built-in.
- User selectable Red or Blue button and background lighting, dimmable from either the stock rheostat, or Ed'd LED controller.
- Can control a variable electric water valve for those that want to control the heat input that way. Tested with Kysor electric water valve, good to -40C.
- Control the stock setting motor so the secondary functions also work as 928 original. Max AC turns off the water valve solenoid, and safety default can be configured for full open on the valve if the system fails.
- On-board temp sensor circuit means the old 928 sensors can be ignored, if Auto temp control is wanted. Just writing code for the Auto function will be a challenge.
- Three extra 1A relays are available for external functions (configurable as either NO or NC), plus a 12V/300mA transistor if faster control is required.
- A 10A relay with extra large traces on both sides of the board for the AC compressor circuit, under program control.
- A DAC output is available - 12bit, and 0 - 3.3V range, but very small current - good for signal out to an op-amp or voltage regulator.
- CANbus TX and RX are available on the board, but I will not be doing any programming for that - out of my league there!
- I'll probably add a tiny fan to the housing to draw air past the temp sensor.
- A MOD button will be part of the front board - I plan for this to act like a "SHIFT" key - when held down, the other 3 buttons and ***** can be operated and have different outputs or functions, all defined by programming.
That's it - a study in "scope creep" if there ever was one! I'm hoping this is flexible enough design for use in other cars that have the solenoid vacuum controls. Next is to order the V4 board, and a set of components for a test board assembly.
So a quick list of the design features;
- Direct fit replacement for stock 928 control. Also able to fit in a custom situation with just a face housing change. Only the older Sentra ***** will work with the stock replacement fitup. The newer (larger with chrome trim ring) can be used in a custom setup, but won't fit in the space for a stock setup.
- Four fan speeds directly controlled from the unit, plus another single 20A relay for the rear blower if desired. The fresh air relay will work as original.
- Variable fan speed control is also built-in, just add a fan amplifier into the wiring to control the blower, and mount it in the airflow after the fan to dissipate heat. Same for the rear blower too - also built-in.
- User selectable Red or Blue button and background lighting, dimmable from either the stock rheostat, or Ed'd LED controller.
- Can control a variable electric water valve for those that want to control the heat input that way. Tested with Kysor electric water valve, good to -40C.
- Control the stock setting motor so the secondary functions also work as 928 original. Max AC turns off the water valve solenoid, and safety default can be configured for full open on the valve if the system fails.
- On-board temp sensor circuit means the old 928 sensors can be ignored, if Auto temp control is wanted. Just writing code for the Auto function will be a challenge.
- Three extra 1A relays are available for external functions (configurable as either NO or NC), plus a 12V/300mA transistor if faster control is required.
- A 10A relay with extra large traces on both sides of the board for the AC compressor circuit, under program control.
- A DAC output is available - 12bit, and 0 - 3.3V range, but very small current - good for signal out to an op-amp or voltage regulator.
- CANbus TX and RX are available on the board, but I will not be doing any programming for that - out of my league there!
- I'll probably add a tiny fan to the housing to draw air past the temp sensor.
- A MOD button will be part of the front board - I plan for this to act like a "SHIFT" key - when held down, the other 3 buttons and ***** can be operated and have different outputs or functions, all defined by programming.
That's it - a study in "scope creep" if there ever was one! I'm hoping this is flexible enough design for use in other cars that have the solenoid vacuum controls. Next is to order the V4 board, and a set of components for a test board assembly.
07-19-2016, 07:19 PM
#184
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Excellent work! Please put me on the list when they are ready for prime time. I am still a little unsure, will the end result be plug and play? Or will I have to buy/mod additional items (fan controller, relays, electric water diverters, wiring harnesses, etc.).
While I am fully capable (with right instructions) of doing anything mechanical/wiring. I was hoping to unplug the current module and plugin new one? Something in between?
Thanks again for your work on this.
I have a 93 GTS with rear air if that helps answer any questions specifically for my car.
Tony
While I am fully capable (with right instructions) of doing anything mechanical/wiring. I was hoping to unplug the current module and plugin new one? Something in between?
Thanks again for your work on this.
I have a 93 GTS with rear air if that helps answer any questions specifically for my car.
Tony
07-19-2016, 11:05 PM
#185
Pro
Thread Starter
The goal is plug and play for those that want to keep the stock functionality. It fits in the stock space and mounts the same. If you want to convert to infinite fan speed control, then a fan amplifier will need to be sourced and installed into the airflow after the fan, and an adapter harness will be needed for this option. I'm considering making those here (or sourcing them from a harness manufacturer).
An unknown at this time is the rear air system - specifically the temp control and how it works. I'll be digging into that next.
An unknown at this time is the rear air system - specifically the temp control and how it works. I'll be digging into that next.
09-30-2016, 08:37 PM
#187
Not to sound cliche - but "I HAVE CONTROLLLLL!!" I can control the stock setting motor with my programmable circuit!! This was the last challenge in the design - so very pleased with this today! Design progress is in the finest details now for V4 board, and had a revelation last week about the temp sensing circuit - why use the stock system? It is old, and many are troublesome. So decided to include a temperature sensor on the board - this makes it much easier to setup Auto temp control if it is wanted. The only downside is the button with "AUTO" on it and the "Temperature" button are from Nissan Altimas, so one of those controls would need to be sourced to get just those buttons - those are not as common as the Sentra units.
So a quick list of the design features;
- Direct fit replacement for stock 928 control. Also able to fit in a custom situation with just a face housing change. Only the older Sentra ***** will work with the stock replacement fitup. The newer (larger with chrome trim ring) can be used in a custom setup, but won't fit in the space for a stock setup.
- Four fan speeds directly controlled from the unit, plus another single 20A relay for the rear blower if desired. The fresh air relay will work as original.
- Variable fan speed control is also built-in, just add a fan amplifier into the wiring to control the blower, and mount it in the airflow after the fan to dissipate heat. Same for the rear blower too - also built-in.
- User selectable Red or Blue button and background lighting, dimmable from either the stock rheostat, or Ed'd LED controller.
- Can control a variable electric water valve for those that want to control the heat input that way. Tested with Kysor electric water valve, good to -40C.
- Control the stock setting motor so the secondary functions also work as 928 original. Max AC turns off the water valve solenoid, and safety default can be configured for full open on the valve if the system fails.
- On-board temp sensor circuit means the old 928 sensors can be ignored, if Auto temp control is wanted. Just writing code for the Auto function will be a challenge.
- Three extra 1A relays are available for external functions (configurable as either NO or NC), plus a 12V/300mA transistor if faster control is required.
- A 10A relay with extra large traces on both sides of the board for the AC compressor circuit, under program control.
- A DAC output is available - 12bit, and 0 - 3.3V range, but very small current - good for signal out to an op-amp or voltage regulator.
- CANbus TX and RX are available on the board, but I will not be doing any programming for that - out of my league there!
- I'll probably add a tiny fan to the housing to draw air past the temp sensor.
- A MOD button will be part of the front board - I plan for this to act like a "SHIFT" key - when held down, the other 3 buttons and ***** can be operated and have different outputs or functions, all defined by programming.
That's it - a study in "scope creep" if there ever was one! I'm hoping this is flexible enough design for use in other cars that have the solenoid vacuum controls. Next is to order the V4 board, and a set of components for a test board assembly.
So a quick list of the design features;
- Direct fit replacement for stock 928 control. Also able to fit in a custom situation with just a face housing change. Only the older Sentra ***** will work with the stock replacement fitup. The newer (larger with chrome trim ring) can be used in a custom setup, but won't fit in the space for a stock setup.
- Four fan speeds directly controlled from the unit, plus another single 20A relay for the rear blower if desired. The fresh air relay will work as original.
- Variable fan speed control is also built-in, just add a fan amplifier into the wiring to control the blower, and mount it in the airflow after the fan to dissipate heat. Same for the rear blower too - also built-in.
- User selectable Red or Blue button and background lighting, dimmable from either the stock rheostat, or Ed'd LED controller.
- Can control a variable electric water valve for those that want to control the heat input that way. Tested with Kysor electric water valve, good to -40C.
- Control the stock setting motor so the secondary functions also work as 928 original. Max AC turns off the water valve solenoid, and safety default can be configured for full open on the valve if the system fails.
- On-board temp sensor circuit means the old 928 sensors can be ignored, if Auto temp control is wanted. Just writing code for the Auto function will be a challenge.
- Three extra 1A relays are available for external functions (configurable as either NO or NC), plus a 12V/300mA transistor if faster control is required.
- A 10A relay with extra large traces on both sides of the board for the AC compressor circuit, under program control.
- A DAC output is available - 12bit, and 0 - 3.3V range, but very small current - good for signal out to an op-amp or voltage regulator.
- CANbus TX and RX are available on the board, but I will not be doing any programming for that - out of my league there!
- I'll probably add a tiny fan to the housing to draw air past the temp sensor.
- A MOD button will be part of the front board - I plan for this to act like a "SHIFT" key - when held down, the other 3 buttons and ***** can be operated and have different outputs or functions, all defined by programming.
That's it - a study in "scope creep" if there ever was one! I'm hoping this is flexible enough design for use in other cars that have the solenoid vacuum controls. Next is to order the V4 board, and a set of components for a test board assembly.
My control head just went out in my 86 928. I was on the forum to look for options. What luck is this? A wizard in electronics is building a bigger better version of exactly what I need? I would like to add my name to the list of enthusiastic buyers.
10-01-2016, 11:10 PM
#189
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Join Date: Nov 2011
Location: Adelaide, South Australia
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The goal is plug and play for those that want to keep the stock functionality. It fits in the stock space and mounts the same. If you want to convert to infinite fan speed control, then a fan amplifier will need to be sourced and installed into the airflow after the fan, and an adapter harness will be needed for this option. I'm considering making those here (or sourcing them from a harness manufacturer).
An unknown at this time is the rear air system - specifically the temp control and how it works. I'll be digging into that next.
An unknown at this time is the rear air system - specifically the temp control and how it works. I'll be digging into that next.
what year Altima? There seems to be different ones.
Is the Kysor valve #3499010?
Mike
10-02-2016, 09:07 PM
#190
Pro
Thread Starter
Still moving forward on this project - a few speed bumps along the way since last post. Been working on the first V4 assemblies and developing my assembly test process to ensure parts are working correctly before moving on to next steps. Also redesigning the housing for this slightly longer board assembly and for better cost as a 3D printed part. I have the first V4 test assembly done, working on the code - turns out there is some fine tuning of the code that the hardware determines, not the other way around! The second V4 is in process of assembly, testing switches and LEDs before the ***** are installed. Speaking of *****, I figured out how to remove the center buttons from these without damage, and now have a set of ***** with the chrome ring with AUTO function and termperature settings on the center **** - these are for the second V4 assembly, and will go to a field test once the latest housings arrive in late Oct.
To answer Mike's questions, the fan amplifier I'm using so far is from a 2005 Nissan Altima with Auto temp control, though this is not totally proven in a high stress situation yet (slow fan speed with hot air going past). The water valve I have been testing with is a standard Kysor distributed actuator, with markings from "CEI" on the shell. The key is this valve has 4 pins, all together with no gaps on the pattern. I'll use 3 of these - power, GND, and reference voltage supplied by my unit.
Main challenge now is getting the code working smoothly so it has that "production car" feel - I'll keep at it!
To answer Mike's questions, the fan amplifier I'm using so far is from a 2005 Nissan Altima with Auto temp control, though this is not totally proven in a high stress situation yet (slow fan speed with hot air going past). The water valve I have been testing with is a standard Kysor distributed actuator, with markings from "CEI" on the shell. The key is this valve has 4 pins, all together with no gaps on the pattern. I'll use 3 of these - power, GND, and reference voltage supplied by my unit.
Main challenge now is getting the code working smoothly so it has that "production car" feel - I'll keep at it!
10-02-2016, 11:27 PM
#191
Rennlist Member
Oh you're killing me. I want this so bad to finish my interior rebuild
Last edited by jeff spahn; 10-15-2016 at 01:11 PM.
01-03-2017, 04:59 PM
#193
Racer
.
01-04-2017, 09:57 AM
#195
Pro
Thread Starter
Note - that hammer is dedicated to smashing the c**p out of any electronic project that doesn't go the way I want it to! Being my first project - the hammer is not used - yet. The project has slowed somewhat due to life's potholes (breast cancer we are dealing with), but still moving forward. I have the first field test unit assembled, just trying to get the fancier functions in the code working to match the Nissan operation I'm used to. This unit has been on my test board, running the variable speed fan controller, and electronic water valve controller at the same time. Last part of this test is to connect the on-board relays to the vacuum solenoids to prove those work - not worried though as that has worked in the past. The second assembly is 90% done, to go into my car for functional/installation testing. I'll keep my first test assembly as the "master sample" to be referred to and trial programming on as this progresses. The 4th assembly will also be a field test unit, probably for MY84+ to also check installation/functionality as direct replacement.
I have a minor redesign done on the boards (v5? now) to accommodate a couple obsolete items, better cooling fan housing fitup, and go to only white LEDs - the Blue/Red option seems like more hassle that it is worth, and not much interest in that capability. Still need to verify the stock rheostat will feed my Teensy chip correctly for dimming functions on the LEDs. I think this will work with Ed's LED dimmer if that is already installed, but still to be proven.
I know the question of $ cost is still hanging out there. So far component costs are $350-400USD (and that has been trimmed down considerably with design work), plus approx 8-9 hours of my assembly time, and 1-2 hours of testing and tuning per unit. My current estimate for final cost is $700-800USD per unit. I realize for that money this had better work perfectly and look like OEM! The first couple field units will be at a reduced cost, plus data feedback to me as part of the payment. This is completely hand assembled for now. If demand is enough, then I'll check into automated soldering services to hopefully cut down on cost, and free up some of my time.
I have a minor redesign done on the boards (v5? now) to accommodate a couple obsolete items, better cooling fan housing fitup, and go to only white LEDs - the Blue/Red option seems like more hassle that it is worth, and not much interest in that capability. Still need to verify the stock rheostat will feed my Teensy chip correctly for dimming functions on the LEDs. I think this will work with Ed's LED dimmer if that is already installed, but still to be proven.
I know the question of $ cost is still hanging out there. So far component costs are $350-400USD (and that has been trimmed down considerably with design work), plus approx 8-9 hours of my assembly time, and 1-2 hours of testing and tuning per unit. My current estimate for final cost is $700-800USD per unit. I realize for that money this had better work perfectly and look like OEM! The first couple field units will be at a reduced cost, plus data feedback to me as part of the payment. This is completely hand assembled for now. If demand is enough, then I'll check into automated soldering services to hopefully cut down on cost, and free up some of my time.