Hello to everyone that read this....
I have a idea that I'd like to bounce of someone that has more arduino-fu than me.
I've got this old Toyota Hilux that the previous owner gutted the controls for the cabin heater.
Only to things are left and thats the fanspeed control, and the hot/cold regulator (but that doesn't real work)
I have a background in R/C airplane and computers, so I was thinking that I could install some servos here and there.
And then have an arduino control all that " this button does that" and so on.
Any one care to start kicking me in the right direction?
I've started looking in to what needs to be controlled, and this is what I got as of now.
-Fanspeed switch, 5 positions (I`m thinking of using the OME switch, and having it manipulated by a servo/stepper)
-Temp hot/cold.
-Nozzle control, 6 positions (eg. floor, "in-yer-face",defrost, and so on...)
-Inside/outside air, on/off.
I thought Top Gear proved that a Hilux is unbreakable.
I was thinking of buying a used one a few years ago but they were too expensive. Based on what you say I'm glad I didn't.
More seriously, an Arduino could easily cope with a 5 position switch and a few relays.
Just be aware that an Arduino I/O pin can only supply about 20mA and that the maximum voltage on any pin cannot exceed 5v - assuming you are using a 5v Arduino rather than a 3.3v device.
Is the stuff for controlling the fan speed built into the heater (a series of resistors) or do you want to control the fan with a motor driver such as is used in model aircraft?
Does your background in RC and computers include any schematic reading/drawing experience ? Can you hand draw a schematic of everything you want to include in your project and take a photo of it and post it so we have something to reference ? Do you know exactly what the function of the fan 5-speed switch is ? Has it occurred to you that it might make for sense to get a relay bank module to select the speed reduction resistors for the fan ? Using a servo might be problematic from a mechanical standpoint and if you get counter chip you can select one of 5 outputs with addresses such that only one of the resistors can be connected at a time.
It is similar to a light chaser circuit only instead of sequencing lights , you are selecting a resistor. The chip can be replaced by a SW CASE statement that accomplishes the same function.
It is customary when posting for a project to include things like the parts list (which you have already started) and a schematic,
along with a SPECIFICATIONS table or list that lists the electrical specs, like voltage and current for each of the components.
It doesn't necessarily all have to be posted on the first post but there should be some intent from the beginning to work toward that objective.
raschemmel:
Has it occurred to you that it might make for sense to get a relay bank module to select the speed reduction resistors for the fan ? Using a servo might be problematic
Agreed, I would not use a servo to move the OEM switch. I'm also partial to relays myself, but the 5 positions are likely to be OFF, R1+R2, R1, R2, and no-resistor in a complicated connection scheme. I've never been a fan of the resistors, and personally would be much happier eliminating them and using MOSFETs to PWM the blower motor. It's just cleaner from an implementation standpoint and also gives you the option of letting the user select the fan speed with a pot, which allows for "infinite" fan speeds rather than four+off.
As for the other controls, you may find that the temperature and recirc flaps and each air outlet flap is controlled by a servo already. It's probably not a standard hobby servo, though. It may be a vacuum servo or some proprietary electrical-mechanical device that you may or may not be able to reverse engineer. It may be worth investigating using the ones already there (in the case of vacuum servos, the Arduino can control vacuum solenoids to operate them).
Finally, just to throw gas on the fire, you can add digital temperature and humidity sensors and automatically adjust the fan speed and automatically turn on the defroster and things.
You culd use an input to set a temparature, and then use a PID function to maintain that temperature with the help of the servos and a temparute sensor. Just like a modern cliamate control unit in newer cars. =)
Wow, thanks for all the feedback.
I had some spare time to day, and had look at the fan switch.
It was just a basic selector switch, with the resistors located elsewhere.
So that is easily replaced by four relays.
Might go down the MOSFET road later on, keeping it KISS for now.
I also got time to make a Logic function diagram for this project, for now it just basic functions.
All the valves are manual operated cable, so I guess stepper motors is in order....
The resirk. valve flapper is just an on/off deal, so I guess a solenoid can be utilized for that function.
The next step will be to measure the throw of the main valve selector cable, and look into maybe modify it.
tylernt:
Finally, just to throw gas on the fire, you can add digital temperature and humidity sensors and automatically adjust the fan speed and automatically turn on the defroster and things.
Yes I know, as soon as the basic setup is running thats one of the things I`ll look into.That and incorporate the diesel aux heater some how.
Robin2:
I thought Top Gear proved that a Hilux is unbreakable.
I was thinking of buying a used one a few years ago but they were too expensive. Based on what you say I'm glad I didn't.
HIlux`s are hard to kill for sure. The previous owner of my car, apparently try to kill it by letting a rabid dog eat the inside of it.
The dog had something against the heater panels. (and seats for that matter).
I just love that I can wipe up my toolkit fix almost anything with a blow of an good sized hammer.(except for heater panels).
I have some more on components and stuff later..
Keep floating idea, suggestions...
Insanety:
All the valves are manual operated cable, so I guess stepper motors is in order....
Servos are SOOOO much easier to use than stepper motors ..
They are easier to install,
easier to control with an Arduino because the driver circuitry is included within the servo
designed to have absolute position control - whereas a stepper will need limit switches
and probably cheaper when the cost of driver boards for steppers and all the ancillary stuff is taken into account
You can get some very high torque servos, if necessary.
