how to connect my A.C. with my laptop which programming language i should use???
Posted 29 March 2012 - 02:21 AM
i have one question
how to program non-computer device with my laptop..
if i want to program my Air Condition timing and if i want to make any change in circuit board of my A.C. than which programming language should i use...???
one of my friend told me that i have a knowledge of COBOL language.. is it true???
please help me friends...
Posted 29 March 2012 - 11:26 AM
Posted 02 April 2012 - 06:55 PM
Posted 02 April 2012 - 08:57 PM
Not likely. Virtually all small-ish microcontrollers use onboard flash these days (others mainly use external NAND flash). The days of external ROMs are long over (last I've seen it was in 8051-based hardware from 10+ years ago where the code was too big to fit in flash at the time). Using a ROM chip would add unnecessary cost and complexity. It's not supported by most modern MCUs either (I'm really glad those days are over)
It could be C, but something so simple and produced with such a high volume could be written in assembly as well (it saves a bit of flash, which saves a tiny amount of money on the MCU, which adds up nicely at this volume of sales). Using cobol here would make no sense. I've never seen or heard of a MCU programmed in cobol and it's not exactly popular for new projects on the PC side either (it seems to be mainly used on mainframes today).
...if you want to reverse-engineer the original firmware, yes. But that would take forever (even if you're used to read disassembled code e.g. figuring out where/how it drives the multiplexed 7 segment displays or interprets the IR pulses from the remote). And it won't be x86 assembly either (it might even be something no disassembler supports, including IDA Pro), and large parts of it will be specific to particular MCU they used (e.g. how GPIO pin directions are set, registers for clock prescaling, watch dog timers and so on). You'd also need to figure out what goes to which pin. Nevermind that it's almost certain that the flash is protected/secured anyway so it's most likely not an option in the first place.
That's highly unlikely. I'd expect to find chips from many other MCU lines well before that.
Either ways, it would be quicker to build a new controller from scratch and it's most likely your only option too. You'll have to figure out:
-how to drive the compressor, condenser fan and evaporator's blower (using a relay, triac, etc)
-the fan (blower) speeds might be done via PWM or multiple windings on the motor
-how to read the existing temp sensors or otherwise substitute your own, and the pressure sensors too if there are any
-ideally interface with the existing buttons and also reuse the 7 segment displays (otherwise redo it all from scratch) if you want to preserve its look
-reuse the IR sensor for the remote or add your own (you'll have to record/analyze the codes sent by the remote yourself as well, in order to write code to interpret it later)
-add anything else you might want as an extra (like for communicating with your PC)
-create a new schematic for your new circuit then route the PCB (or use a proto board), repeat as necessary to fix design mistakes (create new prototypes)
-using a pre-made board (like puntoMX already said) is a bit quicker, but it's not very well adapted to the task (e.g. the one linked to buy puntoMX can't read the necessary sensors -- there are plenty of others though. Lots of hobbyists would chose an arduino board for this kind of stuff)
-write the code to drive the multiplexed 7 segment displays (or control a hd44780 LCD controller if you prefer), write the code to decode the infrared pulses from the remote control and so on
-ideally you want the temperature to be controlled with a PID controller (have fun tuning it by changing the constants)
-you have to recreate all the cycle types (standard, energy saver, etc) you want by yourself
-you may need to calibrate your temperature sensors for better accuracy (a lot of popular sensors can have an offset of a couple degrees Celsius in either direction)
-if you want to control it with your PC then you have to write that software as well i.e. design some communication protocol to make both exchange data, then write the code to make it work for both the MCU and your PC
It's several weeks or a few months of full-time work for someone who *really* knows what he's doing. And knowing what you're doing is not optional here. You need to be pretty good at writing code in C for the microcontroller (this better not be your first project in C!). Same thing for the program you want to run on your PC if you want it to do anything interesting (communication, intelligent control, graphing, data logging, etc). It all has to be very stable too. You're also playing with mains voltage so beware (risks of electrocution, fire, etc). Also, when working in such equipment (rewiring stuff) you have to be careful not to damage refrigerant lines. This is definitely not a project for beginners.
I could help (I've worked on a couple HVAC controller designs) but it looks like you lack a lot of expertise to make this happen on your own.
Posted 04 April 2012 - 09:01 PM
Posted 04 April 2012 - 10:03 PM
It's just a commenting style. It's easier to follow this way (IMO) than a long winded reply without clearly seeing what one is replying to. In other words, it's meant to put things in context.
Sometimes it's hard to sense sarcasm and such things by reading plain old text (no smilies or anything either). I thought you were totally serious. I've seen plenty of people who would say things like that and even weirder things (it's the internet, weird people aren't exactly uncommon), even on this forum. If I read it again it now makes sense, especially if you insert a period after "variant".
Not to say they are not used or that you don't know what you're saying but I have yet to come across one. Since were talking about cheap window units specifically I'll provide one example: LG/Goldstar uses Samsung's SAM87RC series MCUs (for example the C8475).
OTP? Absolutely. But EPROM on a modern MCU i.e. a windowed part? We must have different definitions of modern then. Unless you meant EEPROM which is quite something else and not a separate ROM chip like you were talking about in your first post.
That wasn't the intent and I'm sincerely sorry if it made you feel that way. Also, the moderator status doesn't really make one all that special, it mostly means we waste time deleting spam or warez posts on a daily basis.