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temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 13 Feb 2010 05:55
by delifadzli
hi everyone,,
i want to ask for a guidance for my project . The project basically use Temperature sensor (LM35) as input , PIC as "analyze" item and ac motor (output-speed change)..
here the problem is regarding 2 things
1. ADC problem-- LM35 interface pic
-either use PWM or sampling
2.the big one- how to interface PIC 16f877 and ac motor--can provide some code or diagramm..just for the guidance..
to be truth... i quite new in this area (microcontroller)....someone please...
wait for ur respond....
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 14 Feb 2010 22:01
by dariush_abbasi
Hi,
I don't know whether helps or not but...
There is a sample code for PIC and LM35 in the book called "ADVANCED PIC MICROCONTROLLER PROJECTS IN C".
I think that would be a good start.
Be successful.
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 15 Feb 2010 04:56
by delifadzli
thanks for the info..really hope it function well for the project...
by the way, how about the interface with ac induction motor.. isn't been conclude in the book??
i hope for Ur opinion about that...
waiting for respond....
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 15 Feb 2010 08:49
by dariush_abbasi
Hi,
No,not about motor,just for LM35 but the good point is the program is for Mikroc.
Be successful.
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 23 Feb 2010 17:26
by delifadzli
i am really blur and confused right know...can anyone tell me on how to interface the PIC16f877 with ac induction motor ( speed)...--ceiling fan...
guide me please....
urgent...
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 23 Feb 2010 18:33
by Radu86
I don't know for sure, but I think one way to control the speed of the motor is to use the PIC as a frequency converter. That means you have to recreate the sinusoidal voltage at different frequencies. As for this I do not have any code nor I have any idea where you could find something to help you.
Is the ac motor a 3 phase motor? If by construction it gives you access at the rotor's coils you can change the speed by adding resistors like in this link:
http://em.ucv.ro/elee/ro/realisations/m ... igure6.jpg
If it is not a 3 phase motor (you say it is a fan motor) than i guess the first part is the way to go.
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 23 Feb 2010 18:49
by delifadzli
thanks for the reply
eventually, this project used the ceiling fan motor-single phase motor...
can u suggest something...?
totally need help...
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 24 Feb 2010 10:43
by Radu86
I've done a little reading and I have an idea. These motors can be controlled through variable voltage and fixed frequency or fixed voltage variable frequency.
I think it is easier to variate the voltage. You can use the PIC as a chopper. I believe the technique is called PWM-Pulse With Modulation. Of course you will need other components in order to support the motor's current and voltage. I haven't tried this yet so I don't really now how it works or if it works, but in theory does
. The idea is to give pulses to a switch (relay transistor or anything that can act like a switch) in order to control an analog device (your motor in this case). the pulse is given by setting a pin to 1 and 0 at a chosen time rate. if you want these pulses to be faster you simply choose a shorter time rate.
create a few procedures and test them until you get the pulsing time you want.
For how to connect this to the motor I think there are a lot of methods on the internet.
Here:
http://www.freescale.com/files/microcon ... AN3471.pdf is a solution using PWM for a ceiling fan.
Hope it helps.
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 27 Mar 2010 17:48
by jennyfan
The LM35 could give more output power or voltage in your ceiling fan motor. Anyway, it should be better that the thermocouples.
Re: temperature sensor (LM35) + PIC16f877 + ac motor
Posted: 23 Oct 2010 09:43
by cath_3105
Our neighbor are doing electric fan repair. I heard that they also use LM35. As they said, LM35 gives more output voltage. It is the same with jennyfan.