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Mehtab AliParticipant
you can use either timer0 or timer1 for counting purpose.
Mehtab AliParticipantThe timers, timer0 and timer1 in 8051 can be used for counting the pulses fed into microcontroller. you initialize the microcontroller’s timer in the counter mode and fed pulses into it to be counted.
regards
Mehtab AliParticipantthis circuit is simply a switch. when the sensor senses the ir radiations it sends a current to the base of microcontroller, thus turning the transistor on and hence
their is zero volts at the ‘o/p to 8051’ pin. similarly when their is no current coming from the sensor then the transistor is off and the o/p is high at 5v.
The 10k resistor is choosen in such a way to keep the transistor in the saturation region if a current is applied at the base i-e Vce<0.7v.
because for transistor to be operated as a switch, it should be operated in cutoff and saturation region.
The other resistor is used for proper biasing of transistor.
Mehtab AliParticipantthis circuit is simply a switch. when the sensor senses the ir radiations it sends a current to the base of microcontroller, thus turning the transistor on and hence
their is zero volts at the ‘o/p to 8051’ pin. similarly when their is no current coming from the sensor then the transistor is off and the o/p is high at 5v.
The 10k resistor is choosen in such a way to keep the transistor in the saturation region if a current is applied at the base i-e Vce<0.7v.
because for transistor to be operated as a switch, it should be operated in cutoff and saturation region.
The other resistor is used for proper biasing of transistor.
April 24, 2012 at 4:43 pm in reply to: How to Load program on 89c51 using only tx/rx of rs232 .? help and give software to load file. #7537Mehtab AliParticipantread the circuits of gsm interfacing with microcontroller.
April 20, 2012 at 12:47 am in reply to: JH162A LCD initialise problem with at89s52: Showing black box #7513Mehtab AliParticipantlcd requires some time to execute the commands so after a command we need to either give it a delay or we can check the busy flag.the crystal frequency is ok. in your program delay(250) is appropriate for lcd.
i have run the c code and assembly code for lcd, and both displays data on lcd. you also check your connections.
April 19, 2012 at 5:03 pm in reply to: JH162A LCD initialise problem with at89s52: Showing black box #7509Mehtab AliParticipantyou try it using clear command and increase the delay as well. also you need to shift the cursor to right.
April 19, 2012 at 5:00 pm in reply to: JH162A LCD initialise problem with at89s52: Showing black box #7507Mehtab AliParticipantincrease the delay from ” delay(50) to delay(250)”
April 19, 2012 at 4:58 pm in reply to: JH162A LCD initialise problem with at89s52: Showing black box #7506Mehtab AliParticipantyou havent cleared lcd. it has previous data stored in it sometimes. please clear it by sending it 01 like ” lcdcmd(0x01);” also use a command “lcdcmd(0x06);” to shift the cursor to right.
Mehtab AliParticipanthave you made the circuit or not. if yes then post it here
Mehtab AliParticipantthere is a lot of material on internet about sar adc but i will send you some, that i found helpful.
Mehtab AliParticipantas i haven’t used sar adc, so i might not help in this regard.
Mehtab AliParticipanti suggest you to use ADC 0848. it has eight multiplexed channels through which it recieves analog signal so you can connect both your lm 35 and ldr sensors by selecting an appropriate step size.
adc0804 has only one input so you can give it input from either lm35 or ldr. also you must note that the output of adc0804 is an 8 bit parallel. then how can you send 16 bits
Mehtab AliParticipantwhich temperature sensor are you using and for what application
Mehtab AliParticipantmay be your lcd have some problem, you try another lcd also if you can post your program so that i can check if there some problem in that
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