Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Design Program for a 8051 Digital Temperature Controller

Status
Not open for further replies.

dav456

Junior Member level 3
Joined
Apr 22, 2016
Messages
26
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
211
12271128_1711635182399684_271678944_o.jpg

The circuit uses a
1.LM35 temperature sensor
2.AT89C51 microcontroller
3. 2 CD4511 BCD to HEX
4. 2 7 SEG disp
5. a relay connected to a lamp
6.ADC0804

The LM35 is connected to the ADC.
I want to set a temperature say 40 degrees celcius

The microcontroller will read the temperature from lm 35 and display it in the 7 segment display.

If the temperature is less than the set temperature
the lamp will glow else not.

How do I go about this program.

Does having a capacitor infront of CS pin of ADC0804 ensure it is always 0 instead of connecting it to 8051 and programming it to be 0?
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
19,940
Helped
4,370
Reputation
8,749
Reaction score
4,347
Trophy points
1,393
Activity points
131,994
Hi,

Some issues:
* Why the pull-up resistors at P0x?
* Why do you use the 7407?
* you should use a 100n X7R capacitor at EACH IC VCC pin with short connection to GND plane.
* your 7805 will becom very hot. You need a heatsink. Or use a transformer with lower secondary voltage.
* Why two transistors to drive a relay?

Klaus
 

dav456

Junior Member level 3
Joined
Apr 22, 2016
Messages
26
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
211
Hi,

Some issues:
* Why the pull-up resistors at P0x?
* Why do you use the 7407?
* you should use a 100n X7R capacitor at EACH IC VCC pin with short connection to GND plane.
* your 7805 will becom very hot. You need a heatsink. Or use a transformer with lower secondary voltage.
* Why two transistors to drive a relay?

Klaus

I have not used 7407 in real circuit

I read P0 of 8051 is open drain hence we have to use pull up register

I have used heatsink
 

andre_teprom

Super Moderator
Staff member
Joined
Nov 7, 2006
Messages
9,274
Helped
1,156
Reputation
2,331
Reaction score
1,144
Trophy points
1,403
Location
Brazil
Activity points
54,008
Why two transistors to drive a relay?

In addition to Klaus remark, from where comes the voltage V_raw applied to relay bobin ?
If you did that to provide some impedance to 5V, it's ok, otherwise uC will be susceptible to reset.
 

dav456

Junior Member level 3
Joined
Apr 22, 2016
Messages
26
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
211
In addition to Klaus remark, from where comes the voltage V_raw applied to relay bobin ?
If you did that to provide some impedance to 5V, it's ok, otherwise uC will be susceptible to reset.

I dont know if it works with v raw or 2 transistors or not till I simulate the circuit,which is why I need the program.
My first priority is to read the temperature and display it.
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
19,940
Helped
4,370
Reputation
8,749
Reaction score
4,347
Trophy points
1,393
Activity points
131,994
Hi,

without knowing what V_raw is and without the relay specifications nobody can guarantee the function.
Even the simulation won´t tell you if it works or not.

Do you want us to guess?

Klaus
 

andre_teprom

Super Moderator
Staff member
Joined
Nov 7, 2006
Messages
9,274
Helped
1,156
Reputation
2,331
Reaction score
1,144
Trophy points
1,403
Location
Brazil
Activity points
54,008
I dont know if it works with v raw or 2 transistors or not till I simulate the circuit,which is why I need the program. My first priority is to read the temperature and display it.
So, the additional working circuitry's description you gave is purposeless for the current demand.
Did you make a search on this forum using keyword criteria “8051+LM35+ ADC0804” ? I found many occurrences.
 

dav456

Junior Member level 3
Joined
Apr 22, 2016
Messages
26
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
211
So, the additional working circuitry's description you gave is purposeless for the current demand.
Did you make a search on this forum using keyword criteria “8051+LM35+ ADC0804” ?

I did google a lot but none of them use cd4511 and 2 7 segment

I can fix the transistor part later but what I care more is the port that drives the relay is working or not.

The rest of the circuit is pretty much fixed.
I need the program.

- - - Updated - - -

Hi,

without knowing what V_raw is and without the relay specifications nobody can guarantee the function.
Even the simulation won´t tell you if it works or not.

Do you want us to guess?

Klaus

vraw is the voltage before 7805
For now as long as the port that drives the relay is working as per program and the the temperature is properly displayed it is ok.

I can see in the simulation if the port is high or low.
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
19,940
Helped
4,370
Reputation
8,749
Reaction score
4,347
Trophy points
1,393
Activity points
131,994
Hi,

You know: I = U / R.

I wonder how you say your calculator to divide "the voltage before 7805" by "the resistance of the relay".

Klaus
 

andre_teprom

Super Moderator
Staff member
Joined
Nov 7, 2006
Messages
9,274
Helped
1,156
Reputation
2,331
Reaction score
1,144
Trophy points
1,403
Location
Brazil
Activity points
54,008
The rest of the circuit is pretty much fixed.
I need the program

I can't believe that you have not found any usable code either at Google or at , with which you could start your own project. Please tell me that you're not expecting that someone give you the whole working code for specifications you stated at post #1.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top