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Mini project, need some advice.

AnthonyNg01

Oct 24, 2017
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Alarm clock with a lots of features.
An alarm clock that display day of the Week(days), Calendar(date), Time, Humidity & Temperature.
Ultra low power if possible.
i m new at this.
i plan to use PIC for my project, i m not sure which PIC can fulfill the requirement, and i need advice on what component should i use?
Component:
PIC16F84A
DHT22
M41T62
Piezo Buzzer
LCD
Is DHT22, M41T62 a good choice ? any extra component needed ?
 

BobK

Jan 5, 2010
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Basically, any but the very smallest PICs could do this.

To choose one, list all the inputs and outputs that you need. Add a few extras just in case, and start looking at PICs with that many I/O pins or more.

The PIC16F84A is a very old obsolete PIC. You can get many more features with newer ones for less money. It has 18 pins, 16 I/O pins. You probably want to dedicate 2 for programming and debugging, so that would leave 14 I/O, with one of them being only input.

A more modern version of a PIC this size would be the PIC16F1847.

Do not use the 20 pin PICs. They need a special chip for debugging. If the 18 pin is not enough, go for a 28 pin one.

Bob
 

kellys_eye

Jun 25, 2010
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Consider an Arduino since those peripheral devices already have many sketches (libraries) written for them.
 

AnthonyNg01

Oct 24, 2017
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Oct 24, 2017
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Basically, any but the very smallest PICs could do this.

To choose one, list all the inputs and outputs that you need. Add a few extras just in case, and start looking at PICs with that many I/O pins or more.

The PIC16F84A is a very old obsolete PIC. You can get many more features with newer ones for less money. It has 18 pins, 16 I/O pins. You probably want to dedicate 2 for programming and debugging, so that would leave 14 I/O, with one of them being only input.

A more modern version of a PIC this size would be the PIC16F1847.

Do not use the 20 pin PICs. They need a special chip for debugging. If the 18 pin is not enough, go for a 28 pin one.

Bob
Thanks Bob,

i look up the net, this is the closest to what i plan to build, and it seems like i need at least more than 24 I/O pin.
Will one PIC16F877A be sufficient to replace both microcontroller and the ADC converter?
source:https://www.engineersgarage.com/mic...lock-with-digital-thermometer-AT89C51-circuit
 

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kellys_eye

Jun 25, 2010
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You can get all the sensor AND display devices in an I2C 'flavour' these days so in theory only require TWO I/O lines....
 

BobK

Jan 5, 2010
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I really doubt that you need 24 pins.

The project you are looking at uses and external ADC to read an analog temperature sensor. the DHT22 does not use an analog interface, and, even if it did, the PIC has the ADC built in, so that is 8 pins you do not need.

The LCD can be run with 6 pins instead of the 11 that circuit is using, so that is 5 more pins you do not need.

You don't need a real time clock. Equip the PIC with a crystal and it can do that in software.

Here is my count:

Crystal 2 pins
LCD 6 pins
DHT22 1 pin
Buzzer 1 pin
Buttons 3 pins or more depending on what interface you want for setting it.

So, I think 13 pins is enough. Your original choice of an 18 pin PIC seems right.

Bob
 
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