Which PIC microcontroller to use...?

[salman.]

Hi,

I am advised to use PIC micro controller for a Project that monitors methane gas and Carbon mono-oxide in homes. I need help in choosing the right PIC micro-controller for the project.

I need to accomplish the following tasks using the MCU :

1- Monitor Gas sensors (3 - 4 sensors)
2- run bar graph displays
3- run an LCD
4- run a stepper motor
5- turn on/off alarms
6- turn on/off exhaust fans

please guide me on which PIC MCU to use for these tasks,

Thanking you guys in anticipation.
Salman

 

[horace1]

do you intend to use a development board or design and build a PCB yourself?

for development boards Microchip's microsticks are low cost (about £20 for the Microstick I)
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however, I doubt if these boards would have sufficient I/O pins to support all the peripherals you have specified
In that case the Explorer 16 (approx cost £130) would be a good choice
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it comes PIC24FJ128GA010 and the dsPIC33FJ256GP710 PIMs, an LCD and plenty of spare I/O pins.
There is also a range of Pictail plus modules you can plug into board
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including a prototype board for your own circuits.

I think you need to list the I/O facilities you require, e.g. Digital IO, analogue IO, I2C, SPI, etc
You can then use a product selection tool
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[electronicsbasecom]

Hello,

Since we recently did project with gas sensors, we recommend dsPIC30F4013 because this controller has everything you need: 12 ADC, plenty of I/O pins, 2 UARTS, SPI etc... Here you can find more info about dsPIC30F4013: http://www.electronics-base.com/index.php/dspic-tutorials

Working with this uC is not difficult but performance are quite splendid. I don't have much info about your peoject but I will notice you the main problems in our case.
Gas sensors, the cheap ones can consume a lot of current for heating, so our advice is to make logig for separate control of every sensor. This is usefull if you wanna make battery supplied device. Here is sensor board:


If you have any question don't esitate ti contact us.

 

[salman.]

do you intend to use a development board or design and build a PCB yourself?

for development boards Microchip's microsticks are low cost (about £20 for the Microstick I)
**broken link removed**

however, I doubt if these boards would have sufficient I/O pins to support all the peripherals you have specified
In that case the Explorer 16 (approx cost £130) would be a good choice
**broken link removed**

it comes PIC24FJ128GA010 and the dsPIC33FJ256GP710 PIMs, an LCD and plenty of spare I/O pins.
There is also a range of Pictail plus modules you can plug into board
**broken link removed**

including a prototype board for your own circuits.

I think you need to list the I/O facilities you require, e.g. Digital IO, analogue IO, I2C, SPI, etc
You can then use a product selection tool
**broken link removed**

thank you for your response,
horace1, I intend to design and build my own PCB and I need Both Analog I/O and Digital I/O

- - - Updated - - -

Hello,

Since we recently did project with gas sensors, we recommend dsPIC30F4013 because this controller has everything you need: 12 ADC, plenty of I/O pins, 2 UARTS, SPI etc... Here you can find more info about dsPIC30F4013: http://www.electronics-base.com/index.php/dspic-tutorials

Working with this uC is not difficult but performance are quite splendid. I don't have much info about your peoject but I will notice you the main problems in our case.
Gas sensors, the cheap ones can consume a lot of current for heating, so our advice is to make logig for separate control of every sensor. This is usefull if you wanna make battery supplied device. Here is sensor board:


If you have any question don't esitate ti contact us.

Thank you for the response and info. electronicsbasecom,

I intend to build this project keeping the cost minimum, so here is what i intend to do........I want to use methane(CH4) Gas sensors and CO(carbon mono-oxide) gas sensors
:
http://docs.google.com/viewer?a=v&q=cache:C9d69WsOhr8Jrobots.co.in/Datasheets/MQ4.pdf+methane+gas+sensor+MQ+4&hl=en&gl=pk&pid=bl&srcid=ADGEESgXm6HMmCDXGmP7zFnGd-CR8iLUIzeL4O81RQGQgYXwZDpUpge4kVE5729b0uDuXBXbDH2EYch-SD-r0SJH5PsXHfRElcK6gpWHrzWglPLICJJrhgYhDD3EGZMRBCzEofIq8iy4&sig=AHIEtbTgegN_b2LQ0TZfeh2rXrqtm-jdXw&pli=1[/URL]

-1- I want to use this sensor to monitor methane(CH4) gas level near the stove and in other rooms(2) where there are gas heaters installed (the place i am from, people use gas heaters in their rooms when its cold) so that if there's a gas leakage the µcontroller sounds an alarm and shuts off the house's main gas valve via a stepper motor.

-2- I also want to monitor CO(carbon mono-oxide) levels in the rooms(2) so if they get high the µcontroller switches on the respective room's exhaust fan and switches it back off when the CO levels are back to normal.

-3- I need the bar graph displays to display the CH4 and CO gas levels at all times, I need the LCD display to display the status of the whole thing.

Please tell me whats the advantage of using DSPIC over the other series of PIC in this project? ..like PIC16F, PIC18F..etc

 

[electronicsbasecom]

The DSPic is a much more advance controller chip than a regular PIC. You can do serius math which you may need since responses of gas sensors are often logaritmic. Peripherals are better and faster, auto multiplexing for reading a chain of inputs with a single read, motor control stuff, low latency flash read, linear memory space and so on.

 

[horace1]

I agree with the comments of electronicsbasecom

Unless working on products that will run into 10000's of units (where the odd few pence cost many be critical) I would not consider PIC16s or PIC18s.
The functionality, power, IO, etc of PIC24s/dsPICs/PIC32s simplifies system development and implementation making the small extra cost worth while. In particular the DSP libraries for the dsPIC are very useful
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Also one often finds that system requirements expand with time and spare IO pins come in useful. For example, we have a legacy PIC18F97J60 based system that now has so much extra IO via SPI and I2C modules that we are looking to replace it with a PIC32.

 

[salman.]

horace1 and electronicsbasecom thank you both for helping me, I really appreciate it !

You guys are right, I should use a DSPIC.

 

[willis...]

I would definitely recommend one of the dsPICs. While they have a plethora of IOs and sensor capabilities, most of them also come with a dedicated PWM module, making stepper motor control a breeze.

Regards,
Willis