271zmeihc

My project I'm going to make was the Multichannel Data Logger. It is a Data Logger which can log more than 1 variable (ie. Temperature, Humidity, Light) which can be used for data logging a room or car, thus making it as portable as possible. I'm planning on using the PIC16F887 since it has more than 1 input pin, serial pic-to-pc pin and anolog-to-digital converter. The recorded data should be sent to PC using USB interface and can be viewed on spreadsheet (ie. Excel).

I would like to receive some comments on it and guide if possible but making it original product from my creation. Thanks

ericgibbs

hi,
The memory storage capacity of the F887 is limited, depends how much data you want to save before you download to the PC.

The F877 does not have USB, you would have to program the F877 in whats called 'bit banging', thats a stupid term for 'bit switching'

What environmental sensors are you planning to use.?

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Eric
"Good enough is Perfect"

PIC tutorials:
Nigel's: www.winpicprog.co.uk/
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

petrv

Hi,
if you need USB why not use a MCU with USB, like e.g. PIC18F4550 ?

271zmeihc

I'm planning on adding temperature sensor, humidity sensor and light sensor. I will start with 3 sensors first. These 3 variables will be log, then transfer to PC and reset every 24 hours.

I would like to try another PIC. But I'm not sure if there are PIC with more than 1 input pins with Analog-to-Digital Convertor like 16F877. I wonder if I could convert the serial transfer to USB? Is there Serial to USB convertor?

petrv

Yes there are such chips like serial to USB. But it does not make sense to use it with a PIC when you can use a PIC with USB, why waste money on another IC and not exactly cheap ? Get the datasheet from www.microchip.com for PIC18F4550. It has even more analog pins with ADC then your PIC (13).

271zmeihc

Thanks a lot for your recommendation. I have download datasheet on the pic you recommended me and i found it does make sense to use it instead of my pic. The bad thing is I have bought the 16F877.

petrv

So buy a PIC18F4550 and you can save your 16F877 for a different project both MCUs are quite popular and useful for many designs.

271zmeihc

I have another question regarding sensors IC that I am going to use. I'm using temperature, light and humidity sensor ICs. Do I need extra components such capacitor or resistors to support these sensors ICs? Or the ICs are already all in one sensors and transducer?

ericgibbs

hi,
You will have to tell us which sensor ic's you are going to use before that question can be answered.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Nigel's: www.winpicprog.co.uk/
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

Pommie

I would advice against trying to use the 4550 with USB. Unless you are an experienced C programmer with knowledge of USB, you will fail miserably. Best stick with your 16F887 and use a serial to USB adapter. The 887 has 8K of ROM space that can be used to store data. You could easily use half for storing your data and if you are only writing to it once per day then the flash will eventually "wear out" in 274 years. How many samples per day are you considering? If you need more storage then a 1Meg EEPROM is easy to interface.

If you are comfortable with C you might consider switching to a 18 series pic and use the free C18 compiler. You also get the advantage of a lot more memory.

Mike.

271zmeihc

Thanks. I was planning to used the 877 because I was required to use this PIC for this project. I'm learning on using C programming through a 10 days-3 hours short course to program the PIC. I would like to have some links for tutorial or tips on programming PIC via C programming.

Here's the IC sensor I'm using:
Temperature - LM35
Humidity - HS1100
Light - LX1970-2

Do I need a separate real-time clock IC for the logger?

bryan1

As this sounds like a school project then for a RTC go take a look at a pic app note on using timer1 and a watch crystal and has been suggested above the 24aa1034 eeprom has 1 meg of storage and you can daisy chain 4 of them together. so go do some research mate and i'm sure you'll get there .

Cheers Bryan

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