Datalogger/acquisition

[alamy]

Hi..

i'm thinking to develop data logger /acquisition project...

just to get initial idea to develop all this thing...

what should i have ?...
maybe...PIC, memory, software(pc)..what else?

and for the pic...what kind of pic suited to this project.what is the features?..USARt, i2c?...

i've looked to the pic16f88..adc, usart,i2c...what do you think..?

memory...24LC515 ----515k..?

then how do i calculate...the period of my datalogger that record the data for interval 1s with 3 channels.

for software ...what is the best?..i just know a little on VB...

is there any website for references...or project to refer..

thanks in advance..

 

[bmcculla]

Silicon Labs has a cool 8051 with 2 16 bit 1MS/s AtoDs. It can DMA the data into external RAM. You just sample until the memory is full and then read the memory back through the serial port. The only down side is the part is a bit pricey (though not bad for what you get) and only comes in surface mount.

VB is the easiest language to work with for the serial port.

 

[plot]

How much memory are you going to need on the chip? Figure that out first.

In other words, how many data sets will be logged and how many bits will each dataset be?

 

[Nigel Goodwin]

The classic PIC used in data loggers is the 16F877, which is a 40 pin PIC, this easily gives you up to 8 analogue input channels, connections for I2C EEPROM, a serial port, and an LCD display, plus spare I/O for buttons and switches.

But depending on your exact requirements a smaller PIC may be fine, any with A2D is all you need, and enough pins for what you want - there's no need for a PIC with hardware I2C, it's easily done in software.

My PIC tutorials include almost everything you need!.

I presume the EEPROM you mentioned is a 24LC512 (not a 515), giving 512 kbits of storage. You can use multiples of them to increase capacity.

For the period you simply wait 1 second, do the three samples, then wait again - it's probably best to use a timer interrupt for that!.

 

[alamy]

For the period you simply wait 1 second, do the three samples, then wait again - it's probably best to use a timer interrupt for that!.

i'm sorry, maybe i do not state clearly (poor english)..

what i mean is...how long my datalogger can record the data (3 channel) if my memory is 512k..(an hour, a day or a week?)..then how do i calculate?...

your tutorial help me a lot on understanding programming PIC..i not explore yet your tutorial on EEPROM...

i'm still looking to the software (such as VB) that can communicate with PIC...any project related ?..

thanks in advance..

 

[Nigel Goodwin]

what i mean is...how long my datalogger can record the data (3 channel) if my memory is 512k..(an hour, a day or a week?)..then how do i calculate?...

It's simple maths, your EEPROM has 524288 bits, so if you're storing three 8 bit samples, simply divide 524288 by 24 to give 21845 seconds. This works out to about 6 hours.