Simple Data Logger

[TYKE]

Hi all
for my first project I want to build a PICAXE 08M module that will stop my 84ah leisure battery from deep discharging when it is connected to my cooler box. I am fairly happy with the coding side and the hardware but as a side line I was wondering if the eeprom on the chip could be used as a simple data logger? Can I take a sample say every hour place the result in the eeprom and read the results later?

 

[hippy]

Welcome to the PICAXE forum.

Data Eeprom can be used that way, but you are limited to the amount of Data Eeprom which is available after you have downloaded program code. If you try to use too much Data Eeprom you may end up corrupting your code. The best way to reserve space for data logging is to add to your program ...

Eeprom ( 0,0,0,0, 0,0,0,0 )

This will reserve 8 bytes of data logger storage which can be accessed by READ <adr> and WRITE <adr>, where <adr> can range between 0 and 7. You can reserve more or less bytes this way and the compiler will indicate if you are trying to use more data space than is available.

Note that there's only 256 bytes which are shared between code and data on the 08M. For more extensive data logging you will be better off with a larger PICAXE or larger PICAXE and using external I2C Eeprom.

 

[TYKE]

Thanks for the welcome and information Hippy

The amount of information captured isnt really important it was just to give me an indication of what was going on and to give me experience of working with the picaxe.

 

[TYKE]

How do you look at data collected on the eeprom? I've searched and read as much as I can but I cant find out.

 

[BeanieBots]

Basic manual 2 page 147. "Read" command, as mentioned by Hippy in post #2.

 

[TYKE]

Hi I didn’t explain myself properly, what I would like to do is look at the eeprom data on my pc so I could use it in a graph.

 

[BeanieBots]

Read the EEPROM then send to the PC using either Serout or Sertxd commands.
Terminal will display the values.
If you want to show as a graph then you will need some software on your PC to do that. Several packages available. "Selmadaq" is available free. It puts your data into a spreedsheet from which you could produce a graph.