Counter/datalogger

[SteveyD]

Hello again

I would like to try a new micro controller project using an LCD display or a 7seg LED will work as well.

1. Counter - using a micro switch to provide the input/trigger.
2. LED to indicate an input/trigger just occurred.
3. Total count displayed on the LCD or LED.
4. Reset button to clear the data from the LCD/LED display.
5. External clock for time-stamping.
6. Data logger- records the input counts along with a time stamp for each.
7. External ram to store the data
8. Com/USB port interface to download the stored data.


-which PIC chip to use (18f2550) ?
-has anyone created a unit similar to this?

Not homework, no deadline, just trying to expand my knowledge beyond "blink and led"

Any suggestions would be greatly appreciated.

SteveyD

 

[crutschow]

If you just want to build a breadboard then I suggest using one of the many uP development kits available. Some even include a built-in display.

With that it is just be a matter of generating the software program to do what you want. If you are not familiar with programming then I suggest a kit that uses Basic as a language. It's the easiest way to start with and learn programming. C or Assembly language is more difficult to learn.

I've used a Parallax Basic Stamp 2 and found it easy to use. Others with PIC experience can perhaps recommend some of those.

The time stamp may require a real-time clock if you need to record the date/day/time for example. Those are available as separate modules.

 

[SteveyD]

Thank for the info,

I'd like to make this on a breadboard and then move it to a home-etched pcb.
While a uP development kit would speed things up considerably, I want to understand HOW each step interacts with the one before it.

From the input pulse -> advancing the counter-> displaying the result -> then reset the display by the user(me).
From the input pulse -> capturing the date/time stamp -> storing the data -> retrieving the data -> making sense of the data (displaying it on a PC) -> then rest the stored data by the user(me)

Additional things I'd want to try;
- From the input pulse -> gauge the speed of the input pulses and depending on upper and lower values, have the uC light up a series of LED's based on the input pulse speed (slow=green,medium=yellow,fast=red) <-- this LED sub circuit might be realized by a single red/green 3 pin LED to reduce uC pin outputs.

- using both hardware and software, create two different methods of multiplying the input pulse (by software, 1 pulse advances the memory count by 2 or by hardware split the input pulse into a second delayed pulse to create the same effect.)


I have decided to use a PIC 18F4520 as the uC to facilitate the USB interface option and still have enough output pins to drive both a 7seg LED display(x4 displays = 11 pins), SD card (4-6 pins), LEDs (power and frequency leds = 3 pins

 

[ericgibbs]

hi Steve,
That specification is not going to be easy to work with if you are still learning, USB and SD cards are not easy to program.

I would suggest a 18F2550 [which has USB for later] initially driving a LCD, you will find that a alpha numeric LCD will display ALL the data as the project grows.

EDIT:
A 7 seg LED will be useless for SD development.

 

[SteveyD]

Thanks Eric,

This project is still very much in the concept stages so replacing ideas and hardware is very easy at this point. Cobbling them together to make it work will be the learning part for me.

18F2550 will work fine for what I want to try and I have a few on my desk, I also have a 16x2 LCD unit left over from an abandoned project as well.

I was going to start with a simple counter circuit using the LED segs for display then expand from there, but I can see that maybe a basic PC-USB-PIC(w/LCD) "Hello World" project would be a better place to begin?

 

[ericgibbs]

hi,
Which programming language do you use.?

 

[SteveyD]

I've been working with PICBasic and PICBasic Pro compiler for past projects