This is an email that I had written to Parallax when I was trying to redirect readings from a WattsUp Meter to a data logger. I had just started out with basic stamp programing a year before this. It’s suppose to be humor, but it sure would be helpful if this actually could work, especially come Lotto day!
From: Patrick circa 2014
Sent: Wednesday, March 19, 2014 5:27 PM
To: Patrick circa 2010
Subject: RE: BS2pe Data Logger Application
Hi Patrick circa 2010-
You will be me in 4 years. To answer your question, yes. But it isn’t easy.
This is what is going on…
The AVR is sending nibs of data on those 4 digital lines, DB4-DB7 to be exact. Each nib represents a lower or upper portion of a byte. The LCD gets instruction from the AVR and pieces them together. From there, the LCD can read the byte value and determine what to do. There are 256 possible values for each byte. Some bytes initialize the LCD…some clear the screen…some choose the cursor position…while others are the values to place on the screen. There’s a lot going on and it happens really fucking fast.
In order to do what you want to do, you’ll need to program the BS2pe to listen to the data and control pins of the AVR. It will need to interpret the nibs and create bytes, just like the LCD. Next, you will need to program the BS2pe to take actions that match the output of the LCD. These would include, initialize, clear screen, set cursor position, write value, etc. Finally, since you want to data log the values, you would need to program when to log values as they are buffered.
Can it be done, maybe. I’m not sure if there’s enough memory for the code to fit. I’m thinking it’s going to be fairly complex. It’s a large amount of work to create this. The BS2pe is unlike the Prop and Arduino micro controllers, which you have yet to study, it doesn’t benefit from libraries. You would be better off creating a library to that acts as a software LCD emulator. From there you could create lighter code.
What would you do in 4 years? I’ll tell you. You would use a current sensor and take the readings from that to a micro controller and output the data as you please. Really, it’s that easy. Forget about hacking into the WattsUp meter and trying to sniff values out of it. Your time would be better represented keeping that meter in factory condition and using your own sensor and processing device.
Keep your chin up kiddo, you’ll do fine.
-Patrick circa 2014
From: Patrick circa 2010
Sent: Friday, February 12, 2010 8:42 AM
Subject: BS2pe Data Logger Application
I have a question about the ability of the BS2pe to provide data logging from an external microcontroller.
Currently, I have a AVR Microcontroller that outputs voltage reading to a LCD display. Here is a basic wiring example of that system.
Can the BS2pe replace the LCD display and store values from the AVR Microcontroller? Thank you for your time.