DIY Controller (Atmel based)

[KrazyKuch]

Yeah thats basically how all probes work.....All you have to do is amplifi the signal to a stat that is easily readable from your controller then it's a matter of figuring out how the signal gets converted into the proper reading.....for PH after it's amplified 1 millivolt will stand for a ph of 1 a 10 millivolt signal stands for a ph of 10....If you want I can get the calculations for the orp!

[kwirky]

what's that on the far lefthand side that was cut off in the schematic labeled "X1"?

What about having software callibration? Which pots would be cut out for software callibration? (for example, put probe in ph 7 solution, press button. put ph probe in ph 10 solution, press button)

[KrazyKuch]

The X1 in that schematic is the BNC connector.....basically that schematic is for orp...I have another for PH if you want it, well basically you can remove the 2 variable resistors and thats all the one that is on the orp is a set it once and never again kinda dealy...

[Robw]

With the schematic link I posted you calibrate the amp with a volt meter and your calibration solutions so you get appropriate readings. This output would be sent to an A/D converter for the atmega board and the value read by one of the input ports. Does the board have any built in A/D converters?

Rob

[KrazyKuch]

It's th3 ATmega 128 if I remember correctly it has 8 10bit A/D ports!

[kwirky]

yeah I understand the two schematics now. I'm probably going to go with the controller schematics here: http://emesystems.com/OL2ph.htm

I've been reading up on the LCD controllers i ordered and I've been toying with AVR tools to figure out efficient ways to interface with LCD controllers.

My goal is to use the 128x64 screen for graphing of logs (temperature, ph, orp, etc). The 128x64 uses dual KS0108's. I also have a 16x4 character LCD ordered that uses the HD44780 controller. I wonder if it'd also have dual controllers because most of the info I've found on the HD44780 pertains to a 2 line screen. we'll see.

I'm waiting on the parts to arrive. they haven't even shipped them yet and I paid extra for express shipping. *grumble grumble*

[KrazyKuch]

I have found the best way to deal with LCD and Micro controllers is building the LCD with another chip and comunicate between the 2 serialy(i.e make a serial LCD)....saves on I/O pins on your controller!!!