I have been searching for a little while about ways to accomplish my goal and have found a lot of useful information on this site and others. Figured I would reach out to see if anyone had any input before I actually get started.
First, I must say I haven’t yet touched an Arduino but plan on ordering one as soon as I get feedback on which one to get. I have 20+ years working on scales specifically some of which included automation and system control however most of this was accomplished with specific parts and equipment supplied by a manufacturer.
Now I want to try to make this work myself.
I believe it will be easy to do but again, would like some feedback before I start throwing good money after bad.
Control a relay based on weight.
Using a weight scale with a continuous serial output; String looks like:
= ASCII: 02 decimal
= Polarity: < space> = Positive,<–> = Negative
= Weight: 7 digits, right-justified, dummy zeroes, decimal point with no leading
zeroes except for leading zero immediately preceding the decimal point. Leading zeroes transmitted as spaces.
= L: pounds, K = kilograms, T = tons, G = grains, = grams, O = ounces,
<G/N> = G: Gross, N = Net
= Status: < space> = valid, I = Invalid, M = Motion, O = Over/under range, Z = COZ
= Terminator: CR LF carriage return and line feed, CR carriage return
Example string could be: 02 1234567LG CR
Would need to look at the 7 characters #5 through #11 and use that number to control the relay based on a setpoint entered into the program.
Basic example operation would be:
Enter Target: 1.00
Press Start: Relay closes, open relay once target is achieved.
It will get slightly more complex later, but for starters that is the goal.
Future additions might be to have the program look at the weight at the beginning, and essentially auto-tare or note the starting reading and add the target to the current reading or look at string for Z or M in character 14 and respond accordingly. Press start, if character 14 is not Z don’t start.
Possibly add additional relays to control conveyors, multiple ingredients, etc…
Yes, I could buy a programmable indicator for around $2000 that could read the serial string and react accordingly but then I don’t get to learn anything nor get the satisfaction of making this work myself (somewhat) and save money at the same time and maybe get automation into the hands of people that otherwise couldn’t afford it.
Most of the scales in use would be used in a “legal for trade” (buying or selling by weight) application so alternative scale options aren’t possible. The idea is to be able to add the Arduino to basic equipment already in operation without having to upgrade everything.
Any help, ideas or suggestions are appreciated.