Dual magnetic stir controller

Overview

This is the Arduino sketch to build a double magnetic stirrer based on 2 fans, a 1602 LCD display, a KY-040 encoder and an Arduino (e.g. Uno, Nano, Leonardo, Pro Micro).

In order to put the stirrer into operation you have to change the settings in stir.ino according to your setup.

Reference

This project was created based on an idea from the Hobbybrauer-Forum and would not be possible without the ideas from there.

The forum: https://hobbybrauer.de/

The thread: https://hobbybrauer.de/forum/viewtopic.php?f=21&t=1456

Overview of Functions

All functions are controlled by the KY-040 encoder:

• Short Press: change between menu, stirrer 1 and stirrer 2
• Turn when menu is selected: change between menu items (SPEED, BOOST, BTIME, CATCH, CTIME)
• Long press when menu is selected: lock all functions (unlock also by long press)
• When a stirrer is selected:
  • SPEED: turn sets speed, long press switches stirrer on or off.
  • BOOST: turn sets boost speed, long press activates/deactivates the boost function (running time is shown in the display).
  • BTIME: turn changes the boost time in minutes.
  • CATCH: turn activates/deactivates the fishing function
  • CTIME: turn changes the interval in minutes for the fish catching function
  • RTIME: turn changes speed rise time in seconds (applies to power on, stirrer on, boost on and fish catching)
  • OTIME: turn changes switch off time in hours (the timer activates immediately, 0 = switch off disabled)
  • RNVAL: random value range (a random values in this range will be added to speed)
• Other menu options:
  • BRGHT: LCD brightness

Display Indicators:

• Bottom Left: Menu
• Bottom Center/Right: displays the set values for the stirrers depending on the selected menu item.
• Top Center/Right: displays the current stirrer speed (or 'OFF' or 'CAT' (Fishing)).
• Top Left: shows the remaining time of the boost or switch off function.

Settings (in stir.ino)

Value	Description
SPEEDINC	increment of speed values when turning the encoder
FANMIN	fan minimum speed (should be a value at which the fan runs safely) (rpm)
FANMAX	maximum speed of the fan (it is important that this is the real maximum value of the fan) (rpm)
BOFF	if set boost off will also turn the normal mode off
BINC	boost time increment (min)
CINC	catch time increment (min)
RINC	rise time increment (sec)
OINC	off timer increment (hour)
CATCHSTOP	stop interval for stir fish catch function (ms)
PWM0, PWM1	PWM output pins for fan speed
PWM2	PWM output pin for LCD brightness control
I0, I1	interrupts for rpm measurement (2 and 3 for Leonardo and ProMicro / 0 and 1 for Uno)
CLK, DT, SW	pins for KY-040 encoder
OFF0, OFF1	these pins will be set if the fan is off
OFFSTATE	off state (LOW/HIGH)
RINTERVAL	regulation interval (ms)
RDELAY	extra regulation delay when value changes (ms)
RTOL	regulation tolerance (rpm)
RNDINTERVL	randon value range change interval (ms)
SINTERVAL	speed measurement interval (ms)
SAVERAGE	speed measurement average
SAVETAG	parameter save identifier
SAVEDELAY	delay in seconds before parameter will be saved to EEPROM
LCDB	LCD brightness steps (10 values, 0=off, 255=max)

API commands

Commands are colon separated an can be send via USB/Serial

Command	Description
info	returns a colon separated string with all parameters (see below)
version	returns the software version
on:<0/1>	switch stirren on
off:<0/1>	switch stirren off
bon:<0/1>	switch boost mode on
boff:<0/1>	switch boost mode off
speed:<0/1>:<rpm>	set stirrer speed (FANMIN-FANMAX rpm)
bspeed:<0/1>:<rpm>	set stirrer boost speed (speed-FANMAX rpm)
btime:<0/1>:<min>	set boost time (0-60)
con:<0/1>	switch catch mode on
coff:<0/1>	switch catch mode off
ctime:<0/1>:<min>	set catch mode interval (60-240 min)
rtime:<0/1>:<sec>	set speed rise time (0-240 sec)
rnval:<0/1>:<rpm>	set randon value range (0-1000 rpm)
otime:<0/1>:<hour>	switch stirrer off after time in hours (1-99 hour, 0 deactivates switch off)

All commands return a colon separated string with all current parameters:

Element	Stirrer	Variable in stir.ino	Description
0	0	F[0]	state (0=on, 1=off)
1	0	v[0]	speed (rpm)
2	0	b[0]	boost speed (rpm)
3	0	rpm[0]	rpm
4	0	xpm[0]	averaged rpm
5	0	r[0]	regulation value
6	0	bstate[0]	boost state (0=on, 1=off)
7	0	btime[0]	boost time (min)
8	0	cat[0]	fish catch mode state (0=on, 1=off)
9	0	ctime[0]	fish catch time interval (min)
10	0	rtime[0]	speed rise time (sec)
11	0	otime[0]	switch off time (hour)
12	0	rnval[0]	random value range (rpm)
13	0	rnd[0]	current random value (rpm)
14	0		boost remain (sec)
15	0		off timer remain (sec)
16	1	F[1]	state (0=on, 1=off)
17	1	v[1]	speed (rpm)
18	1	b[1]	boost speed (rpm)
19	1	rpm[1]	rpm
20	1	xpm[1]	averaged rpm
21	1	r[1]	regulation value
22	1	bstate[1]	boost state (0=on, 1=off)
23	1	btime[1]	boost time (min)
24	1	cat[1]	fish catch mode state (0=on, 1=off)
25	1	ctime[1]	fish catch time interval (min)
26	1	rtime[1]	speed rise time (sec)
27	1	otime[1]	switch off time (hour)
28	1	rnval[1]	random value range (rpm)
29	1	rnd[1]	current random value (rpm)
30	1		boost remain (sec)
31	1		off timer remain (sec)
32			software version
33			uptime (ms)
34			0=ok, 1=error

Schematics