The Ekdahl FAR - Command reference V1.1

Introduction

The Ekdahl FAR V1.1 introduces the concept of modules. A module can contain any number of commands as well as other modules. Furthermore any number of modules of the same type can exist within a context, these are addressed using classic C-style array indexing with the help of brackets ("[ ]"). Extending on the classic usage, multiple indexes can be addressed simultaneously by either comma-separating the objects ("[0,3,4]") and using ranges ("[3-6]"). Modules can be either internal or external, meaning that they may all physically exist within a single hardware object, or they can be be remote-controlled devices. From a user perspective this however makes no difference as they will appear the same.

While all modules have their own set of commands, there are certain commands that all modules must implement and can thus be accessed anywhere within the module hierarchy. There are also base commands that always exist within any given FAR ecosystem as well as product-specific base commands.

Basic commands

The module commands that are required to be implemented in all modules and that can thus be accessed from anywhere are

Long name	Short name	Parameters	Description
list	ls	hidden/h:modules/m:commands/c:instances/i:instancecounts/ic:recursive/r	Lists all commands and modules under the current module depending on the parameters given; 'hidden' includes normally hidden commands, 'modules' includes any submodules, 'commands' shows commands, 'instances' shows data for each individual instance of a module, 'instancecounts' includes number of instances of each module, 'recursive' lists all child modules / commands. No parameters defaults to showing all commands and modules recursively with instance counts. It doesn't show per-instance data or hidden commands.
help	help	recursive/r	Shows a brief explanation of all commands and modules, shows the help for all submodules as well if 'recursive'
dumpdata	dump	recursive/r	Dumps all data saved for the current module, will list the data of all submodules as well if 'recursive'

The base commands are as follows

Long name	Short name	Parameters	Description
version	ver	-	Gets the current firmware version
debugprint	dp	command|usb|hardware|undefined|priority|error|inforequest|expressionparser|debug:1|0	Turns on or off serial feedback for the given item
requestinfo	rqi	command	Retrives any data saved for a command, if applicable
saveallparameters	sap	-	Saves all avaliable parameters
loadallparameters	lap	-	Loads all avaliable parameters
resetallparameters	rap	-	Resets all saved parameters
reset	rst	1|0	Resets the Ekdahl FAR, conditional
nick	nick	name	Sets the nickname of this unit
nooperation	nop	-	Do absolutely, positively, nothing. Useful for testing and interfacing with computers, it's a good way to know that the unit is alive and responding since a "nop" is being returned as a response upon reception.
uservariable	uv	variable(0-9):value	Set user variable 0-9 to 'value'
expressionparserevaluate	epev	expression	Evaluates an arithmetric expression and sends back the output, all variables and functions that can be used in any command string can also be used here. Useful for testing expressions.
ifequal	ife	variable:comparator:truecommandstring:elsecommandstring	Performs [IF [variable] EQUALS [comparator]] then add [truecommandstring] to the que if TRUE, otherwise add [elsecommandstring].
ifgreater	ifg	variable:comparator:truecommandstring:elsecommandstring	Performs [IF [variable] > [comparator]] then add [truecommandstring] to the que if TRUE, otherwise add [elsecommandstring]
ifless	ifl	variable:comparator:truecommandstring:elsecommandstring	Performs [IF [variable] < [comparator]] then add [truecommandstring] to the que if TRUE, otherwise add [elsecommandstring]
freeram	ram	-	Shows free RAM memory

The base also contains the following modules:

Long name	Short name
pluginhandler	ph

The Ekdahl FAR stand alone single string unit

The Ekdahl FAR stand-alone single string unit offers these commands

Long name	Short name	Parameters	Description
calibrateall	ca	-	Performs all calibration routines on the selected bow, see below for routines performed
calibratebowspeed	cbs	-	Finds the minimum and maximum bow speed of the selected bow
calibratebowpressure	cbp	-	Finds the minimum and maximum bow pressure of the selected bow
calibratemute	cmu	-	Calibrate mute settings
pickupstringfrequency	psf	-	Returns the fundamental tone calculated from the current audio signal if apliccable
pickupaudiopeak	pap	-	Returns the peak amplitude of the current audio signal
pickupaudiorms	par	-	Returns the RMS amplitude of the current audio signal

The Ekdahl FAR also contains the following modules

Long name	Short name
bowingwheel	bw
mute	mu
solenoid	so
controlbox	cb
midiconfigurationhandler	mcf

The "bowingwheel"-module

The "Bowingwheel"-module contains everything needed to interface with a single bowing wheel. Each bowing wheel has its own harmonic series, pressure actuators and direct hardware interface. It contains the following commands.

Long name	Short name	Parameters	Description
speedmode	sm	0|1	Bow motor speed mode, 0 = Automatic and 1 = Manual. Automatic mode means that the bowing wheel will automatically turn off after the motor timeout has been reached after being put into rest mode
motortimeout	mt	ms	Bow motor shutdown timeout after bow having been put into the rest position
pidenable	pe	0|1	Sets the bow PID on/off
motorfaultcommands	mfc	commands	Commands to execute when a motor fault is tripped - !WARNING! Can ruin your instrument if changed
motoroverpowercommands	moc	commands	Commands to execute when motor is over the power limit - !WARNING! Can ruin your instrument if changed

The modules in the "Bowingwheel"-module are as follows

Long name	Short name
bowpressure	bp
dcmotor	dcm
pid	pid
harmonicserieshandler	hsh

The "bowpressure"-module handles the pressure of the bowing wheel against the string. The "bowpressure"-module has the following commands

Long name	Short name	Parameters	Description
baseline	ba	0-65535	Bow pressure baseline, modulation is added to this point upward. Typically this is set with a knob on the control box
modifier	mo	0-65535	Bow pressure modulation, added to the baseline
rest	rs	0|1	Puts the bow pressure in the rest position, conditional
engage	en	0|1	Puts the bow pressure in the engage position, conditional
stallpressure	sp	0-65535	Bow pressure stall/maximum position, this parameter is set using hardware positioning and is used as the absolute maximum for baseline and modifier combiner
engagepressure	ep	0-65535	Bow pressure touch/minimum position, this parameter is set using hardware position and is used as the starting point for when both the baseline and modifier is set to zero
restpressure	rp	0-65535	Bow pressure rest position, this parameter is set using hardware positioning and is typically set to a point just below the string where it does not touch at all. The purpose of this is because while the actual hardware might be able to make the bow go even lower, that position might be far enough from the string that once engaged the bow may have so far to travel that there is perceptible latency.
engagespeed	es	1- ~100	Bow pressure movement speed when engaging or disengaging
modulationspeed	ms	0.1 - 10	Bow pressure movement speed while engaged
hold	hd	0|1	Sets bow hold (infinite sustain) on/off, conditional
home	hm	-	Homing bow, used at startup and in case of the bow loosing position
tmcinfo	tmi	-	Request statistical information from the TMC2209 stepper motor driver

Note that the "stall", "engage" and "rest"-pressure positions mention something called hardware position. This means the entire available movement of the bowing jack. Because the very bottom and top end of the movement might not be musically useful and may even harm the instrument, the "baseline" and "modifier" commands parameters are scaled depending on these settings.

The "engage" and "modulation"-speed settings sets how fast the stepper motor that drives the pressure moves depending on whether the bowing jack is set to engage or not. The idea here is that while wanting to be able to minimize latency by engaging and disengaging from the string as quickly as possible, dynamic changes in the pressure while playing benefits from much smoother movements as the bowing wheel takes some time to catch up to varying amounts of friction.

The "dcmotor"-module handles the direct raw control of the bowing motor and handles the reporting back of the current speed. It has the following commands:

Long name	Short name	Parameters	Description
run	ru	0|1	Turns the motor off/on
pwm	pw	0-65535	Bow motor direct power in 16-bit PWM values, requires that the PID is turned off
voltage	vo	~2 - 10V	Sets the voltage of the regulator powering the motor. Changes here can make the motor more responsive to certain frequencies but will also affect how well the PID works. !WARNING! CAN RUIN YOUR INSTRUMENT IF CHANGED
current	cu	float	Bow motor reported current use
currentlimit	cl	float	Bow motor current limit (A)- !WARNING! CAN RUIN YOUR INSTRUMENT IF CHANGED
powerlimit	pl	float	Bow motor power limit (W) - !WARNING! CAN RUIN YOUR INSTRUMENT IF CHANGED
frequency	fq	float	Bow motor reported frequency
emergencystop	es	ms (0-65535)	Immediately stops the bowing motor and doesn't allow it to start again until the cool down period given in the first argument has lapsed (milliseconds)
minpwm	ip	0-65535	Bow motor minimum PWM (for calibration)
maxpwm	xp	0-65535	Bow motor maximum PWM (for calibration)

The "pidcontroller"-module is responsible for keeping the "dcmotor"-module at a certain frequency (given in Hertz). It takes the output of the motor frequency measurement and feeds it a PWM value that tries to make the speed constant regardless of the friction that the motor is enduring. To learn more about PID Controllers please see this wikipedia article. The module has the following commands:

Long name	Short name	Parameters	Description
targetfrequency	tf	hertz	Sets the PID target frequency
ki	ki	float	Sets the Ki parameter of the PID
kp	kp	float	Sets the Kp parameter of the PID
kd	kd	float	Sets the Kd parameter of the PID
integratorerror	ie	float	Sets the lower threshold of error values for the PID integrator to ignore
reset	re	-	Resets the PID integrator and derivative
maxerror	xe	float	Maximum error to correct in each PID loop, essentially sets acceleration
peakerror	pe	float	Get latest PID peak error
motorspeedmax	msx	Hertz	Bow motor maximum speed limit
motorspeedmin	msi	Hertz	Bow motor minimum speed limit
measuretimetotarget	mtt	Hertz	Measure the time it takes to change from the current frequency to the target frequency, for testing purposes

The "harmonicserieshandler"-module is responsible for sending frequency data to the "pid"-module. It handles calculating the correct frequency of the bowing wheel according to the selected harmonic and harmonic shift per the currently selected harmonic series. The "harmonicserieshandler"-module has the following commands:

Long name	Short name	Parameters	Description
fundamental	fu	Hertz	The fundamental frequency of the string, all harmonics are calculated from this number
harmonic	h	int	Selects the harmonic number to set the bowing wheel to. A ratio is taken from the given harmonic in the current harmonic series, the ratio is then multiplied by the fundamental frequency
harmonicadd	ha	int	This number is added to the current harmonic
harmonicbase	hb	int	Same as harmonic but where the harmonic number is based on a MIDI note given by basenote
basenote	bn	0-127	Sets the MIDI base note of the bowing wheel, used in conjunction with "harmonicbase"
shift	sh	-32767 - 32767	Sets shift from the currently playing harmonic where 32767 equals the entire harmonic shift range shifted up
shiftrange	sr	0-36	Set the number of harmonic numbers that constitutes an entire harmonic shift
shift5	sh5	-32767 - 32767	Sets the shift from the currently playing harmonic over 5 octaves where 32767 equals 5 octaves shift up from the fundamental
add	a	(name):(ratios)	Add a new series with the given name and parameters
remove	rm	series	Remove the series given and shift any series accordingly. Cannot remove all series
count	c	-	Returns the number of harmonic series in the list and their IDs

The "harmonicserieshandler"-module contains at the very least ONE harmonic series, by default it contains two: one for equal temperament and one for just intonation. The current series can be selected by simply indexing the "harmonicseries"-module without a command, e.g. "harmonicserieshandler.harmonicseries[1]". To be consistent, these are the modules in the "harmonicserieshandler"-module:

Long name	Short name
harmonicseries	hs

The "harmonicseries"-module contains any number of ratios that comprises a scale, ratios are given in a standard format where a ratio of "1" is equal to the fundamental, "2" would be one octave up etc. A standard harmonic series contains 12 ratios following a just intonation scheme. The "harmonicserieshandler"-module will automatically adapt to the currently selected harmonic series length, whether it's a standard 12-tone scale, some kinda 3-tone scale or a full on bananas 53-tone scale. The commands of the "harmonicseries"-module is as follows:

Long name	Short name	Parameters	Description
[index]	-	-	Sets the currently selected harmonic Series
name	na	string	Sets the name of the harmonic series
data	da	name:ratios	Gets / sets all data for the harmonic series in the given slot with an arbitrary name as the first parameter. The length of the series is simply set to the amount of ratios given
ratio	r	harmonic:ratio	Sets the ratio of the given harmonic in current harmonic series, will increase the list size if needed to address the harmonic
remove	rm	harmonic	Remove the harmonic ratio given in the current series and shift any ratios accordingly. Cannot remove all ratios

The "mute"-module

The "mute"-module works very similarly to the "bowpressure"-module in that it controls a stepper motor with some software limits in place in order to press the mute against the string. The commands are as follows:

Long name	Short name	Parameters	Description
setposition	sp	0-65535	Set mute position
fullmute	fm	0|1	Puts the mute in full mute position, conditional
halfmute	hm	0|1	Puts the mute in half mute position, conditional
rest	rs	0|1	Put the mute in the rest position, conditional
savefull	sf	0|1	Save the current mute position as the full mute position, conditional
savehalf	sh	0|1	Save the current mute position as the half mute position, conditional
saverest	sr	0|1	Save the current mute position as the rest position, conditional
fullmuteposition	fmp	0-65535	Sets the full mute position according to the hardware position given
halfmuteposition	hmp	0-65535	Sets the half mute position according to the hardware position given
restposition	rp	0-65535	Sets the rest position according to the hardware position given
sustain	su	0|1	Sets the sustain off/on, this will keep the mute in the rest position even if a "fullmute"-command is given, lasts until "sustain" is set to "0".
backoff	bo	0-65535	Setting the time that the mute stays in the mutefullmute position before automatically going into rest, set in mS. A value of "0" disables backoff. This is used because if the mute is not backing off until something is attempted to be played, the backing-off time will either introduce latency or the string will be initially partially muted
home	hm	-	Home mute, used during initialization and if the mute were to loose position
hardwareposition	hwp	0-65535	Sets the hardware position of the mute instead of scaling it over the full mute and rest positions. Mainly used internally by other modules
completetask	cpt	-	Requests a callback when the current operation is finished. Only used internally by other modules
autocorrect	ac	0|1	Enables auto correct positioning that uses the homing sensor to correct positioning on the fly. EXPERIMENTAL
homingsensed	hms	-	Requests whether the homing sensor is currently active or not. Only used internally by other modules
movedirection	md	-	Requests the current direction of movement (0 Forward, 1 Reverse). Only used internally by other modules
currentstep	cs	-	Requests the current step. Only used internally by other modules
homingpoint	hmp	edgedirection	Requests the given homing point. Only used internally by other modules
homingstage	hms	-	Requests the current homing stage (UNHOMED, HOMED, FIRSTHOMINGRISING, SECONDHOMINGFALLING, SECONDHOMINGRISING, FIRSTHOMINGFALLING, MOVEPASTHOMESWITCH, MOVETOHOMESWITCH, GOTOOFFSET). Only used internally by other modules.
tmcinfo	tmi	-	Request statistical information from the TMC2209 stepper motor driver