A Sample script for the not-things TimeSeq module.
Because voltage values on output ports and variables within TimeSeq are only changed when an action updates them, implementing sample-and-hold-like behaviour can be easily done in TimeSeq. This page will demonstrate basic S&H behaviour using input sources and triggers, and expand on this by using internally generated voltages, trigger timings and combinations of values.
The first S&H aspect that we will set up is the basic S&H principle: sample the voltage from an input source every time an external trigger is received, and hold that value on the output port until the next trigger is received. We’ll set up four of these, each having their own input source and individual trigger.
In the sample VCV Rack patch that is linked to below, they will be connected to three LFO output signals (a sine, triangle and sawtooth signal) and to a noise output (i.e a random value). So that’s what we’ll also call them in the script.
To keep a better overview in this script, we’ll define re-usable input and output definitions in the component-pool that we can then reference by their ID throughout the rest of the script, choosing IDs that specify what the ports are used for.
We’ll use four input ports, combining each input voltage (from the LFO and Noise modules) with the corresponding trigger on the same port using different channels: channel 1 will be the input voltage, channel 2 will be the corresponding input trigger. This results in following input definitions:
"component-pool": {
"inputs": [
{
"id": "input-sine-source",
"index": 1,
"channel": 1
},
{
"id": "input-sine-trigger",
"index": 1,
"channel": 2
},
{
"id": "input-triangle-source",
"index": 2,
"channel": 1
},
{
"id": "input-triangle-trigger",
"index": 2,
"channel": 2
},
{
"id": "input-sawtooth-source",
"index": 3,
"channel": 1
},
{
"id": "input-sawtooth-trigger",
"index": 3,
"channel": 2
},
{
"id": "input-noise-source",
"index": 4,
"channel": 1
},
{
"id": "input-noise-trigger",
"index": 4,
"channel": 2
}
]
}
Similar to the inputs, we’ll also add output definitions to the component-pool, one for each of the four result signals:
"outputs": [
{
"id": "output-sine",
"index": 1
},
{
"id": "output-triangle",
"index": 2
},
{
"id": "output-sawtooth",
"index": 3
},
{
"id": "output-noise",
"index": 4
}
]
To make it easier in VCV Rack to identify which output contains which output signal, we’ll also update the tooltip labels of the outputs using a set-label action in the global-actions property of the script:
"global-actions": [
{ "set-label": { "index": 1, "label": "Sine S&H"} },
{ "set-label": { "index": 2, "label": "Triangle S&H"} },
{ "set-label": { "index": 3, "label": "Sawtooth S&H"} },
{ "set-label": { "index": 4, "label": "Noise S&H"} }
],
With the inputs and outputs set up, we’ll have to hook up the input-triggers so that a trigger signal received on one of the trigger inputs can be used as a starting point for the S&H action to be performed:
"input-triggers": [
{ "input": { "ref": "input-sine-trigger" }, "id": "sine-trigger" },
{ "input": { "ref": "input-triangle-trigger" }, "id": "triangle-trigger" },
{ "input": { "ref": "input-sawtooth-trigger" }, "id": "sawtooth-trigger" },
{ "input": { "ref": "input-noise-trigger" }, "id": "noise-trigger" }
]
This will cause an internal trigger with the corresponding ID to be fired when an external trigger signal is detected.
The configured internal triggers can now be used in the start-trigger property of lanes that will perform the sampling of the input voltage. The sine signal sampler would be:
{
"start-trigger": "sine-trigger",
"segments": [
{
"duration": { "samples": 1 },
"actions": [
{
"set-value": {
"output": { "ref": "output-sine" },
"value": { "input": { "ref": "input-sine-source" } }
}
}
]
}
]
}
The lane doesn’t auto-start, but instead is started when the sine-trigger is fired by the corresponding input-trigger definition. The lane doesn’t loop and it contains only one segment that lasts for a single sample. It will update output-sine output voltage using the current voltage of the input-sine-source input.
A similar lane for each of the other three Sample and Hold targets (triangle, sawtooth and noise) will complete the basic Sample and Hold patch.
The full script can be found at sample-and-hold.json, and the sample-and-hold.vcv patch contains a full setup:
Instead of using external voltage sources, a Sample and Hold action can also sample internal voltages. And instead of writing to an output port, we can also send the voltage to a variable that can be used in other places in the script.
In this step, we’ll sample from an internal random value and send that to both output port 5 (so we can visualize it in the patch) and to a variable that we can use later on.
Following input definition in the component-pool will be used to receive the input trigger for the Sample and Hold action on input port 5:
{
"id": "input-random-variable-trigger",
"index": 5
}
Following output definition in the component-pool will be used to send the resulting Sample and Hold voltage to output port 5:
{
"id": "output-random-variable",
"index": 5
}
And following input-trigger definition will cause the internal trigger with id random-variable-trigger to be fired when the input detects an external trigger:
{ "input": { "ref": "input-random-variable-trigger" }, "id": "random-variable-trigger" }
The new lane to perform the Sample and Hold action will then look as follows:
{
"start-trigger": "random-variable-trigger",
"segments": [
{
"duration": { "samples": 1 },
"actions": [
{
"set-variable": {
"name": "random-variable",
"value": {
"rand": {
"lower": -5,
"upper": 5
}
}
}
},
{
"set-value": {
"value": { "variable": "random-variable" },
"output": { "ref": "output-random-variable" }
}
}
]
}
]
}
It generates a random value between -5 and 5 volts and using a set-variable action assigns it to the a variable named random-variable. This variable is then used to update the output-random-variable output port voltage using a set-value action.
The full script can be found at sample-and-hold-internal-random.json, and the sample-and-hold-internal-random.vcv patch contains the full setup.
The patch adds another LFO to generate the trigger for the fifth input port and visualizes the resulting voltage output on another Scope.
The stored previously stored variable (with id random-variable) can also be used by other lanes to generate new signal combinations. In this step, we’ll use the raw sine input from the first step, and offset it with the random-variable.
First we need to define the output that we will receive the resulting voltage:
{
"id": "output-random-variable-plus-sine",
"index": 6
}
To generate an output signal that follows the original Sine signal, we’ll need to set up a lane that starts automatically and loops:
{
"auto-start": true,
"loop": true,
"segments": [
{
"duration": { "samples": 1 },
"actions": [
{
"set-value": {
"value": {
"input": { "ref": "input-sine-source" },
"calc": [
{ "add": { "variable": "random-variable" } }
]
},
"output": { "ref": "output-random-variable-plus-sine" }
}
}
]
}
]
}
The single segment in this lane last for only one sample, so combined with the looping of the lane, it will be executed for every VCV Rack sample. Each time, it will take the current voltage from the sine input, and add the current voltage of the random-variable variable to it using a calc operation. The resulting voltage is then sent to the new output port.
The resulting script can be found at sample-and-hold-sine-offset.json, and the sample-and-hold-sine-offset.vcv patch visualizes the result, showing a Sine signal that jumps up or down each time a new internal random voltage is sampled.
The triggers for a Sample and Hold action don’t have to come from an external source through an input-trigger. A TimeSeq script can also perform the action based on an internal event. This can be an internal trigger, or based on the timing execution of a segment. In this sample, we’ll use the last option: a looping segment will perform the sampling action, with its duration defining the frequency.
First we’ll create a new internal sampling source that we can use for this part of the script: a triangle signal that moves between -5V and 5V:
{
"auto-start": true,
"loop": true,
"segments": [
{
"duration": { "millis": 2333 },
"actions": [
{
"timing": "glide",
"start-value": -5,
"end-value": 5,
"variable": "internal-triangle"
}
]
},
{
"duration": { "millis": 2333 },
"actions": [
{
"timing": "glide",
"start-value": 5,
"end-value": -5,
"variable": "internal-triangle"
}
]
}
]
},
This automatically started and looping lane uses two glide actions to move up and down between -5V and 5V, taking 2.333 seconds for each glide. The resulting moving voltage is stored in the internal-triangle variable.
The following lane can then be used to sample this variable and send it to the output-internal-triangle output:
{
"auto-start": true,
"loop": true,
"segments": [
{
"duration": { "millis": 500 },
"actions": [
{
"set-value": {
"value": {
"variable": "internal-triangle"
},
"output": { "ref": "output-internal-triangle" }
}
}
]
}
]
},
The "millis": 500 duration of the segment makes this Sample and Hold action be executed every half second.
And since we have one more output port available, we can send a similar signal to the sine-and-random-value output to it, but this time combining the random-variable and internal-triangle variables. The resulting output signal will be completely based on internally generated voltages and trigger timings:
{
"auto-start": true,
"loop": true,
"segments": [
{
"duration": { "samples": 1 },
"actions": [
{
"set-value": {
"value": {
"variable": "internal-triangle",
"calc": [
{ "add": { "variable": "random-variable" } }
]
},
"output": { "ref": "output-internal-triangle-plus-random-value" }
}
}
]
}
]
}
The two additional output definitions that are needed to complete this patch are:
{
"id": "output-internal-triangle",
"index": 7
},
{
"id": "output-internal-triangle-plus-random-value",
"index": 8
}
The full script can be found at sample-and-hold-full.json, and the sample-and-hold-full.vcv patch contains a full setup with source signals and output visualization.