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Devices & Hardware

A node graph decides what your experiment does; devices are how it touches the real world. This page covers adding boards, adding devices, binding a device to a node, and how GLIDER decides the range a value is allowed to take.

Boards vs. devices

GLIDER separates hardware into two layers:

  • A board is the controller you plug into — an Arduino, a Raspberry Pi, or a Bluetooth LE link. It owns the physical pins and the connection.
  • A device is a meaningful thing wired to that board — an LED, a button, a servo, an ADC chip. A device turns raw pins into named actions like on, off, set, or read, so your nodes never have to think in pin numbers.

You add a board first, then add devices onto it.

Adding a board

Open Hardware → Add Board.... Pick a board type:

Option in the dialog Hardware Notes
telemetrix Arduino Needs the Telemetrix4Arduino firmware flashed on the board. Choose the serial port (or let GLIDER auto-detect it).
pigpio Raspberry Pi Uses the Pi's own GPIO. No serial port needed.
bluetooth Bluetooth LE Connects to a BLE peripheral. No serial port — the address is set on the device.

Give the board an ID (or accept the default), pick a serial port where it applies, and confirm. Once boards are added, connect them all with Hardware → Connect All (and Disconnect All to release them).

No hardware? Design offline.

You can build and even run a graph with nothing connected. Add real boards and devices when you're ready — the graph doesn't change.

Adding a device

Open Hardware → Add Device... (you need at least one board first). Choose a device type, give it a Device ID and pick the Board it lives on, then fill in the pins and settings the dialog shows for that type.

The built-in device catalog

Device type Dialog name What it does Pins / key settings
DigitalOutput Digital Output (LED, Relay) Drive a pin HIGH or LOW output pin
DigitalInput Digital Input (Button, Sensor) Read a pin as on/off input pin (optional pull-up)
AnalogInput Analog Input (Potentiometer) Read a voltage as a number input pin
PWMOutput PWM Output (Dimmable LED, Motor) Drive a pin at a variable level output pin
Servo Servo Motor Move a servo to an angle signal pin; min/max angle
MotorGovernor Motor Governor Step a motorized position up/down up, down, signal pins
StepperA4988 Stepper Motor (A4988) Drive a stepper via an A4988 driver step, dir, enable, ms1–ms3
ADS1115 ADS1115 (I2C ADC) 16-bit analog readings over I2C I2C address, gain, data rate
GenericI2C Generic I2C Device Talk to any I2C chip by address I2C bus, address, register
BLEWrite BLE Device (write characteristic) Send string commands to a BLE peripheral BLE address, characteristic UUID

The full device reference

Each device exposes its own set of actions (for example, a PWMOutput has set, set_percent, and off). For the complete list of actions per device, see the Device Catalog.

I2C, ADC, and Bluetooth specifics

  • ADS1115 and Generic I2C don't use GPIO pins — on a Raspberry Pi the I2C data and clock lines are fixed. You configure them by address (and, for the generic device, a register) instead of pins.
  • BLE Device connects to a Bluetooth peripheral by address and writes string commands (like on, off, or 20,10) to a characteristic. The Add Device dialog can Scan for nearby peripherals so you don't have to type the address by hand.

Binding a device to a node

A hardware node is inert until you tell it which device to act on. This is binding.

  1. Add a hardware node to your graph — for example an Output node.
  2. Select it, and in the Properties panel find the Device dropdown.
  3. Pick your device from the list (it shows each device's name and type).

The device dropdown appears for these nodes: Output, Input, WaitForInput, MotorGovernor, and Device Action.

One node, many kinds of hardware

The generic Output node adapts to whatever it's bound to: bound to a digital device it writes HIGH/LOW; bound to a PWM device it writes a level. Likewise Input reads digital or analog depending on its device. That's why most experiments use a handful of Output and Input nodes rather than a different node per pin.

Device Action: calling a named action

The Device Action node is the general-purpose way to invoke any action a device offers. After binding a device, its Action dropdown lists that device's available actions (like set, read, write, up, down). You can also type constant Arguments — split on commas, with numbers detected automatically — which are passed to the action when no data inputs are wired. This is how you'd send a BLE write command such as on, off, or 20,10.

How a value's range is decided

When a node writes a value to a device — a PWM level, a servo angle, a pump rate — GLIDER needs to know what range that value can legally take. Rather than hard-coding a range, each device declares the range for each of its actions, and every layer (the property editors, the Runner controls, and the write itself) reads that single declaration. This is called the value's spec.

The practical upshots:

  • PWM depends on the board's resolution. On an 8-bit board a PWM value runs 0–255; on a 12-bit board it runs 0–4095. The same Output or PWM Write node adapts to whichever board its device is on — it's never silently capped at 8-bit.
  • A servo is bounded by its configured angle. If you set a servo's min/max to 0–180, commanding 200 lands at 180.
  • On/off devices are a 0–1 switch. A digital set action takes just on or off.

If you write a value outside the allowed range, GLIDER clamps it to the nearest legal value rather than letting it wrap around to a wrong number. A non-numeric or infinite value is rejected outright.

Out-of-range saved values are flagged at load

If you saved a value into a node (say, an Output set to 1000) and later changed the bound device so that value no longer fits its range, GLIDER warns you when the experiment loads that the stored value will be clamped — so a range change never silently rewrites your experiment mid-run.

Keeping hardware safe

  • Connect All / Disconnect All (Hardware menu) bring every board online or release them.
  • Emergency Stop (Run → Emergency Stop, Ctrl+Shift+Esc) immediately drives devices to a safe state — outputs off, motors stopped — without waiting for the graph to finish.

Where to go next