mirror of
https://github.com/tinygo-org/drivers.git
synced 2026-07-26 10:38:41 +00:00
Ayke van Laethem
30f540c29f
Tested on the following chips/boards: * RP2040 (Raspberry Pi Pico) * ATSAMD21 (Adafruit PyBadge) * NRF52840 (PCA10056 developer board) * ESP8266 (NodeMCU) * ATmega328p (Arduino Uno) * ESP32C3 (WaveShare ESP-C3-32S-Kit) * FE310 (SiFive HiFive1 rev B) The sensitivity threshold in the example may need to be adjusted per board though, the default value of 100 typically recognizes when a cable is being touched but the RP2040 for example is capable of doing much more precise measurements if the power supply is sufficiently noise-free.
70 lines
1.9 KiB
Go
70 lines
1.9 KiB
Go
// Capacitive touch sensing example.
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//
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// This capacitive touch sensor works by charging a normal GPIO pin, then slowly
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// discharging it through a 1MΩ resistor and seeing how long it takes to go from
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// high to low.
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//
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// Use as follows:
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// - Change touchPin below as needed.
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// - Connect this pin to some metal surface, like a piece of aluminimum foil.
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// Make sure this surface is covered (using paper, Scotch tape, etc).
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// - Also connect this same pin to ground through a 1MΩ resistor.
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//
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// This sensor is very sensitive to noise on the power source, so you should
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// probably try to limit it by running from a battery for example. Especially
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// phone chargers can produce a lot of noise.
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package main
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import (
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"machine"
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"time"
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"tinygo.org/x/drivers/touch/capacitive"
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)
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const touchPin = machine.GP16 // Raspberry Pi Pico
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func main() {
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time.Sleep(time.Second * 2)
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println("start")
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led := machine.LED
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led.Configure(machine.PinConfig{Mode: machine.PinOutput})
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led.Low()
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// Configure the array of GPIO pins used for capacitive touch sensing.
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// We're using only one pin.
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array := capacitive.NewArray([]machine.Pin{touchPin})
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// Use a dynamic threshold, meaning the GPIO pin is automatically calibrated
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// and re-calibrated to adjust for varying environments (e.g. changing
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// humidity).
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array.SetDynamicThreshold(100)
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wasTouching := false
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for i := uint32(0); ; i++ {
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// Update the GPIO pin. This must be called very often.
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array.Update()
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touching := array.Touching(0)
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// Indicate whether the pin is touched via the LED.
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led.Set(touching)
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// Print something when the touch state changed.
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if wasTouching != touching {
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wasTouching = touching
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if touching {
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println(" touch!")
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} else {
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println(" release!")
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}
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}
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// Print the current value, as a debugging aid. It's not really meant to
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// be used directly.
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if i%128 == 32 {
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println("touch value:", array.RawValue(0))
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}
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}
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}
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