The nRf examples here use the Circuit Playground Bluefruit board. If you don't have a JST connector handy, the Circuit Playground Bluefruit can also be equivalently monitored with the VCC and GND clip pads.
The Circuit Playground Bluefruit is a good example of a board that suffers a bit in sleep performance because of parasitic components - since the board has many sensor ICs, the power does not drop very dramatically during deep sleep:
Light sleep is similar, if a bit noisier:
However, other boards may get better power performance depending on their PCB design.
nRF Example
A core NRF feature that makes sense to pair with low power is BLE Advertising. By spacing out advertising with deep sleep in between, a device can periodically signal without draining its battery too quickly. The following sketch shows how this could be implemented in practice:
import time
import adafruit_ble
from adafruit_ble_eddystone import uid, url
import alarm
np = neopixel.NeoPixel(board.NEOPIXEL, 1)
radio = adafruit_ble.BLERadio()
# Reuse the BLE address as our Eddystone instance id.
eddystone_uid = uid.EddystoneUID(radio.address_bytes)
eddystone_url = url.EddystoneURL("https://adafru.it/discord")
while True:
np[0] = (50, 0, 0)
# Alternate between advertising our ID and our URL.
radio.start_advertising(eddystone_uid)
time.sleep(0.5)
radio.stop_advertising()
radio.start_advertising(eddystone_url)
time.sleep(0.5)
radio.stop_advertising()
## USB enumeration may take 4-5s per restart
time_alarm = alarm.time.TimeAlarm(monotonic_time=time.monotonic() + 10)
np[0] = (0, 0, 0)
alarm.exit_and_deep_sleep_until_alarms(time_alarm)
You can learn more about BLE Advertising in the official Learn Guide.
Boot.py:
Page last edited March 08, 2024
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