User's Guide

Hardware description
6.9 LEDs and buttons
Nordic Thingy:91 user interface consists of RGB LEDs and two buttons.
6.9.1 RGB LED
Nordic Thingy:91 is equipped with three RGB LEDs.
Two of the LEDs are used to light up the light well and are controlled by the same signals using transistors
as switches. The third LED is located near the color sensor and is used as auxiliary light for color
measurements.
Figure 29: LED schematic
6.9.2 Buttons
Nordic Thingy:91 has two buttons.
The main button, located underneath the Nordic Semiconductor logo, is termed as the SW3 button and it
is used for user input. It is connected to the nRF9160 SiP. The second button, termed as SW4, is connected
to the nRF52840 SoC. It is accessible only when the rubber cover on the device is removed. Refer the
image Figure 4: Inserting the SIM card on page 10 to locate the buttons.
Either of the two buttons, SW3 or SW4, can be used to activate the serial recovery mode of Nordic
Thingy:91 to update the nRF9160 SiP or the nRF52840 SoC respectively.
For more information, see the sections Updating application firmware on nRF9160 using USB (MCUboot)
on page 16 and Updating application firmware on nRF52840 using USB (MCUboot) on page 20.
6.10 Power supply
The main power source is a rechargeable lithium polymer (Li-Po) battery. The battery has a nominal
capacity of 1400 mAh and can be recharged through USB.
Nordic Thingy:91 has a power switch that physically disconnects the battery and the USB power from the
rest of the circuits. This switch must be on for Nordic Thingy:91 to work and charge the battery. When the
power switch is in the OFF position, it activates a circuit that drains the 1.8 V power domain.
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