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Using DUO Digital Stethoscope + ECG


  1. Eko DUO
  2. DUO earpiece
  3. Wireless touch charging pad
  4. 5W / 2A USB Power Adaptor
  5. Micro USB to USB cable
  6. Getting Started instruction card

Device Overview


Power ON

Press and hold down the center button for 2 seconds to power on your DUO. Once the device is on, you will see a ring of lights briefly circling around the button and then a blinking white light. Your device is now ready to pair with the Eko App and be used to listen to sounds, capture ECG signals, and take recordings.

Power OFF

To power off, press and hold down the center button for 2 seconds. You will see a ring of lights briefly, and Once the device is off, the LED lights will disappear. 

Standby Mode

The DUO has a 5 minute standby mode to conserve battery life. The white light will disappear when the DUO goes into standby mode. To power the device back ON, hold the center button briefly. You will see a ring of lights white blinking lights. 

Charge the DUO


The DUO must be properly placed on the wireless charging pad in order to charge.

First, connect the charging pad to the power source using the included USB charging cable and power adaptor. You will notice an orange blinking light at the top of the charging pad once it is plugged in, which will change to a steady white light when the pad is ready to charge your DUO..

Place your DUO on the charging pad with the center button up and the diaphragm and electrodes down. You will immediately see the DUO’s LED lights flash and circle around the center button. This is signaling that the device is charging. When fully charged, the lights will stop flashing and the LED on the charging pad will turn off.

To fully charge the battery, it should take about 45 minutes. When fully charged, the DUO should last for about 9 hours of continuous use. We recommend turning the DUO OFF between each use to maximize battery life.

Note: The DUO will not connect to the Eko app while charging.

Clean the DUO Device 

Eko recommends that DUOs be cleaned using 70% isopropyl alcohol wipes or solution. Note: DO NOT immerse the device in any liquid or subject it to any high-pressure/autoclave sterilization processes.

Ensure the best audio quality with DUO

Minimize movement 

  • The DUO is sensitive to vibration and hand noise. 
  • Use the DUO directly on the skin. 
  • Apply firm pressure, being careful not to turn the device off accidentally by pressing the center button. It may be helpful to hold the DUO in your palm and press against the patient so that there is equal pressure applied.

Minimize environmental noise

  • While the DUO is designed to gather sound when the diaphragm is placed directly on your skin, it may still gather environmental noise especially if used in a loud environment. Eko therefore recommends that users seek a quieter area to conduct their listening and analysis. 
  • Ensure that no other objects are making contact with the Eko DUO.  

How to ensure best ECG signal quality:

The ECG signal quality indicator (see Figure) will appear at the bottom of the mobile device screen when a DUO is connected. If you are not reaching the “high quality zone” with your ECG signal, see the recommendations below for optimizing ECG quality. In addition, you can always access these tooltips by clicking directly on the ECG signal quality indicator.


Use DUO directly on the skin

  • If both metal leads are not in contact with the skin, then the DUO cannot capture an ECG. For example, sometimes a person’s chest is more contoured, which can make it difficult to lay the DUO flat on the chest. Sometimes you can overcome this challenge by holding the DUO in different orientations (vertically, horizontally, angled) across the patient’s chest in order to attain better contact with the skin and to capture the best ECG signal. 

 Apply firm pressure. Exact location varies, see image below for details.

  • The DUO is sensitive to vibration and hand noise. Gripping the DUO tightly and pressing it firmly against the skin, while keeping your hand as still as possible is essential to collecting clean signals. Some users have found that “palming” the DUO helps achieve these goals.
  • Apply firm pressure against the chest to ensure good ECG electrodes contact. Use constant pressure to make sure the connection between the skin and the electrodes stays tight. Be careful not to accidentally press the center button, which may turn the DUO off!

Placement for Heart Sounds:  Use the guide below to position the DUO on the chest for optimal heart and lung sounds. 

Placement for Lung Sounds: 

For self-application, you can only listen from the front of the chest.  If you have an assistant, you can listen to the back of the chest by following the placement guide below for back placement.



Avoid nearby AC power sources

  • The DUO may pick up noise from nearby power sources (e.g. wall outlets). All ECG leads (even typical 12 lead ECGs) are affected by electromagnetic fields generated by 50-60Hz power sources. Position the DUO as far away from wall outlets and other power sources as you can.

Manage thick chest hair, dry skin, or body fat.

  • Although Eko has not tested each of these tips itself, users have reported to us that these maneuvers may help:
  • Shave the chest if hair is potentially obstructing contact with the skin.
  • Apply water, saline, contact lens solution, or ECG gel to the skin in order to improve conductivity. (Do not apply these solutions directly on the DUO.)
    • Individuals with dry skin may be most in need of having additional solutions applied to their skin.
    • Lotion is not an appropriate alternative to water, saline, or ECG gel. Properties in lotion may impede the signal; do not apply lotions to the DUO

Maintain close proximity between the DUO and the Eko app (within 5 feet) to ensure a good Bluetooth connection

DUO Bluetooth Pairing with the Eko App


  1. Enable Bluetooth on your selected mobile device. 
    1. On iOS devices, go to Settings > Bluetooth, and tap the slider to turn Bluetooth ON. 
    2. On Android devices, go to Settings > Connections, and tap the slider next to “Bluetooth” to turn Bluetooth On.
  2. Turn on your DUO by pressing and holding the center button until you see the lights flash around the ring once. A single LED should now be flashing white.
  3. Open the Eko mobile app and log in
  4. On the app, click “Connect Device”
  5. Select the DUO device on the screen and your DUO and phone will be paired
    1. On Android devices, you may see a “Pairing Request” message pop up. Click on “Allow” and your DUO will be paired.
  1. If Bluetooth pairing is unsuccessful, an error message will appear in the App and no sounds will be recorded. Please visit our troubleshooting section if you are unable to connect the DUO to your mobile device

Unable to Charge DUO

Ensure that the light on the charging pad is on. The light will be white if the DUO is not placed on the charger and orange when the DUO is placed on it and is charging. If you do not see any light, please check the following:

  1. Ensure that the micro-USB cable is securely plugged into the charging pad and that the cable is connected to a powered USB port (5v maximum).
  2. If no light appears, please try a different cable and wall plug 

If your charging pad is not lighting up after trying a different cable and power plug, please click here to submit a replacement request. 

Once the charging pad light is on, place the DUO on the charging pad so that the power button is facing upwards. You should see a ring of lights illuminate on the DUO once it is placed on the charger to indicate that it is charging. If you do not see this, please leave the DUO on the charging pad overnight. 

If you are still experiencing issues with charging, please click here to submit a replacement request. 

LBL 219, Rev A, April 28, 2021



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