Teardown Tuesday: Budget Smartwatch

Today many smartwatches can cost hundreds of dollars, but others can be purchased for relatively cheap.

In this Teardown Tuesday, we're going to take a look at the insides of a low cost (<$30 USD) smartwatch. This particular watch is by Otium and is their “One” model.

 

The Otium One Smartwatch 

 

This smart watch features a removable battery, a cellular radio, a front-facing camera, and a microSD card slot. Opening up this watch was relatively easy. Four Phillip's screws underneath the back panel secure everything together.

 

The Smartwatch with the Back Panel Removed 

 

Battery

The User-Changeable Lithium Battery

 

This smartwatch uses a single cell Lithium battery that is marked at 350mAh. Below is an image of the battery pack. On the battery, there is a label indicating the "Rate[d] Capacity", “Nominal Voltage”, the “Limited[Peak] Voltage”, conformity indications and warnings. The cell appears to have been manufactured by Jinke Energy on December 26th, 2015.

 

The Bare Lithium Cell Without the Protection PCB and Label 

 

Attached to the battery cell is a small protection circuit. This small circuit board most likely provided short circuit and over discharge protection for the cell.

 

The Battery Protection PCB 

Display

The Pixels on the Watch's Display 

 

This smartwatch contains an LCD display that has a resolution of 240x240 pixels. The display is laminated to the face of the smartwatch. This smartwatch has a capacitive touch screen. Interpreting the inputs is a FocalTech FT6236, this touch panel controller is designed for displays smaller than 4” according to the manufacturer. The IC supports 2 finger multi-touch and communicates over I2C. The data sheet can be found here.

 

The Touch Screen Controller 

 

The display panel and the capacitive sensor are laminated together in a method called a “One Glass Solution”. The OGS is designed to reduce the thickness of displays. The OGS stack is then laminated to the face of the watch. Due to this construction method, it is often very difficult to repair and replace. 

 

 

The Part Number for the LCD Display 

 

To provide the illumination to the display, there are three surface mount LED lights.

 

The Backlight LED's 

 

System on a Chip

At the heart of the smartwatch is a MediaTek MT6261. Not a lot of information was available online about this SOC (System on a Chip). Although it seems that a lot of lower end feature phones and other budget smart watches run this processor.

 

The MediaTek MT6261 SOC  

 

Paired with the processor is a 64M-bit Flash memory IC, the KH25U6439F made by Macronix.

 

The Flash Memory IC 

Other Stuff!

Unpopulated Parts

The small circuit board is most likely used in many different low-cost smartwatches, as a result, there were many unpopulated component footprints on it.

 

Many of the Unpopulated Pads 

Unidentified Parts 

There were two compact SMD IC’s that were unable to be identified. They were most likely a Bluetooth IC and an accelerometer used for the pedometer and motion detection in the watch.

 

Unidentified IC.  Possibly An Accelerometer  

 

Unidentified IC. Possibly A Bluetooth IC 

Camera 

This smart watch has a small front-facing camera. The camera module was 5.2mm across and 2.9mm thick.

 

The Very Tiny Camera  

 

Cellular Connection

The RDA Amplifier 

 

In addition to having a Bluetooth connection, this smartwatch also has a 2G cellular connection for sending text messages or making phone calls. These features do require an activated sim card. To amplify the cellular transmissions, an RF front end is used, an RDA6625 IC made by RDA. This IC contains amplifiers for 800Mhz, 900Mhz, 1800Mhz, and 1900Mhz according to the manufacturer. The antenna connects to the circuit board through a small co-axial connector. This appears to be a W.FL connector, which is a smaller variant of the U.FL connector that is fairly popular.

 

The Antenna Connector 

 

The cellular antenna is mounted in the wristband of the watch. The antenna was firmly buried inside of the watch band after a fair amount of struggling the antenna could be pulled out.

 

The Antenna Removed From the Band 

 

Wrapping it Up! 

For less than $30, there's a fair amount of tech packed inside of this small package. A few red flags can be brought up about this smartwatch, such as a lack of an FCC ID number, minimal documentation, and this Amazon's reviewer's claim that the device caught on fire!

Thanks for looking at this week's Teardown Tuesday.

Stop by next Tuesday for another teardown! We're always looking for new things to teardown, if you have any suggestions or would like to contribute an item for a future Teardown Tuesday click here for my email address.

Next Teardown: IoT Garage Door Opener