154 lines
7.8 KiB
Markdown
154 lines
7.8 KiB
Markdown
# W800_Smart_Watch
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## Why this project :
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I was interested in working on a bigger project with more challenges and which could be useful.
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I am also quite unhappy with the smartwatches that are on the market (expensive, no access to the firmware, data collection and privacy issues), that's why I decided to try doing my own that I can fully customize. This is going to be a long adventure with a lot of discoveries along the way :).
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I also wanted to test this W800 SOC more deeply and see what it could do and I think it is a perfect fit for the project.
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So let's go !
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## A Smart Watch project using the Chinese W800 SOC.
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The W800 is a pretty interesting chip with impressive characteristics for its price (around 1$) :
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### Core :
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* 32bit XT804 CPU
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* 240 Mhz frequency
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### Memory :
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* 2 MB on chip flash
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* 288 KB RAM
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### Wireless connectivity :
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* Bluetooth EDR(Classic) and BLE 4.2
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* WiFi 2.4Ghz 802.11 b/g/n
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## Sensors :
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The goal is to embed the following sensors in the watch :
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* An accelerometer (for wrist tilt detection, single and double tap detection , foot step counting and more)
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Possible choices :
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* ADXL345
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* MPU6050
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* BMI160
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* LSM6DS3
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* BMA456 <-- **SELECTED** i2c addr : 0x18 or 0x19 7 bit address, has the wrist tilt detection feature.
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* A magnetometer (possible choices):
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* HMC5883L <-- After reading some comparison articles between the HMC5883L and QMC5883L and the datasheets, the later seems better in term of perfomances.
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* QMC5883L <-- **SELECTED** i2c addr : 0x0D 7 bit address, better soldering footprint
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* LSM303DLHC
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* BMM150 <-- Package with balls, hard to solder
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* An air pressure/temperature sensor (to display the altitude for example)
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* BMP280 <-- **SELECTED** i2c addr : 0x76 or 0x77
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## Actuators :
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* A vibration motor to notify events to the user.
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* ~~A piezo buzzer~~ : dropped, maybe in next version.
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## Power source :
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* 1 cell lipo 450 mAh battery.
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* A charge/discharge controller.
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## Screen + touch element :
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* [Screen with touch](https://fr.aliexpress.com/item/1005004887834918.html?spm=a2g0o.order_list.order_list_main.22.340a5e5bX8WCb0&gatewayAdapt=glo2fra) : GC9A01 with touch panel. It uses the required 4 line Serial Interface.
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* Touch element i2c addr : 0x15, CST816D I2C touch driver.
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## Programming and charging :
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* The smart watch programming and charging is done through the same USB port
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using a magnetic 4 pin plug.
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## MCU Pin assignement table :
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| Pin Number | Pin Name | Type | Function | Pull UP/DOWN| Connected to | Comment |
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|------------|----------|------|----------|-------------|--------------|---------|
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||PB_20|I/O|**UART0_RX**/PWM1/UART1_CTS/I²C_SCL|U/D|**USB/Serial TX flash pin**||
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||PB_19|I/O|**UART0_TX**/PWM0/UART1_RTS/**I²C_SDA**|U/D|**USB/Serial RX flash pin** and **BMA456, Touch Panel, HMC5883L and BMP280 SDA pins**||
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||WAKEUP|I|**External Wake Up Pin**|D|**BMA456 IRQ line** and **Touch Panel IRQ line** through NAND Gate|The chip is waken up when the pin is HIGH|
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||RESET|I|Reset Pin|D|**Micro switch** and **USB/Serial RTS pin**||
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||XTAL_OUT|O|External crystal output||||
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||XTAL_IN|I|External crystal input||||
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||AVDD3V3|P|Chip power supply, 3.3V||||
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||ANT|I/O|RF Antenna||||
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||AVDD3V3|P|Chip power supply, 3.3V||||
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||AVDD3V3|P|Chip power supply, 3.3V|||
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||AVDD3V3_AUX|P|Chip power supply, 3.3V||||
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||TEST|I|Test function configuration pin||||
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||BOOTMODE|**I/O**|BOOTMODE and I²S_MCLK/LSPI_CS/PWM2/I²S_DO|U/D|**Touch Panel Reset line**||
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||PA_1|I/O|JTAG_CK/**I²C_SCL**/PWM3/I²S_LRCK/ADC0|U/D|**BMA456, Touch Panel, HMC5883L and BMP280 SCL pins**||
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||PA_4|I/O|JTAG_SWO/I²C_SDA/PWM4/I²S_BCK/**ADC1**|U/D|**Battery resistor voltage divider output**||
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||PA_7|I/O|**PWM4**/LSPI_MOSI/I²S_MCK/I²S_DI/Touch0|U/D|**LCD backlight N-MOSFET driver**||
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||VDD3V3IO|P|IO power supply, 3.3V||||
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||PB_0|I/O|**PWM0**/LSPI_MISO/UART3_TX/PSRAM_CK/Touch3|U/D|**Vibration motor control pin**||
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||PB_1|**I/O**|PWM1/LSPI_CK/UART3_RX/PSRAM_CS/Touch4|U/D|**Touch Panel IRQ line**||
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||PB_2|I/O|PWM2/LSPI_CK/**UART2_TX**/PSRAM_D0/Touch5|U/D|**Debug UART serial output**||
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||PB_3|**I/O**|PWM3/LSPI_MISO/UART2_RX/PSRAM_D1/Touch6|U/D|**TP4056A Charging Signal**||
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||PB_4|**I/O**|LSPI_CS/UART2_RTS/UART4_TX/PSRAM_D2/Touch7|U/D|**TP4056A Charged Signal**||
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||PB_5|**I/O**|LSPI_MOSI/UART2_CTS/UART4_RX/PSRAM_D3/Touch8|U/D|**Battery resistor voltage divider enable**||
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||VDD3V3IO|P|IO power supply, 3.3V||||
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||CAP|I|External capacitor, 4.7µF||||
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||PB_6|I/O|UART1_TX/**MMC_CLK**/HSPI_CK/SDIO_CK/Touch9|U/D|**LCD Serial Clock Pin**||
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||PB_7|I/O|UART1_RX/**MMC_CMD**/HSPI_INT/SDIO_CMD/Touch10|U/D|**LCD Serial Data Pin**||
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||PB_8|**I/O**|I²S_BCK/MMC_D0/PWM_BREAK/SDIO_D0/Touch11|U/D|**LCD Data or Command Selection Pin**||
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||PB_9|**I/O**|I²S_LRCK/MMC_D1/HSPI_CS/SDIO_D1/Touch12|U/D|**LCD Reset Pin**||
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||PB_10|**I/O**|I²S_DI/MMC_D2/HSPI_DI/SDIO_D2|U/D|**LCD Chip Select Pin**||
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||VDD3V3IO|P|IO power supply, 3.3V||||
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||PB_11|**I/O**|I²S_DO/MMC_D3/HSPI_DO/SDIO_D3|U/D|**BMA456 IRQ 2 line**||
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||GND|P|Ground (Central Pad)||||
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## What is done/working so far :
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* LVGL 8.3.3 running on the SOC using DMA.
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* Supported LCD drivers :
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* ILI9341 in 4-line serial mode (8 bits) with D/C pin
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* ST7789 in 4-line serial mode (8 bits) with D/C pin
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* GC9A01 in 4-line serial mode (8 bits) with D/C pin
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* Supported LCD touch screen :
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* CST816D capacitive touch ic.
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* Three screens designed and working with LVGL :
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* 1 watch face based on a casio watch.
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* 1 menu list screen with icons.
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* 1 setting screen with basic settings (date and time + display brightness) (work in progress).
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* Debug UART on PB_2 (output only)
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* Wake up interrupts handling :
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* Wrist tilt MCU wake up working
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* LCD touch wake up
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* Sensors/Actuators :
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* QMC5883L driver working
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* BMA456 driver working
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* BMP280 driver working (temperature + pressure)
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* Battery voltage sense using ADC is working
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* Vibration motor controlled by PWM working
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## To do :
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* Write I2C drivers for the :
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* [X] BMA456
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* [X] Wrist tilt detection
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* [X] BMP280
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* [X] Temperature
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* [X] Pressure
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* [X] QMC5883L
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* [X] Write the init sequence for the GC9A01 LCD driver.
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* [X] Make LCD display + touch work.
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* [X] Design and test battery voltage sensing circuit -> voltage divider bridge because ADC input can sense 2.5V Max.
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* [ ] Finish to design the settings page.
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* [ ] Implement a good algorithm to handle adaptiv MCU clock to save power
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* [X] Test the charge circuit.
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* [X] Handle watch auto sleep feature with wake up on screen touch + wrist tilt (POC could be improved).
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* Design and test the :
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* [X] vibration motor circuit
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* [X] Draw the schematic, the first revision of the schematic is available [here](design/Kicad/W800_Smart_Watch/W800_Smart_Watch.pdf).
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* [X] Design the PCB (routing, placement etc..) on a 2 layer PCB - done.
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* [ ] Update the W800 SDK from version 1.00.08 to version 1.00.10 released in January of 2023.
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## Achieved power consumption recap:
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(Need to work on sleep current :-( )
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| Mode | Current draw | Estimated battery life (450 mAh lipo) |
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|--------------------------|--------------|---------------------------------------|
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|Active (40Mhz clk)<br>(No BLE / No WiFi) |~52 mA | ~8 hour |
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|Active (240Mhz clk)<br>(No BLE / No WiFi) |~72 mA | ~6 hour |
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|Sleep |~4.5 mA |~4 days and 4 hours |
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|Standby |~1.8 mA |~10 days and 15 hours |
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## Some screenshots of the achieved visuals currently running on the watch using lvgl :
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## Here is a preview of what the PCB should look like :
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### The front :
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### The back :
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