Yes Yes. I should stop making changes, but this time, I have a reason. Time Machine 1.0 did not really take into account the battery I was going to use. Adding a battery underneath increased thickness. The battery I was looking at was bigger than the board anyway. Things didn’t really make sense.
So here is Time Machine 2.0 (WIP – still routing):
In order to not make the same mistakes I’ve made before, I started Version 2.0 with something to model it after. Given the number of sensors and the LCD screen, I wasn’t going to model it after a Skagen or something exotic. Something more… nerdy.
Perfect. The classic Casio calculator watch. This thing measures about 42mm x 34mm x 9mm. It is fairly comfortable on my average sized wrist. The current design of the board will fit within these dimensions (including enclosure). Time Machine, however, trades sweet sweet algebra for other useful features like notifications and sensor fusion.
- 0.96″ OLED Color Screen with a 96×64 resolution.
- 240mAh 3.7V battery – Rechargeable via Micro USB.
- 120MHz STM32F2 with 1MB of flash and 128KB RAM.
- PAN1323 Bluetooth module capable of Bluetooth 2.0 with EDR, Bluetooth 4.0, Bluetooth BLE and ANT.
- MicroSD slot for MicroSD cards for various use cases such as data logging / application storage etc.
- MicroUSB (yay for standard connectors) for bootloader / data / charging etc.
- MPU-9150 9-axis awesome-o-meter
- 3-axis Accelerometer (upto +-16G at 1000Hz update rate)
- 3-axis Gyroscope (upto 2000 deg/sec at 8000Hz update rate)
- 3-axis Digital Compass (upto +- 1200uT)
- Barometer (50kPa to 150kPa)
- Temperature Sensor
- MEMs Microphone with amplifier
- Speaker (small, but should be fun to play with).
- Vibration motor
- TCS3472 Ambient color/light sensor
- Infrared transceiver
- Pulse oximetry sensor – this is basically an LED and a photodiode in close proximity.
- RGB notification LED
- 4 user buttons
- Debug / JTAG header for developers who don’t care to use the USB boot loader or just want to do some good ol’ printf debugging.
As with the previous version, this is meant to be for people who want to play with toys / sensors. In that spirit, I aim to make the software and hardware open. For starters, I’m thinking of making this compatible with the Maple IDE so users can easily write code for the watch. For other’s who are more comfortable with GCC and toolchains, I’ll work on a real SDK that works with an RTOS of some sort.
But exposition on the software front will have to wait for another post (partially because I still have to think about what I want to do exactly).