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On the weekend of 22.4./23.4. I created my first prototype for the cube interior and the 3D printed case.
I used a BME280, MPU6500, SSD1306 Oled, ADPS9900 and VL53L1X for my first prototype. It worked amazingly good and was simple to test with micropython. Soldered all sensors together on their I²C pins. First had trouble installing MicroPython on the ESP32, because I didn't use the ESP32-C3 USB-Version.
The case I designed with FreeCAD. The rounding corners where quite time consuming...
Now I'm waiting for the PCB and all the ordered parts.
The v0.1 of the ESP32-C3 PCB I ordered on 17.4. on pcbway.com. I think their are some flaws, that's why I'm already on v0.2 and hope to also order these revision as soon as possible. The PCB has two layers.
The PCB v0.1 I ordered without a stencil and this was impossible to solder as 0402 is really tiny... With the stencil for PCB v0.2 I needed three attempts - I have no professional frame and improvised by using a credit card to move the solder paste. For the heating plate I used a manual switch for regulating the temperature -- not so ideal but it worked.
The PCB from PCBWay is 1.6mm thick. I reordered the v0.2 with 1mm thickness at JLCPCB (want to compare with PCBWay).
Case design I did with FreeCAD. See "case" directory for CAD- and stl-files.
The parts I ordered mainly from AliExpress. Total costs for parts ~35$.
| Part | Price [$] |
|---|---|
| ESP32-C3 Board | 10.00 |
| Gyro sensor MPU 9250 | 5.99 |
| Voltage/Current sensor INA219 | 0.94 |
| Temperature/pressure/humidity sensor BME280 (3.3V) | 2.32 |
| Time of Flight sensor VL53L1X | 4.65 |
| Microphone | 1.38 |
| Light Sensor VEML7700 | 2.15 |
| 30x25mm solar cell (1V/80mA) | 0.30 |
| LiPo Battery 300mAh/3.7V | 0.79 |
| OLED 0.96 inch, SSD1306 | 1.24 |
| RGB LED WS2812 2x2mm | 0.08 |
| 12mm self-locking on/off button | 1.20 |
| Tactile Push button 6x6x5 | 0.02 |
| JST 3-Pin Connectors | 0.24 |
| 14-Pin Header | 0.10 |
| 2 Female Banana connectors | 0.68 |
| Double sided tape | 1.99 |
| Mounting Nut M2.5 | 0.03 |
| M1.6 Screws 10mm | 0.09 |
| 36AWG Wire | 0.25 |
| 26AWG Wire | 0.25 |
| PLA | 0.30 |
For programming I use MicroPython as I'm used to it and I like it 😄. For flashing the firmware Thonny is super useful and I also recommend it for programming the ESP32.
The driver files for the sensors can be found in the "software" folder.
The first full prototype I made on 14.05.23. The soldering of all the parts was tedious as all the sensor needed to cables per connector hole. The case came out pretty good with the green filament. Putting together the cube was not possible as the sensors with cables needed to much space. So I'm planning on creating a 45x45x45mm cube. The smaller case I will adapt for a "Lite" version of the cube with a INA219, BMP280 and BH1750 sensor only.
So now I need to design a bigger case...