5 Round 2
Round 2 takes A and B (4) and gives them a brain. No ballast, the parts I have plus small bits like Wagos, an ESP32 running the fans on temperature, a little screen for temperatures and power, and lights inside.
| A2 Sled Tower | B2 Blade Tower | |
|---|---|---|
| Size, W × D × H | 142 × 171 × 287 mm | 158 × 132 × 190 mm |
| Boards | Flat on trays, jacks to the door | Portrait on blades, jacks up |
| Screen | In a control bay, seen through the door | In the base's front wall |
| Lights | Two strips in the tower's front corners | Two strips along the front, low and high |
| Air | Rear duct, a slot to each tray, out of the sides | Up between the blades, out of the top |
| Air channel per board | 2,540 mm², about 0.16 m/s | 1,490 mm², about 0.27 m/s |
| Push at the top to tip it | 4.6 N | 4.75 N |
| Mass, of which printed | 1.91 kg, 0.79 kg | 1.46 kg, 0.40 kg |
Both pass every check, with no ballast. The electronics are the same in both, so they get their own post (5.1), and each design has its own: A2 (5.2) and B2 (5.3).
What changed in both
- The fans answer to the temperature. Seven DS18B20 sensors (the intake, each board's exhaust and the power supply's chamber) feed an ESP32, which sets both blowers between 40 and 100%. If the ESP32 dies, the fans run flat out.
- Power on the front. An INA226 measures the whole 5 V feed, and a 2 inch LCD shows the watts, the amps, the temperatures and the fan speed.
- Lights. Two short WS2812B strips. Warm white by default, red if anything gets too hot, or one colour per board for its temperature.
- One more fuse. The fans' 1 A fuse becomes a 3 A fuse for the whole controller: fans, ESP32, screen and lights.
The power budget goes from 6.8 A to 7.5 A of the supply's 10 A.
Still open
- I need to measure the blowers, and buy the inlet, the LCD and the INA226, then check the models against them.
- The firmware has never run on real hardware.
- Neither design has its joints yet. That comes after I pick one.