After I had successfully built up a „Magnetic Levitation Object“ in conventional analog design and described that in article „Magnetic Levitation – The Easy Way“ , I now wanted to replace the technology of the 1980s with modern digital components. The object should also get a little smaller, and -as I hope – more beautiful.
Instead of the analog comparator, an ESP32 SoC module from M5Stack is now used. The ATOM LITE or also the ATOM MATRIX are extremely small (24mm*24mm*10mm or 15mm) and still offer all the appreciated features of the ESP32. So especially a quite fast 12Bit-ADC is available.
The Hall sensor A1302 is now operated with 3V3 so that the level is suitable for the ESP32 ADC. This is a bit below its data sheet specification, but works very well.
Furthermore a modified 5V relay is used as electromagnet – so no winding of coils etc is necessary and the result is predictable and reproducible. The modification of the relay is described in detail HERE. It can be controlled directly with 3V3 from the ESP32. As the former relais coil is now switched on/off very fast and has a high inductance, it is important to replace the diode D1 ( parallel to the coil) by an LED with a serial resistor. This limits the flyback voltage/current and preserves T1 against the resulting very high induction voltage. The three original connector pins (GND,+,S) are still used to connect the electromagnet.