A few weeks ago, I got to know a wonderful modern art of drawing golden fish in super clear epoxy glue, which is invented by a Japanese artist, Riusuke Fukahori. It really looks like a living real fish but it is a drawing on epoxy. Unfortunately I am not artist nor drawing well but can make circuit. Why not put circuit in epoxy?
My personal basic rule of this project.
(1) It should be reprogrammable.
(2) It should be battery less, from viewpoint of safety and long life operation.
(3) As much as possible, it should be interesting and fun.
This time, I made more simple object just for joy. the above picture shows the object buried inside epoxy resin. Indeed they are object for N-gauge model train, and I added several tiny (1005 (0403)) size LEDs for headlight of car, traffic signals. Just turning on is not so interesting, so I put Arduino boot loader loaded ATmega328 below the basement of traffic signal. I made it looks like the car is ready to fly!!
And here is the completed one. Signal is controlled by MCU and actual operation can be found in the following movie... Have fun!
Here I made a short demo movie. All of firmware is uploaded through OTA (over the air), The case of nRF, firmware uploading is quite safe because boot loader and application are separated in memory, but the case of ESP32, the OTA code and user code are mixed up in the program and it's very, very easy to make it BRICK (lose control, turns into static object..)
The function, "ArduinoOTA.handle()" must be kept in running in loop function but blinking LED (especially delay() function) will interrupt its operation. Once this code is uploaded through OTA, it will "brick" the module and we need wired firmware uploading (but in the epoxy, no way.)
The correct way is, (not the only way, just example)
This encounter was almost "groundbreaking" to me, but unfortunately I am not good at drawing but I want something inspired by this wonderful shock.
Actually I did not know the existence of this material "super clear epoxy". As you see, it is really clear and looks like floating inside transparent object. Currently it is just the beginning but I will try make more by using this wonderful material. On the next project log, I will explain how to program them (as you guess, it's OTA)..
What kind of material is this "super clear epoxy"??
It's a "Crystal Resin Neo" made by Nissin Resin in Japan. The point of this resin is, "super tolerance for turning yellow". It seems, general epoxy resin turns into yellow after a certain period time but this resin has a tolerance for it (keeping it crystal clear). Similar items (I am not sure their quality but) also can be found in Amazon and we can try as we wish!