ESP32 Cheap Yellow Display (CYD) Guide with a Jellyfish example

RE: ESP32 Cheap Yellow Display (CYD) Guide with a Jellyfish example

shabaz — Wed, 01 Apr 2026 15:04:05 GMT

The menu is slowly coming along..

There are just three types of things to tap on:

(a) plain buttons,
(b) buttons with a built-in value display, and
(c) buttons with on/off slider.

All the above can be individually dimmed as required, if (say) if an admin password is not entered.

For almost zero additional code, the menu code is reused to provide "MsgBox"- type functionality (see Status in the video) by simply removing the Cancel button.

Poor quality handheld video:

[View:https://www.youtube.com/shorts/JmIlt-163i0:640:360]

Another option could be to use LVGL, which apparently "ESPHome" uses, and then menus can be created with config files (I believe). It might be more heavyweight in terms of resource consumption though.

RE: ESP32 Cheap Yellow Display (CYD) Guide with a Jellyfish example

shabaz — Mon, 30 Mar 2026 16:36:06 GMT

Despite planning to rely on BLE for config, I realized that a minimal on-screen menu might be occasionally helpful for projects, for instance, to switch BLE on or off, or to enter a passkey to enable BLE or whatever.

I'm sure menu systems must exist for the CYD, but I figured it would be worth starting from scratch, to ensure very little Flash and RAM is required, and to try to keep it very general, for flexibility.

This uses C arrays, for storing each menu detail. There is a class called MenuSystem, with a displayMenu method, e.g.

menu.displayMenu(MENU_TOP, "-") would show the following:

So, if the user was to (say) press on the PWM button, then menu.displayMenu(MENU_PWM, "-") would be called (the "-" can be replaced with a default value so the user can see what's currently configured). And no backspace, just cancel to keep the code simple.

(The minus button shouldn't be there, that was a mistake in the array of button names for that particular menu).

The code allows up to 12 arbitrary buttons per menu, which is just enough for numeric, but of course insufficient for full text extry (I think that would be tedious to enter on such a small screen anyway, so it would be better to just use the BLE menu option, then do the rest on the mobile phone.

Once this is working I'll put it on GitHub.

RE: ESP32 Cheap Yellow Display (CYD) Guide with a Jellyfish example

kmikemoo — Mon, 30 Mar 2026 00:37:28 GMT

[mention:b0bc65b9ecdc4307bd967592f00e340a:e9ed411860ed4f2ba0265705b8793d05] Thank you for the detailed instructions. I also appreciate the insight on hackaday. I was thinking that I just didn't know how to use the site correctly.

RE: ESP32 Cheap Yellow Display (CYD) Guide with a Jellyfish example

DAB — Sun, 29 Mar 2026 19:19:09 GMT

Nice post.

Interesting little display.