Wiring a screen demo board can be a bothersome task. The inexpensive ones may have poor documentation, and some even have mislabeled pins. Keeping a drawing up to date helps immensely, especially when building multiple prototypes. The second issue was ensuring everything was wired correctly. The tagger screen had six control wires and two power conductors, so it would have been easy to get a couple of wires reversed or a poor solder joint. Despite the trouble, having a screen is worth the effort.
I uploaded a demo sketch for the ESP32 and ST7735 screen controller, but it only boot-looped. This error likely indicated that my sketch was not compatible with the firmware of my microcontroller board, but it confirmed that my upload settings were correct. I found another example from Adafruit, which still caused boot looping, but the sketch made more sense than the first, so I made some changes. The boot-looping stopped, but I could not see anything on the screen.
Sometimes the issue is that the screen shows something, but unless the backlight is on, it is almost impossible to see. I pivoted my attention to the backlight, which I wired to an output pin. I wrote a program to toggle the IO pin high and low, but that failed. I rechecked the screen, and I could faintly see the graphics. I shone a bright flashlight toward the screen to take a photo of the screen inverting, as indicated by the demo program.
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Completed projects from year 7
Completed projects from year 8
Completed projects from year 9
Completed projects from year 10
Completed projects from year 11
Completed projects from year 12
Disclaimer for http://24hourengineer.blogspot.com and 24HourEngineer.com
This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.
All information on this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property, or similar, is the responsibility of those involved in the replication.
All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.
Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.
This blog, including pictures and text, is copyright to Brian McEvoy.
2025-07-26
I uploaded a demo sketch for the ESP32 and ST7735 screen controller, but it only boot-looped. This error likely indicated that my sketch was not compatible with the firmware of my microcontroller board, but it confirmed that my upload settings were correct. I found another example from Adafruit, which still caused boot looping, but the sketch made more sense than the first, so I made some changes. The boot-looping stopped, but I could not see anything on the screen.
Sometimes the issue is that the screen shows something, but unless the backlight is on, it is almost impossible to see. I pivoted my attention to the backlight, which I wired to an output pin. I wrote a program to toggle the IO pin high and low, but that failed. I rechecked the screen, and I could faintly see the graphics. I shone a bright flashlight toward the screen to take a photo of the screen inverting, as indicated by the demo program.
 |
| Showing the changing screen |
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Completed projects from year 7
Completed projects from year 8
Completed projects from year 9
Completed projects from year 10
Completed projects from year 11
Completed projects from year 12
Disclaimer for http://24hourengineer.blogspot.com and 24HourEngineer.com
This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.
All information on this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property, or similar, is the responsibility of those involved in the replication.
All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.
Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.
This blog, including pictures and text, is copyright to Brian McEvoy.
2025-07-26
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