D.L.—August 7, 2023
The media could not be loaded. This four inch touch screen showed great promise, but, unfortunately it failed to deliver for my use. I had several issues with this display, first, no documentation is included with the display, and there is minimal documentation available online from the manufacturer. Once I got it working, I found touch sensing performance was unreliable, no matter how many times I went through the calibration routines for the display. Inexpensive touch screen displays based on this chipset are numerous, in a variety of sizes, form factors and cost. What separates the good from the bad, in addition to hardware, is the quality of the software, libraries and documentation. I found the documentation of this display lacking. Very little useful information is provided. The libraries and support software are equally lacking, which results in subpar performance. This device is likely fine for a hobbyist, however, I found it unacceptable for my level of integration. This is a "resistance" touch screen, which means, unlike a modern smart phone or tablet, which use "capacitive touch", this is based on two layers of conductive film separated by some means (the type of separator varies by device). When you apply pressure it creates a connection between the two surfaces, which is resolved to a set of X and Y coordinates, which can be mapped by software. The problem is, this type of touch surface, if poorly implemented, is not very accurate. This is readily apparent when running the demo software. Even when using a precise stylus, there is a lot of noise, essentially errors in the touch detection. This results in button presses being ignored and often a press elsewhere on the screen will trigger the wrong button in the demo. The inconsistency of the touch sensor to provide accurate coordinates makes this unsuitable for my intended purpose as a "control interface". Speaking of pin-out, that is another issue with this board, as it is a "shield", meaning, it plugs directly into your Arduino. Normally a shield will have provisions for you to gain access to all the available pins of the microcontroller, unfortunately, that is not the case with this display. Once connected to your Arduino there is no way to access any available pins. This severally limits the usefulness of this display. It is fine if you have no need to interface to anything else, however, if you, like me, want to use this as an interface for a microcontroller connected to sensors and outputs, you are out of luck (unless you use cabling). The board connects to 13 Arduino pins (5 volt and ground plus digital pins D3-D13). So, what you end up with is, a low-resolution display with an even lower resolution touch sensor, with no easy way to interface it with anything else. I think this would be fine if this was priced as a "toy" or "learning device", however, at the time of my order, this cost more than the Arduino UnoR3 it was plugged into, which, considering the lack of useful information on interfacing, or any meaningful demo software, seems less than idea. As you can tell, I was disappointed with this board. I had planned on using it for a custom solar controller I have created, however, with the recommended libraries, it lacks both the touch resolution and stability to be useful to me. If you are a hobbyist, this may prove to be a fun toy to play with. If you are expecting this to match the quality and software support of genuine Arduino products, you likely will be disappointed. Based on all of this, I think 3 stars is a fair rating, as it does display and sense touch, but is lacking in documentation and software. Read more
