HiLetgo 1602 LCD Keypad Shield 1602 LCD Expansion Shield Board Blue Backlight 4.5-5.5V for Arduino Duemilanove Robot

Different vendors have provided me with these modules. So far, all of them have worked reliably, including this one, but they are all flawed in one major way. In order to control the backlight led, a transistor is used. It is clear that the circuit was designed to use a MOSFET, but every vendor substituted a bipolar transistor. From the base to the supply, a pull-up resistor is present, but from the board pin to the supply there is no resistor. In this case, the high from the output is applied directly to the base of the NPN transistor, with the emitter being A short circuit is pretty much what that pin is doing. It is possible to work around the problem in two ways. On that pin, either output a low or never a high. Pull it all the way low (with the backlight off) or put it in input mode (with the backlight on) or add your own transistor with a resistor in series. There is a hassle involved in making that as you need to cut the trace to the pin and solder the resistor to it. If the board has a resistor in series with the base, it would be best to do so or to mount a MOSFET, but the resistor needs to be behind the existing pull-up Both the current pull up and the transistor are located directly underneath the LCD module, which is not easy to desolder due to the many pins in the tightly There is a great deal of brightness in the backlight, so this should be controlled by Certainly a hardware modification is needed or you will could overload that Arduino pin that's always in output mode and it may blow up. The modules have also been used with a WEMOS ESP8266 chip. Although the board sees 3V as a valid high level, those output 3V but it works just fine. There is an additional modification needed to limit the input to 3 V by adding an 8k2 resistor to ground from A0. However, it does not leave a lot of I/O on the board for you to use. This can be achieved by adjusting the analog values of the switch.

Emerie Compton

| Sep 10, 2020

All of the buttons (except Reset) are connected directly to the AO by resistors. Based on an APPROXIMATE reading, these are the readings The following options are available
720
Left Then scroll down Up to 305
Right 130
.

Mylo Bird

| May 06, 2021

The LCD keypad shield I purchased was the cheapest that could be shipped without a ton of shipping time. It failed to work upon receipt. When I tested it thoroughly, I confirmed that the buttons worked and that the backlight worked, however, the text did not appear. It is likely that the culprit was something related to that component, as the contrast dial did not help. Since the military soldiers were messy, I identified poor quality control as the probable cause of the problem. Please heed the warnings on this story. By inserting a resistor between two of the pins on the contrast dial, I was able to resolve this issue. My resistor was selected after a series of trials and errors. My wire got hot when I used it, so I used a random-choice resistor rather than bare wire because I became concerned about it scorching. It was not just me who had no clue what I was doing. Whoever put the site together didn't know either.

Marcus McIntosh

| Mar 22, 2021

To use it in a project, I need it to stack but I cannot because it has too short pins compared with other shields available. The circuit apparently does not have a resistor as per their website documentation. This leads to the board shorting out when the backlight pin is set to "high" and either you crash the board or something else blows up. However, the good news is that you can work around the problem by cutting off pin 10 and soldering a diode jumper plug from pin 10 to pin 3, which allows proper backlight functionality (high is on, low is off) without shorting the battery.

Quinn Hoffman

| Apr 19, 2021

I expect that it will fit both the Arduino Uno and recommend using it in a Mega, as you will have more pins to choose from. There is a dimness to the pictures sorry for any inconvenience You can imagine how bright it can be!.

Trevor Pacheco

| Feb 18, 2021

There's nothing to dislike here about this LCD/keypad shield, which is a great deal for those casual projects and not meant to be used extensively. While key switches seem to have slightly more noise than most of the other shields I've used (Cytron, DFR, etc. ), your standard debounce code will be able to handle the noise. As of June 2005, the ladder voltages on keypads appear to be slightly lower than on the reference design (ADC count general, I recommend it.

Leighton Craig

| Mar 09, 2021

You should either check the D1Robot reviews for the pinout if you haven't already done so. Those who want to use the program will need to copy a sketch. You may adjust the "pot" for contrast, but bear in mind that this style of pot requires a lot of turns to reach It is possible to solder additional headers to the holes so you can utilize the pins that are not being used. In my case, the display is mounted horizontally and uno is mounted on standoffs. Mounting the display is done through a cutout.
There may have been a solder problem, so if you are concerned, you may want to try.

Kye Waller

| Feb 16, 2021

This shield is fully compatible with the Uno. With everything already set up, it enables you to connect a LCD easily. I have to make sure that the pins on IDE are changed because it's wired differently from a standard 1602 LCD. You can find the pinout in the description. To see the pinout, you'll need to look at a picture. It is ideal for setting the screen contrast to suit with the on board potentiometer
Definitely recommend it.

Elisa Guerra

| Feb 04, 2021