Supply Voltage to 2.4" Display

Hacking
1

Sorry for all of the questions, I have had the displays for a long time but just retired and starting to play with them.

I have added a 2.4" display to a SonOff 4 Channel Pro that has a Uart that provides 3.3 volts ttl and vcc, I have tried the displayed powered form 3.3 vdc and do not see any difference than when powered from 5 vdc. Does anybody know of a problem that the 3.3 supply would cause for the display. To supply 5 vdc I can add a 5 vdc regulator inside the case I need to.

2

The other LCDs I use are powered via USB, which should be 5V.
Maybe you can ask their after-sales for this question.

3

The 4 channel pro has two power inputs one is dc and I feed it with 12 vdc and it drops it down to 3.3 vdc. The other choice is 110 vac that feed an internal transformer, rectifier and regulator to supply 3.3 vdc.

I have been running the display on 3.3 vdc for about 5 days without any problems (so far).

In another post I notice on the mcu chip that are used in at least the basic models the operating voltage was 2.4 to 3.6 vdc for the processor.

If I need to I will add a 5 volt regulator to the connector that has the 12 vdc wall wart plug into it.

Thanks for the response.

4

Hi,

Supply usually is 5v.
Signaling is 3.3v.

Having that said,
The only care you must to keep is:
Not inputing control signal more than 3.3v or it will stop working.
Bear in mind that 3.3v signal from Nextion TX IS usually within limits for 5v logic so, you only need to “adapt” the RX.

It’s done really easily by placing a SERIAL resistor 1k from your controling module to Nextion RX, AND… A paralel resistor 2k2 from Nextion RX to GND.
This voltage divider shows about 3.4…3.6v on RX pin when 5v appiled so, it’s within the signal voltage margins to work whit no problems at all and no demages to Nextion.

I hope this helps.

Note:
If you power the Nextion with 3.3v you may notice brightness diference but not really big when used “indoor”.

5

Thanks, I have been using 3.3vdc for about a week with no ill effect, brightness is good enough that I can see it outside in direct sunlight here in Florida (when it is not raining, got 5 inches in 2 hours yesterday). I will add 5vdc power and level shifting if it becomes a problem or the lawn stops needing mowing.

6

I think you can choose TFT LCD for another monitor. I’ve used it before. It’s really good

7

The interface is compliant to TTL which means it will work with 5V level as input.

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8

Is this the correct way to wire the voltage reducer resistors?

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The Intelligent series are 5V signal as well as 5V supply, so I think the resistors need to be on the Nextion Tx instead of Rx for those displays.

9

There is no voltage divider on TX needed for 5V. Why do you want one for 3.3V?

10

Teensy 3.6 and 4.1 are not 5V compatible, so Tx from Nextion needs to be 3.3V. Earlier versions of Teensy were 5V compatible.

11

The max. output from 2.4" Nextion displays is only 3.3V. If you don’t talk about 2.4" displays you should start a new topic as otherwise you will only confuse people.