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zeitfest
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Joined: 31/07/2019
Location: Australia
Posts: 553

Posted: 01:50am 25 May 2025

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Anyone used a pico with a cheap 16x2 display ?
The TFT displays seem to be getting pricier and pricier so, thinking of a cheap and simple board using a pico and 16x2 module. .

The module is supposed to run off 5v, but the pico is 3.3v.
I ran a 16x2 module on a pico OK, with the usb supplying the 5v but it has risks
and ties it to a usb power. It is said that some modules are ok just using 3.3v and a dropping diode to push the logic levels down a little - but it is not guaranteed.

So, as a trial I have used the pico 3.3v outlet to run the LCD 5v with a little converter . It seems to run OK. That also would allow a pico with battery management to run the lot off a lithium cell, probably a bit noisy though.

There is a risk of accidental 5v from the display pins, may need dropping resistors.

I think I can squeeze the 16x2 and small keypad onto a 4x4 pcb with the pico, battery etc behind it. Is it worth it though ?

palcal

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Joined: 12/10/2011
Location: Australia
Posts: 1974

Posted: 02:11am 25 May 2025

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You can get 3.3v 16x2 displays Here
Cheaper ones on other sites.
Edited 2025-05-25 12:12 by palcal

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

zeitfest
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Joined: 31/07/2019
Location: Australia
Posts: 553

Posted: 01:12am 26 May 2025

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Thanks :) Had a browse and ordered some blue/white ones.

Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9531

Posted: 02:00am 26 May 2025

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Yes, the blue/white ones are nice.

Four-line LCD's are also available and supported by MMBASIC.

Smoke makes things work. When the smoke gets out, it stops!

EDNEDN
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Joined: 18/02/2023
Location: United States
Posts: 131

Posted: 03:02am 26 May 2025

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Yes! The Blue background with White characters are the easiest to read.
I definitely recommend the 20x4 displays just because even the larger size still leaves you trying to squeeze in everything you want on the display. 16x2 is way too tight of fit (for me).

ebbandflow
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Joined: 31/08/2023
Location: United States
Posts: 36

Posted: 09:57pm 26 May 2025

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I have used a few of those HD44780 LCD's and the 5v variety are fine for Picomite with no risk. When you tie the R/W pin low, the data bus is never energized from the LCD (5v) side. The Busy pin is not used and not connected, therefore no worries running a 5v LCD from the VUSB pin of the Pico.
Edited 2025-05-27 08:01 by ebbandflow

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