How to power an LCD 1062 (5V) - Page 1
Forum section: electronics / beginners

author: Ram80
author_rank: Contributor
timestamp: May 25, 2024, 11:59:06 pm
content: I'm using a STM8S103F3P6 and LCD 1062. The stm8 needs 3.3v and the 1062 5v. I'm also using an St link v2 to program the stm8.I still have to solder the stm8 header pins then I'm good to start connecting the circuit.So how would I power the LCD since it needs 5v , is there a coin battery that would power both the stm8 and 1062?

author: selcuk
author_rank: Frequent Contributor
timestamp: May 26, 2024, 09:08:46 am
content: Those types of LCD modules needs high power. Using a coin cell is not a good idea. When you use a 5V LCD with 3.3V MCU, you can use a logic level converter chip like 74LVC8T245 or similar. But you need both 3.3V and 5V supply. There may be 3.3V version of those LCDs on the market. If it is a battery operated device, you may consider using LCD glass panels instead of LCD modules.

author: tooki
author_rank: Super Contributor
timestamp: May 26, 2024, 10:56:53 am
content: Quote from: Ram80 on May 25, 2024, 11:59:06 pmI assume you mean a 1602 character LCD (1602 = 16 characters per line, 02 lines).You can get 3.3V 1602 LCDs. They are actually the same as a 5V one, but with an ICL7660 negative-voltage generator preinstalled on the back, because at 3.3V, there usually isn't enough setting range on the contrast pin.The power consumption of a character LCD is dominated by the backlight. For example, on a standard 5V 1602, I just tested now with an ESP32 (a 3.3V MCU), with the LCD's Vdd at 5V, it draws 1.1mA, while the backlight (at 3.3V) draws 5.4mA. (The backlight is powered completely separately from the LCD itself.)A typical lithium coin cell, like a CR2032, is 3V, which is just barely above the STM8S103F3P6's minimum supply voltage of 2.95V. This means a very short run time before you risk the MCU misbehaving. Can you choose a similar chip from the STM8L series, the ultra-low-power series? They operate from 1.8 or 1.65V minimum. (The maximum is 3.6V, so can't use 5V with them.)If you can't use an STM8L and a 3.3V LCD, you'll probably be better off powering it all from three AA or AAA batteries, giving you 4.5V new, 3V when nearly totally empty. And the run time is vastly longer than coin cells, at lower cost.Note that a 5V 1602 LCD has absolutely no problems whatsoever with 3.3V data signals. A level shifter is not necessary.

author: tooki
author_rank: Super Contributor
timestamp: May 26, 2024, 11:01:30 am
content: Quote from: selcuk on May 26, 2024, 09:08:46 amIt's around 1mA for the LCD itself, 5...20mA for the backlight if present.Quote from: selcuk on May 26, 2024, 09:08:46 amAbsolutely unnecessary, the 5V character LCDs are perfectly happy with 3.3V signals.Quote from: selcuk on May 26, 2024, 09:08:46 amIf you're running a 5V LCD and a 3.3V MCU, you need both supplies anyway.Quote from: selcuk on May 26, 2024, 09:08:46 amThere are, and 5V modules can be converted to 3.3V if needed, though it's easier to just buy them preconfigured correctly.Quote from: selcuk on May 26, 2024, 09:08:46 amDo you mean a bare LCD panel without a controller? If there's a controller, it makes no difference whether it's on a PCB (as a module) or a COG (chip on glass) display.

author: pcprogrammer
author_rank: Super Contributor
timestamp: May 26, 2024, 11:08:57 am
content: Quote from: tooki on May 26, 2024, 11:01:30 amAs long as you don't use the read functionality.

author: Ram80
author_rank: Contributor
timestamp: May 26, 2024, 11:26:46 am
content: Well I'm trying to build a small gadget. As I'm knew to electronics I'm learning all the time. It seems I need a segmented LCD display and an ultra low power MCU. It's difficult ATM trying to work out what components to use as there are so many. I'll use the stm8 and 1602 to prototype and learn from them I'll search out cheaper components.

author: tooki
author_rank: Super Contributor
timestamp: May 26, 2024, 12:16:19 pm
content: Well what exactly are you trying to build?Segment LCD? Like numeric only?

author: selcuk
author_rank: Frequent Contributor
timestamp: May 26, 2024, 12:28:31 pm
content: I meant bare LCD with pins and no controller. These are examples of LCDs for use with battery operated devices.https://www.orientdisplay.com/lcd-displays/glass-panels/When using back light, you should implement a mechanism to turn it off while not in use.You can use a display controller if MCU doesn't have an internal one. Such as PCF8553 or HT1621B.

author: coromonadalix
author_rank: Super Contributor
timestamp: May 26, 2024, 01:08:52 pm
content: but you can use small oled variants .... some are not power hungry ?

author: Ram80
author_rank: Contributor
timestamp: May 26, 2024, 03:14:26 pm
content: Yeh like these but even cheaper if that's possible, maybe you can order them from China?Also how easy are these to program can you find libraries online easy enough?

author: janoc
author_rank: Super Contributor
timestamp: May 26, 2024, 03:59:14 pm
content: Quote from: coromonadalix on May 26, 2024, 01:08:52 pmOLED is certainly at least the same if not more power hungry than a 1602. If you want really low power then bare reflective LCDs (with no backlight and assuming your MCU has the driver) or ePaper/eInk displays are the way to go.

author: selcuk
author_rank: Frequent Contributor
timestamp: May 26, 2024, 04:12:42 pm
content: If you are asking about glass LCDs, yes you can usually find them cheaper in China. Normally you create a design for your project and make them manufactured like ordering a PCB. Then it becomes a lot cheaper after paying the tooling costs (around $300 I believe).This is an example of a clock LCD. Supply is 3V and price is typical for a domestic dealer here. You can check shops in your country.https://www.ozdisan.com/tfts-lcds-and-led-displays/lcd-display-modules/character-and-numeric-lcd-displays/HS00B21-VAA/472237HT1621 has libraries online since many Arduino makers use them.

author: Ram80
author_rank: Contributor
timestamp: May 26, 2024, 05:38:35 pm
content: Quote from: selcuk on May 26, 2024, 04:12:42 pmThese look very nice, thanks. If these are digit only then you can't create a menu in them?For example say I wanted to create a timer that could run for 100s , 1000s or 10000s and the users could ideally chose which option, is there any way I could reasonably do this in a digit LCD like these.It's so long since I've used one of these LCDs(like in a wristwatch) I can't remember how they create a menu like system

author: xvr
author_rank: Frequent Contributor
timestamp: May 26, 2024, 06:31:24 pm
content: Use OLED display. Its power consumption depends on what it display. Seehttps://bitbanksoftware.blogspot.com/2019/06/how-much-current-do-oled-displays-use.htmlYou can optimize display contents to lower power consumption.

author: selcuk
author_rank: Frequent Contributor
timestamp: May 26, 2024, 08:56:48 pm
content: Those LCDs have predefined segments (shapes). They are fine for a electricity meter, handheld multimeter, thermostat etc. May be it is possible to design menus with segments which have fixed places but don't have to be digits. Check this one for example:https://www.aliexpress.com/item/32320442310.htmlBut if you need a graphical display having pixels, the circuit will be highly complex. In that case using a LCD module may be a better option. You will then spend time for power saving solutions. Or, e-inks are low power as suggested before.

author: Ram80
author_rank: Contributor
timestamp: May 26, 2024, 09:28:31 pm
content: Quote from: selcuk on May 26, 2024, 08:56:48 pmI've just discovered what I call ZEBRA strip LCD screens. I pulled a digital tire pressure gauge to bits to see the electronics and it has a rubber strip with metallic in it connected to the screen. What's your opinion on these type of screens?

author: xvr
author_rank: Frequent Contributor
timestamp: May 26, 2024, 09:30:18 pm
content: You need support for bare LCD segments from your MCU. Not all MCU have it.

author: BillyO
author_rank: Super Contributor
timestamp: May 26, 2024, 09:39:27 pm
content: You could use a small boost module to get the 5V from your 3.3V.

author: selcuk
author_rank: Frequent Contributor
timestamp: May 26, 2024, 10:06:02 pm
content: Quote from: Ram80 on May 26, 2024, 09:28:31 pmSame LCD glass panel. Manufacturer doesn't attach the through hole pins so you need to make contact with that pink foam conductor base.

author: mariush
author_rank: Super Contributor
timestamp: May 26, 2024, 10:16:45 pm
content: There's lcd displays that don't need backlight to workSeehttps://newhavendisplay.com/blog/transmissive-vs-reflective-vs-transflective-displays/tldrTypes of LCD modes:Transmissive LCDs require a backlight for clear visibility.Reflective LCDs do not have a backlight and rely on external light sources.Transflective LCDs combine both transmissive and reflective properties.Here's alphanumeric / character LCD displays :https://www.digikey.com/en/products/filter/lcd-oled-character-and-numeric/99Here's graphical LCD displays :https://www.digikey.com/en/products/filter/lcd-oled-graphic/107You can put filters there to see only displays that are REFLECTIVE or transflective , and then optionally choose only the ones that work natively with 3.3v or less.Here's an example of 8x2 that's reflective and runs on 3.3v :https://www.digikey.com/en/products/detail/newhaven-display-intl/NHD-0208BZ-RN-YBW-33V/2773588For graphical there's a bunch more displays available128x64 monochromehttps://www.digikey.com/en/products/detail/newhaven-display-intl/NHD-C12864GG-RN-GBW/1701323orhttps://www.digikey.com/en/products/detail/newhaven-display-intl/NHD-C12864B2Z-RN-FBW/1885690^ both run on 3.3v, same parallel 8 bit connection like the 16x2 displays, similar instructions (but instead of using the built in characters, you write pixels) , just have to add a bunch of ceramic capacitors because on the back of the lcd there's a charge pump to produce ~9v for the lcd and they don't put the capacitors on the back of the lcd.they consume under 0.75mASharp also has some nice monochrome lcds without backlight or optional backlight , also easy to control using microcontrollers :https://www.digikey.com/short/qztmf122

author: jzx
author_rank: Regular Contributor
timestamp: May 27, 2024, 05:45:34 pm
content: Quote from: xvr on May 26, 2024, 09:30:18 pmYou can use also an external driver, through spi or i2c as the HT1621.https://es.aliexpress.com/item/1005005310998910.html?src=google&aff_fcid=a1252e88968d415bae5422fccef8b3f7-1716831474213-00658-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=a1252e88968d415bae5422fccef8b3f7-1716831474213-00658-UneMJZVf&terminal_id=9714673d91234a558469e534328b6f56&afSmartRedirect=y&gatewayAdapt=glo2espAn oled is less visible in day light, and more indoor, thats depends on your intentions. Also many oleds have troubles with burning.To do menus, you have to be imaginative with a 7 segments display, see the 80´s watches, vcrs,