5 ms·

The publication date is unclear, but the latest citation is 2011. It doesn't make economic sense anymore to use seven segment displays in new products, small TF

The publication date is unclear, but the latest citation is 2011. It doesn't make economic sense anymore to use seven segment displays in new products, small TFT/LCD and even OLEDs are cheaper. It probably does make sense to use them with legacy equipment that require a large certification effort (most of the examples are medical). The advice the author gives for situations where seven segment displays are used is good, though. What really doesn't make sense is using a seven segment font on a high resolution device to make the product seem more technological, I guess, but I don't think that was mentioned.

gray_-_wolf 2y ago
> It doesn't make economic sense anymore to use seven segment displays in new products, small TFT/LCD and even OLEDs are cheaper. Maybe cheaper, but what about power consumption? I would have expected them to need significantly more, which might matter for battery-powered devices.
- mytailorisrich 2y ago
  I suspect that simple LCD displays have the lowest power consumption (see wristwatches, etc).
  - xxs 2y ago
    They are not even remotely comparable when it comes to readability/contrast.
- hoherd 2y ago
  For that we have Memory LCD https://www.adafruit.com/product/3502 https://www.adafruit.com/product/3502
  - jonny_eh 2y ago
    How do those compare on price though?
    - moffkalast 2y ago
      Well that one's from Adafruit, so probably 10x the price of what's commonly sold.
  - nebula8804 2y ago
    While this display is really slick, it seems like it is still not available under multiple suppliers? If thats the case. that means its going to be more pricey than other options. I cant seem to find many cheap options on alibaba/aliexpress.
    - ClassyJacket 2y ago
      Apparently Sharp introduced the technology in 2009, so perhaps there's a patent expiring soon?
- outworlder 2y ago
  > Maybe cheaper, but what about power consumption? I would have expected them to need significantly more, which might matter for battery-powered devices. Seven segment displays are quite power hungry relative to what information they can display. LCDs sip power, the issue is their backlight.
  - bobmcnamara 2y ago
    Seven segment is a pixel layout. LCD/LED are pixel types. Seven segment LCDs are super low power, and can be made to reflect through ambient lighting.
    - olyjohn 2y ago
      Like how my calculator runs off of the the tiny solar panel that is built in and is powered by ambient light in the room.
      - gedy 2y ago
        I think some folks might be thinking of the older light-emitting 7 segment displays which used more power.
        bobmcnamara 2y ago
        Ah my bad, I was thinking of the early zero power seven segment numeric tape printers. The numitrons used a ton of power. Or was that VFDs?
- demondemidi 2y ago
  Unlit liquid crystal 7-segement displays are the lowest-power & lowest-cost solution. You're absolutely right. The person you're replying to clearly doesn't have experience in the low-power/low-cost embedded world. In that space even 1KB of SRAM is a liability.
eschneider 2y ago
Ah, but 7-segment displays are far easier to drive from a microcontroller, so even if an LCD is cheaper, it might make for a more expensive system.
- numpad0 2y ago
  Depends. I2C only takes two I/O pins.
  - samtho 2y ago
    That’s only part of the equation. Grid displays require a lot more memory and often power to drive. By contrast, a seven segment display requires 7 (or 8) LEDs and 8 bits per digit on the output stage, 4 bit in BCD, which can be fed via a shift register.
    - dfox 2y ago
      Almost any other display that you will reasonably use in a application that makes sense for segmented multiplexed LEDs will integrate internal controller, so instead of having to refresh the thing somehow you have a thing that is simply an peripheral hanging of some or other bus that just does its thing. And well, such things tend to be cheaper than seven segment LEDs (there is a reason why random almost disposable crap has graphical monochrome OLED panels)
  - petsfed 2y ago
    Granted, but as a sibling states, the other factor is firmware complexity. I can theoretically drive a high-resolution display on an 8-bit micro (although it may require with some clever bit banging to get I2C to work at all) but its trivial with a 7-segment display. And as a bonus, you don't have to involve anymore UI/UX design than to answer the question "what number should go here?"
    - numpad0 2y ago
      It'll be microcontroller equivalent of running full GNU/Linux to control an Internet of e-waste tea kettle, but CH32V003 + SSD1306 OLED + passives takes less than 10 parts total, no crystals needed, has plenty sample codes online, and costs ~$2 combined. Depending on the price of the final product, it could make financial or product design sense.
delfinom 2y ago
I can produce 3 inch or smaller segment displays for 30 cents a pop with up to 50 segments. At a MOQ of just 10k You can't touch that with TFT/LCDs. Not to mention the current consumption of a segment LCD display is measured in microamps. And the micros that drive segment LCD displays can easily be sub dollar.
- sandworm101 2y ago
  Durability and failure modes are also better with segment displays, which is why you still see them in military or aviation applications.
Suppafly 2y ago
>small TFT/LCD and even OLEDs are cheaper. How can that be true?
- rvbissell 2y ago
  My guess is: economies of scale, in 2024 (vs say, 1990)
  - Suppafly 2y ago
    I had considered that maybe new 7-segment displays aren't being made, so maybe they cost more for that reason, but even that doesn't seem like it'd be true.
- pclmulqdq 2y ago
  If you look at distributor single-unit quantities, they are close in cost. If you look at hobbyist stores, they are the same price (or more expensive for the seven-segment version). If you ask a factory in China to make you 1 million displays, the seven-segment version will be a lot cheaper. That's why new products use them. Even at 1k quantity from distributors, seven-segment displays are substantially cheaper.
- numpad0 2y ago
  Some Chinese display manufacturers are dumping lots of small, easy to use, postage stamp sized monochrome blue-white OLED at ~$1.5 apiece from 1 unit with free shipping, which had made it a viable replacement for 7-segments, couple power LEDs, even decorative logo displays, for small scale productions. It's not the case at all for real mass produced products, but not everyone is delivering thousands of units per month to Walmart. I personally don't necessarily support "just go graphical" sentiment, but such local minima do exist.
nebula8804 2y ago
Seems like many suppliers are coalescing on certain sizes/designs of OLEDs at the low end. All I see are these tiny blue/white displays or 1 inch full color. They all look the same and are boring at this point. I was hoping that we would get an explosion of different OLED display sizes and designs.
xxs 2y ago
LCD is much harder to reader, and a lot more complex to drive. Vibration wise I'd take potted 7-segment display as well. Single color is a benefit. OLED would have much shorter life, along with burn in - 7 segment ones tend to display very static info in many cases.

gray_-_wolf 2y ago

> It doesn't make economic sense anymore to use seven segment displays in new products, small TFT/LCD and even OLEDs are cheaper. Maybe cheaper, but what about power consumption? I would have expected them to need significantly more, which might matter for battery-powered devices.

mytailorisrich 2y ago
I suspect that simple LCD displays have the lowest power consumption (see wristwatches, etc).
- xxs 2y ago
  They are not even remotely comparable when it comes to readability/contrast.
hoherd 2y ago
For that we have Memory LCD https://www.adafruit.com/product/3502 https://www.adafruit.com/product/3502
- jonny_eh 2y ago
  How do those compare on price though?
  - moffkalast 2y ago
    Well that one's from Adafruit, so probably 10x the price of what's commonly sold.
- nebula8804 2y ago
  While this display is really slick, it seems like it is still not available under multiple suppliers? If thats the case. that means its going to be more pricey than other options. I cant seem to find many cheap options on alibaba/aliexpress.
  - ClassyJacket 2y ago
    Apparently Sharp introduced the technology in 2009, so perhaps there's a patent expiring soon?
outworlder 2y ago
> Maybe cheaper, but what about power consumption? I would have expected them to need significantly more, which might matter for battery-powered devices. Seven segment displays are quite power hungry relative to what information they can display. LCDs sip power, the issue is their backlight.
- bobmcnamara 2y ago
  Seven segment is a pixel layout. LCD/LED are pixel types. Seven segment LCDs are super low power, and can be made to reflect through ambient lighting.
  - olyjohn 2y ago
    Like how my calculator runs off of the the tiny solar panel that is built in and is powered by ambient light in the room.
    - gedy 2y ago
      I think some folks might be thinking of the older light-emitting 7 segment displays which used more power.
      - bobmcnamara 2y ago
        Ah my bad, I was thinking of the early zero power seven segment numeric tape printers. The numitrons used a ton of power. Or was that VFDs?
demondemidi 2y ago
Unlit liquid crystal 7-segement displays are the lowest-power & lowest-cost solution. You're absolutely right. The person you're replying to clearly doesn't have experience in the low-power/low-cost embedded world. In that space even 1KB of SRAM is a liability.

eschneider 2y ago

Ah, but 7-segment displays are far easier to drive from a microcontroller, so even if an LCD is cheaper, it might make for a more expensive system.

numpad0 2y ago
Depends. I2C only takes two I/O pins.
- samtho 2y ago
  That’s only part of the equation. Grid displays require a lot more memory and often power to drive. By contrast, a seven segment display requires 7 (or 8) LEDs and 8 bits per digit on the output stage, 4 bit in BCD, which can be fed via a shift register.
  - dfox 2y ago
    Almost any other display that you will reasonably use in a application that makes sense for segmented multiplexed LEDs will integrate internal controller, so instead of having to refresh the thing somehow you have a thing that is simply an peripheral hanging of some or other bus that just does its thing. And well, such things tend to be cheaper than seven segment LEDs (there is a reason why random almost disposable crap has graphical monochrome OLED panels)
- petsfed 2y ago
  Granted, but as a sibling states, the other factor is firmware complexity. I can theoretically drive a high-resolution display on an 8-bit micro (although it may require with some clever bit banging to get I2C to work at all) but its trivial with a 7-segment display. And as a bonus, you don't have to involve anymore UI/UX design than to answer the question "what number should go here?"
  - numpad0 2y ago
    It'll be microcontroller equivalent of running full GNU/Linux to control an Internet of e-waste tea kettle, but CH32V003 + SSD1306 OLED + passives takes less than 10 parts total, no crystals needed, has plenty sample codes online, and costs ~$2 combined. Depending on the price of the final product, it could make financial or product design sense.

delfinom 2y ago

I can produce 3 inch or smaller segment displays for 30 cents a pop with up to 50 segments. At a MOQ of just 10k You can't touch that with TFT/LCDs. Not to mention the current consumption of a segment LCD display is measured in microamps. And the micros that drive segment LCD displays can easily be sub dollar.

sandworm101 2y ago
Durability and failure modes are also better with segment displays, which is why you still see them in military or aviation applications.

Suppafly 2y ago

>small TFT/LCD and even OLEDs are cheaper. How can that be true?

rvbissell 2y ago
My guess is: economies of scale, in 2024 (vs say, 1990)
- Suppafly 2y ago
  I had considered that maybe new 7-segment displays aren't being made, so maybe they cost more for that reason, but even that doesn't seem like it'd be true.
pclmulqdq 2y ago
If you look at distributor single-unit quantities, they are close in cost. If you look at hobbyist stores, they are the same price (or more expensive for the seven-segment version). If you ask a factory in China to make you 1 million displays, the seven-segment version will be a lot cheaper. That's why new products use them. Even at 1k quantity from distributors, seven-segment displays are substantially cheaper.
numpad0 2y ago
Some Chinese display manufacturers are dumping lots of small, easy to use, postage stamp sized monochrome blue-white OLED at ~$1.5 apiece from 1 unit with free shipping, which had made it a viable replacement for 7-segments, couple power LEDs, even decorative logo displays, for small scale productions. It's not the case at all for real mass produced products, but not everyone is delivering thousands of units per month to Walmart. I personally don't necessarily support "just go graphical" sentiment, but such local minima do exist.

nebula8804 2y ago

Seems like many suppliers are coalescing on certain sizes/designs of OLEDs at the low end. All I see are these tiny blue/white displays or 1 inch full color. They all look the same and are boring at this point. I was hoping that we would get an explosion of different OLED display sizes and designs.

xxs 2y ago

LCD is much harder to reader, and a lot more complex to drive. Vibration wise I'd take potted 7-segment display as well. Single color is a benefit. OLED would have much shorter life, along with burn in - 7 segment ones tend to display very static info in many cases.