Back in the days before the widespread adoption of smartphones, Palm was the market leader in PDAs. If you had one of those you’ll probably remember taking notes by writing those funky “Graffiti” characters and tapping your stylus onto, usually, a green monochrome screen. Some models even came with a battery-hungry backlight, but for the ultimate display experience you had to buy the Palm IIIc that came with a backlit full-colour display.

While revolutionary for its time, it was hampered by the technology available: the CCFL backlight took a second to start up, and even with the screen at full brightness it was rather dim by today’s standards. [TobleMiner] fixed these issues by designing a module to retrofit an LED backlight into your Palm IIIc.

The new backlight consists of a long, thin PCB designed to fit exactly where the CCFL tube sits. The PCB holds twenty-one white LEDs along with their current-limiting resistors to provide even illumination from top to bottom. A little MOSFET soldered onto the mainboard ensures the new backlight also correctly responds to the device’s “brightness” setting. [TobleMiner] recommends to remove the bulky CCFL transformer from the Palm’s mainboard to disable the corresponding circuitry and save a bit of weight.

The end result is understandably hard to capture on camera, but apparently gives the screen more vibrant colours. In any case, this might be a useful hack for anyone with a Palm IIIc with a broken backlight, though we can’t remember if that was a common issue. If you’re among those who still use original Palm devices, you might like this Palm-compatible Bluetooth keyboard. Don’t have a classic PDA? You can also run PalmOS on modern custom hardware.

They have backlights? I think I missed that.

I’ve been pondering adding an LED or two to a portable CD player, since the small readout is hard to read withkut a flashlight.

Most Palm OS devices had screen illumination of some sort, save the first few models. The IIIc and Visor Prism were the only ones with a CCFL backlight, if I remember correctly. Later color devices moved to LEDs

I’ve used my M100 for a few years without knowing it had a backlight, until I upgraded to a new one and decided to attempt to hack a backlight into the device. Upon trying to remove the front panel, I accidentally pressed and held the power button and to my surprise the screen lit green!

in 2004 i had a samsung sph-i300 which is basically a palm iiic with a phone tacked on. i loved palmos as a user and as a developer. i was lukewarm on the color display, i don’t think it was an actual improvement on the b&w screen in the palm vx. but what i remember is that sometimes it would crash when you went to answer a phonecall. one day, i said “YOU WILL NEVER DO THAT AGAIN!!!” and i grabbed a nearby screwdriver and obliterated it.

i’m still mad at that phone. you can’t say “tft display on a palm” without raising my ire :)

Fun fact, the backlight or screen ran at a really annoying high frequency buzz. There is a hack to run it at a different hz, which works pretty well. Palm V I think. Palm should have fixed it.

That’s the low frequency AC for driving the Electroluminescent backlight. There is a sweet spot where the backlight performs optimally. Changing the frequency chances the brightness and the color a bit. The actual backlight part is acting like a large plate capacitor, vibrating to the driving waveform when excited.

This both saddens me and cheers me up simultaneously. I like the idea that retro/vintage gets so much love and attention, but I’m also sad that we haven’t gotten anything better than LEDs yet. It’s as if progress or creativity has comming to a halt. 🤷‍♂️

IMHO it feels like today’s youth or the average tinkerer below 25 doesn’t even know anything else anymore, right? Humble incandescent lamps have vinyl status by now, hm? What about OLEDs or electroluminescense with a white colour? 😃 Something with a warm white colour, maybe? Please? 🙂

This article made me pull out my Palm V and its Magellan “Streetfinder GPS” and install the batteries. (both still work and the GPS still devours batteries)

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