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Pseudonymous maker “Sunshine701c,” hereafter merely “Sunshine,” has designed a Teensy-powered adapter which helps you to join the keyboard of a classic Hewlett-Packard 200LX palmtop to a contemporary PC as a USB system — as a part of a undertaking to upcycle a deceased instance of the system.
“I am engaged on a undertaking for the time being, mainly sticking a Raspberry Pi into the case of an previous [HP] 200LX palmtop laptop that broke on me,” Sunshine explains. “The beginning of this undertaking is to adapt the previous keyboard in order that it may be used as a regular USB keyboard. I used an previous Teensy 2.0 microcontroller and kbfirmware.com (very previous I do know) to [do] this, together with a customized interposer PCB to adapt the very bizarre pad spacing on the keyboard connector to the Teensy.”
A cautious tracing of a classic palmtop’s keyboard circuit delivers an adapter for a USB controller. (📷: Sunshine701c)
Launched in 1994, the HP 200LX was a palmtop PC constructed round an Intel 80186-compatible processor working at 7.91MHz and supporting as much as 4MB of RAM with storage enlargement out there by way of a PCMCIA slot along with the system. The bottom-performance present Raspberry Pi mannequin, in the meantime, is the unique Raspberry Pi Zero, which boasts a 1GHz CPU and 512MB of RAM.
Inserting a Raspberry Pi into an HP 200LX, then, could be one thing of an improve — although Sunshine was a request. “I urge, PLEASE DON’T tear aside a wonderfully working 200LX for a undertaking like this,” the maker writes. “I tore mine aside as a result of the LCD and [motherboard] had been each busted. Until you are in the identical boat, with a damaged keyboard AND LCD, think about using a distinct small type issue keyboard, it’s going to most likely be simpler to implement and use, I am solely utilizing this one to utilize previous know-how that may in any other case be thrown out.”
The maker has launched the board design and supply code for others to make use of in the event that they too have a deceased 200LX at hand. (📷: Sunshine701c)
To get the keyboard speaking to present methods, Sunshine needed to probe every hint on the versatile circuit to determine which key corresponded to which pin on the weird connector. With that map in thoughts, the maker constructed an interposer board which sits between the keyboard connector and a Teensy 2.0 microcontroller board — which, in flip, listens for key presses and sends them over USB to a contemporary host machine.
Extra data on the undertaking is offered on Sunshine’s Reddit submit, whereas supply code and KiCad undertaking recordsdata have been printed on GitHub underneath the reciprocal GNU Basic Public License 3.
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