3D printed battery cover for Hewlett-Packard 100LX/200LX

One of the most typical hardware failure of HP 100lx/200lx is a broken battery cover latch. That’s why a spare 3D printed battery cover would be a good option even if your current battery cover is intact. A free 3D model of the battery cover is available on Thingiverse. However, I was not satisfied with the quality of this model, therefore I’m glad to present you a custom (improved) version.

You can download this model for 3D printing here: HP 100LX battery cover.stl.

Testing the plotting function of HP 100lx

Plotting the function f(x)=1/sin(1/x) is a very difficult task. Few graph plotters are able to draw the function correctly.
Unfortunately, the built-in graph drawing program in the HP 100lx also does not quite cope with this task. Obviously, the specified function never takes values in the range (-1; 1).

Samsung Galaxy Z Fold 2 as the evolution of communicators

Samsung Galaxy Fold can be compared with devices like Sony Tablet P or Toshiba Libretto W100, because they fold into a tablet with two screens in the same plane.
But it is also quite appropriate to compare with communicators, whose external interface was used for phone calls, and the device itself was laid out to increase productivity. From this point of view, the Galaxy Fold is the result of more than 20 years of evolution of communicators.
The photos below reflect 24 years of the evolution of communicators, starting with Hewlett-Packard OmniGo700LX Communicator Plus (released in 1996) and ending with Samsung Galaxy Z Fold 2 (released in 2020).

Hewlett-Packard’s first handheld

Hewlett-Packard has played an exceptional role in the history of handheld computers. This company gave us truly remarkable palmtops 100LX/200LX, PDA iPaq hx4700 and Jornada 720. Some people still use these devices on a daily basis.
But what was the first handheld computer created by Hewlett-Packard?

You may consider HP-75C as the first HP handheld. The device is not very small, and the possibility of using it as a handheld is questionable.
But actually it depends on the criterias of a handheld computer.

Another candidate is the HP-67, which was introduced in 1976.
HP-67 was world’s first Turing-Complete handheld device. This is a strong argument in favor of transferring this device from calculators to the category of handheld computers.

Handhelds in Computer History Museum

Computer History Museum in Mountainview, CA is the largetst computer museum in the world. It contains very interesting exhibition of mobile computers, including handhelds.
Here is a small gallery of extraordinary items, like PalmPilot prototypes.

Lots of other remarkable photos from this museum, which are not related to handheld computers are presented in the Computer History Museum gallery.

You can take a virtual visit to CHM here: Computer History Museum, Mountain View, United States — Google Arts & Culture or CHM Revolution Tour – Mobile Computing: PalmPilot.