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With its default software, the H2 can function as an ebook or
as a slideshow viewer. The mode is selected from a boot up
title screen, which the user can return to from inside either
mode. Both modes show the same image set from the MMC card;
with only the way image transitions are initiated differing
between modes. The image set can be changed by removing the
MMC card and altering its contents, or by transferring content
to and from the card using one of the communications
interfaces. The operation of the book can be changed by
editing the shell scripts which control its behaviour, or by
writing and installing entirely different software.
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With the alkaline model, the battery tube cap is screwed in until
the Tx LED visible through the back or side of the case begins
to flash. With the Li model, the battery cutout switch is slid
to the on position.
Boot up takes about 10 seconds at this point, which
can hopefully be improved later.
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After power up, the display should flash and the menu screen
should appear. Select either slide show or ebook mode using
the up/down main buttons. The same image set is used for both
modes, but the transition between images will differ depending
on the mode.
Title Screen
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Push the down button to move forward and the up button to move
back. If you are at the beginning of the image set and you
press the back button, the same image will appear. If you are
at the end of the image set and press the forward button, the
same image will appear. Otherwise, pressing one of these
buttons will show either the previous or next image in the
set, according to the button. Press the small button with the
light gray center to return to the menu screen. Button input
is ignored until the image update is complete, which takes
1-2 seconds.
There is also a delay between button depression and when the
display starts to change when moving forward and back in the
image set. This is due to the time it takes the computer to
copy the image from the MMC card to RAM and decompress it, and
can vary from essentially zero to a few seconds, depending on
the complexity of the image (and thus its compressed size).
The file ebook.sh on the MMC card is used by the processor to
control operation in ebook mode. This file can be edited or
replaced to change behavior in ebook mode.
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In slideshow mode, all the images in the set are shown
sequentially in an infinite loop. The delay between images is
about 10 seconds by default.
Holding down the small button with the light gray center
through an image update will return you to the main menu
screen.
The file slides.sh on the MMC card is used by the processor to
control operation in slideshow mode. This file can be edited
or replaced to change behavior in slideshow mode, for example
to change the delay between image updates.
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Installing new batteries (alkaline model):
Use 3 AAA batteries. Always make sure to insert all three
batteries into the tube with the positive bump going in
first. Batteries should last around 3 hours in slideshow mode
with 10 seconds between image changes. Smaller delays between
images, in either mode, will reduce battery life. Longer
delays will increase battery life. Use very high quality
alkaline batteries, for example Panasonic Industrial batteries
(Digikey part number P146-ND).
Charging batteries (Li-model):
Plug the 12V power adapter into the H2 (and into a wall
socket). Batteries should charge in about 3 hours.
Battery life is currently shorter than it should be because
good power management software has not been written. Kernel
and bootloader modifications are required for putting the
Xscale into ultra low power mode between updates. These
projects have not been a top priority to date. So when the
book is just sitting there, the screen is not using any power
at all, but the Xscale is chewing up 100-200 mA.
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Adding new images to the image set
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The system uses the images stored on the mmc card in the
directory called images_bz. The images are PPM raw 8 bit
grayscale, 800x600 (landscape), compressed using the bzip2
algorithm. The order the images are shown is determined by
their order in a listing of the images_bz directory, so for
instance a.ppm.bz2 would be shown before b.ppm.bz2. Images can
be removed from the set by deleting them from this directory,
or moving them to another directory. Images can be added to
the set by copying them into this directory.
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Design partially original and partially ripped off from other websites
by Holly Gates
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