Re: Selecting compatible Raspberry Pi components
I was talking about the original official 7 inch display from Raspberry Pi:
https://www.raspberrypi.org/products/raspberry-pi-touch-display/
I have one, the resolution's not wonderful (800 x 480) but it just
works. I changed from Stretch to Buster (Raspbian) with a blank SD,
the display works without doing anything extra. The touchscreen is a
capacitive or resistive matrix on the screen feeding an A/D converter
and it works: where you touch the screen is the same as a mouse click
there. Not sure about HDMI ones. This uses the DSI connector on the
board, doesn't involve the GPIO or HDMI at all. They power it from 2
pins on the GPIO but you can change that, it just needs 5 volts. Or
use that connection as the 5 volt input to the Pi and display both and
bypass the silly microusb.
BTW to emulate a Blackberry a Raspberry Pi ZeroW might be adequate.
It's single core so slower but much lower power. They have been run
on a single lithium cell but they complain about low voltage I think.
https://www.raspberrypi.org/products/raspberry-pi-zero-w/ There's no
DSI connector though.
On 5/4/20, Richard Owlett <rowlett@cloud85.net> wrote:
> On 05/03/2020 02:23 PM, Jeffrey Walton wrote:
>> On Sun, May 3, 2020 at 12:59 PM Richard Owlett <rowlett@cloud85.net>
>> wrote:
>>>
>>> I've been thinking about what a handheld computer COULD be.
>>> My image is heavily influenced by my recollection of Palm Pilot.
>>>
>>> My project goals are two-fold
>>> 1. create a personal data logger reminiscent of a Palm Pilot
>>> 2. become familiar with Raspberry Pi while using Debian as the OS
>>>
>>> My needs include:
>>> >2 hours battery life
>>> 4" by 7" nominal form factor
>>> touch screen input using a stylus
>>> display will be entirely character mode (40 chars/line would be OK)
>>> OS GUI not required except to say where stylus is
>>> OS shall be Debian {possibly with non-free drivers}
>>>
>>> I've not found found user friendly selection guides.
>>> A typical problem was not being able to know if a selection of
>>> components had mutually compatible I/O (electrical and physical).
>>
>> I can't speak for others, but I once I select the RPI (usually a RPI3
>> or RPI4), head over to Amazon and look for the accessories. Cases are
>> $10 to $30 USD, screens are $20 to $50 USD, etc. I've never shopped
>> for a battery so I can't really say anything about them.
>>
>> The only tricky thing I have encountered is screens. If you want to
>> keep the GPIO pins available for other work, like signals for buttons,
>> then you need SPI data connection for the LCD screen. The problem is,
>> SPI connectors are only available for 7" screens or above, which are
>> usually larger than I need.
>
> The page [1] for Adafruit's 3.5" display seems to say it can use either
> the GPIO connector or SPI. Determining which display worked with which
> Pi was a sticking point when I pursued this last year.
> [1] https://www.adafruit.com/product/2441
>>
>> You might also have some trouble with a case. Most cases have openings
>> for ports but not much more. If you are having trouble finding a case,
>> then buy one of those inexpensive 3D printers and make your own.
>>
>> Jeff
>>
>>
>
>
>
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