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New Multi Calculator
10-29-2017, 05:03 AM
Post: #21
RE: New Multi Calculator
(10-28-2017 08:22 PM)Francois Lanciault Wrote:  Hi, very interesting project.

Can I ask what is the speed relative to the original models ? Especially the programable ones ?

Thank you.

As close as I can get to the original.

cheers

Tony
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10-29-2017, 10:12 PM
Post: #22
RE: New Multi Calculator
In the NP-25 board, there is the possibility to switch between a slow mode, close to the HP 25 speed, and a fast mode, about 6 times faster.
Of course, I don't know if such a feature would be possible in your board (or even desirable).

Jean-Charles
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10-30-2017, 02:46 AM
Post: #23
RE: New Multi Calculator
(10-29-2017 10:12 PM)Helix Wrote:  In the NP-25 board, there is the possibility to switch between a slow mode, close to the HP 25 speed, and a fast mode, about 6 times faster.
Of course, I don't know if such a feature would be possible in your board (or even desirable).

I can certainly understand that almost any amount of enhancements can be made to these calculators, but I prefer to keep them running as close as possible to the way they were.

I have finished the first draft of the PCB. It measures approx. 120mm x 60mm.

cheers

Tony
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10-30-2017, 09:24 AM
Post: #24
RE: New Multi Calculator
Hi all,

Just finished the first design of the PCB.

I've ordered parts and will have to wait until they all get here before I can 100% verify the board.

I'll have to populate one board before I can test the HP19c because I need some of the hardware working.

The board can be powered by 3AAA cells, or directly from the USB port of a PC.

cheers

Tony


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11-01-2017, 07:36 PM
Post: #25
RE: New Multi Calculator
(10-30-2017 09:24 AM)teenix Wrote:  ...
The board can be powered by 3AAA cells, or directly from the USB port of a PC.
...

Has ever somebody tried to power a LED calculator with a cell phone battery like a BL-5B, combined with a possibility to be charged over USB? So it should be possible to build a quite small package. Or are the current to high for a cell phone battery.

Dani
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11-01-2017, 07:48 PM
Post: #26
RE: New Multi Calculator
(11-01-2017 07:36 PM)Dani R. Wrote:  
(10-30-2017 09:24 AM)teenix Wrote:  ...
The board can be powered by 3AAA cells, or directly from the USB port of a PC.
...

Has ever somebody tried to power a LED calculator with a cell phone battery like a BL-5B, combined with a possibility to be charged over USB? So it should be possible to build a quite small package. Or are the current to high for a cell phone battery.

Dani

It is possible, but then there is the added cost of specialty connectors, battery charging circuitry etc. You would also have to pick a type that is expected to be around for awhile too.

cheers

Tony
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11-01-2017, 08:13 PM
Post: #27
RE: New Multi Calculator
I'll have a portable headphone amplifier with a BL-5B battery. They decide for this type when Nokia does not exist anymore. But there are lot of sources, on eBay and Aliexpress etc. There must be still lot of device asking for a BL-5B. But yes, the charging circuit also need place and money.

Regards

Dani
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