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Another HP41C Simulator
05-07-2021, 12:33 AM
Post: #1
Another HP41C Simulator
I've been working on a HP41C simulator.

I wonder if there is any interested in this project.

It is built around the popular ATMEGA328 running at 8MHz on a 3V lithium coin cell. All off the shelf thru-hole parts.

The current state is:
Simulating a HP-41C with extra 128 registers. 192 registers in total.
128x64 lcd display.
Speaker.
Shows X, Y and Z stack registers.
3 run speeds: Normal, 50% faster or as fast as posible.
Has working clock with time and date. But does not have the Time Module.
There is no way to upload programs other than by hand.
Memory is preserved on power off.

I'm in the process of optimizing and bug hunt.


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05-07-2021, 02:56 AM
Post: #2
RE: Another HP41C Simulator
(05-07-2021 12:33 AM)agarza Wrote:  I've been working on a HP41C simulator.

I wonder if there is any interested in this project.

Uh... Yes. Please.

One for me, and one for my friend Massimo, connoisseur of all things HP-41. And one for Sylvain, and one for... well, I think you get my point.

Thanks for sharing your project, we look forward to see this come forth.

--Bob Prosperi
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05-07-2021, 05:26 AM
Post: #3
RE: Another HP41C Simulator
Yet Another Key Layout. :)

Greetings,
    Massimo

-+×÷ ↔ left is right and right is wrong
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05-07-2021, 07:15 AM
Post: #4
RE: Another HP41C Simulator
Looks splendid!

For a later revision, can I recommend you take a look at the keyboard design of the Minstrel2? Here, the array of tact switches is overlaid by a second PCB with suitable large round holes, which gives lots of space to include printed key legends. This top PCB can even use a different colour for better contrast.
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05-07-2021, 02:10 PM
Post: #5
RE: Another HP41C Simulator
(05-07-2021 07:15 AM)EdS2 Wrote:  Looks splendid!

For a later revision, can I recommend you take a look at the keyboard design of the Minstrel2? Here, the array of tact switches is overlaid by a second PCB with suitable large round holes, which gives lots of space to include printed key legends. This top PCB can even use a different colour for better contrast.


Thats a great idea. I was planning on 3D printing the case and keypad.
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05-07-2021, 06:52 PM
Post: #6
RE: Another HP41C Simulator
Is that the Nokia LCD?

10B, 10BII, 12C, 14B, 15C, 16C, 17B, 18C, 19BII, 20b, 22, 29C, 35, 38G, 39G, 41CV, 48G, 97
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05-07-2021, 07:03 PM
Post: #7
RE: Another HP41C Simulator
(05-07-2021 06:52 PM)Ren Wrote:  Is that the Nokia LCD?

No, it’s not the Nokia 5110 display. The Nokia display is too small and has a very low resolution (84x48).
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05-10-2021, 02:20 AM (This post was last modified: 05-10-2021 02:23 AM by Ren.)
Post: #8
RE: Another HP41C Simulator
(05-07-2021 07:03 PM)agarza Wrote:  
(05-07-2021 06:52 PM)Ren Wrote:  Is that the Nokia LCD?

No, it’s not the Nokia 5110 display. The Nokia display is too small and has a very low resolution (84x48).

Thanks, I was just going by the relative size of the display and the hand holding the calc.
It might be something I'd be interested in buying, but I'm a real cheapskate. B^)

P.S. what is the 6 pin header (right of the display) do? I2C?
Will it be the way to download programs in the future?

10B, 10BII, 12C, 14B, 15C, 16C, 17B, 18C, 19BII, 20b, 22, 29C, 35, 38G, 39G, 41CV, 48G, 97
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05-10-2021, 02:26 AM
Post: #9
RE: Another HP41C Simulator
(05-07-2021 02:56 AM)rprosperi Wrote:  Thanks for sharing your project, we look forward to see this come forth.

Forth? I thought the ATMEGA328 was programmed in "C"!
B^)

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05-10-2021, 02:46 AM
Post: #10
RE: Another HP41C Simulator
(05-10-2021 02:20 AM)Ren Wrote:  
(05-07-2021 07:03 PM)agarza Wrote:  No, it’s not the Nokia 5110 display. The Nokia display is too small and has a very low resolution (84x48).

Thanks, I was just going by the relative size of the display and the hand holding the calc.
It might be something I'd be interested in buying, but I'm a real cheapskate. B^)

P.S. what is the 6 pin header (right of the display) do? I2C?
Will it be the way to download programs in the future?

The 6 pins you see are the standard AVR ISP Header used to program the firmware on the atmega.

Hopefully you wouldn’t need to reprogram the firmware if I do a good job. ?
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05-10-2021, 06:23 AM (This post was last modified: 05-10-2021 06:27 AM by Ángel Martin.)
Post: #11
RE: Another HP41C Simulator
(05-07-2021 05:26 AM)Massimo Gnerucci Wrote:  Yet Another Key Layout. Smile

Yes but this one has the virtue to keeping ON/USER and PRGM/ALPHA together (adjacent at least), and also the physical layout maintains the logical arrangement of the original keyboard, so for instance R/S really is key 84, back arrow is key 44 (ENTER will use two domes), etc.

Neither of these two conditions happened on the DM-41X, unfortunately. it's a constant effort to switch back and forth between the DM-41X and the real one; Near miss or near hit? to me it's a flaw - a shame I couldn't convince the design team of the importance of those criteria.
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05-10-2021, 06:52 AM (This post was last modified: 05-10-2021 06:54 AM by Massimo Gnerucci.)
Post: #12
RE: Another HP41C Simulator
(05-10-2021 06:23 AM)Ángel Martin Wrote:  
(05-07-2021 05:26 AM)Massimo Gnerucci Wrote:  Yet Another Key Layout. Smile

Yes but this one has the virtue to keeping ON/USER and PRGM/ALPHA together (adjacent at least), and also the physical layout maintains the logical arrangement of the original keyboard, so for instance R/S really is key 84, back arrow is key 44 (ENTER will use two domes), etc.

Neither of these two conditions happened on the DM-41X, unfortunately. it's a constant effort to switch back and forth between the DM-41X and the real one; Near miss or near hit? to me it's a flaw - a shame I couldn't convince the design team of the importance of those criteria.

Oh well, while I understand you from a programming perspective, I still prefer R/S in the bottom right angle and back arrow on the border: so 45 and 85 is better UI-wise, to me at least.

Greetings,
    Massimo

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05-10-2021, 03:04 PM
Post: #13
RE: Another HP41C Simulator
(05-10-2021 06:23 AM)Ángel Martin Wrote:  
(05-07-2021 05:26 AM)Massimo Gnerucci Wrote:  Yet Another Key Layout. Smile

Yes but this one has the virtue to keeping ON/USER and PRGM/ALPHA together (adjacent at least), and also the physical layout maintains the logical arrangement of the original keyboard, so for instance R/S really is key 84, back arrow is key 44 (ENTER will use two domes), etc.

Neither of these two conditions happened on the DM-41X, unfortunately. it's a constant effort to switch back and forth between the DM-41X and the real one; Near miss or near hit? to me it's a flaw - a shame I couldn't convince the design team of the importance of those criteria.

The idea was to keep the keypad arrangement the same as the original. But if I placed the ON/USER and PRGM/ALPHA key on the top, like the original, the calculator would be too tall. So I decided to place them in at least in the same order.
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05-10-2021, 03:09 PM
Post: #14
RE: Another HP41C Simulator
(05-10-2021 06:52 AM)Massimo Gnerucci Wrote:  Oh well, while I understand you from a programming perspective, I still prefer R/S in the bottom right angle and back arrow on the border: so 45 and 85 is better UI-wise, to me at least.

Afraid I have to disagree with you this time, it's not programming but overall usability. Every time I switch between them I need to readjust my muscle memory, a real hassle.

But it's water under the bridge at this point so...
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05-10-2021, 03:10 PM
Post: #15
RE: Another HP41C Simulator
(05-10-2021 03:04 PM)agarza Wrote:  The idea was to keep the keypad arrangement the same as the original. But if I placed the ON/USER and PRGM/ALPHA key on the top, like the original, the calculator would be too tall. So I decided to place them in at least in the same order.

Makes total sense to me and it is in accordance with "good U/I design practices": when building on an existing design do not alter the basic layout!
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05-10-2021, 03:55 PM
Post: #16
RE: Another HP41C Simulator
(05-10-2021 03:09 PM)Ángel Martin Wrote:  
(05-10-2021 06:52 AM)Massimo Gnerucci Wrote:  Oh well, while I understand you from a programming perspective, I still prefer R/S in the bottom right angle and back arrow on the border: so 45 and 85 is better UI-wise, to me at least.
Afraid I have to disagree with you this time, it's not programming but overall usability. Every time I switch between them I need to readjust my muscle memory, a real hassle.
I wholeheartedly agree with Ángel here, IMHO it was a HUGE mistake to change the keyboard layout for the DM41X.
I am not as forgiving as Ángel, I did use the DM41X for a time, but the modified layout and the less effective button click made me go back to the 41CL without hesitation.
To be fair, the production version of the DM41X keyboard has a way better button click than the previous hardware versions (DM41X beta and DM42).
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05-10-2021, 04:30 PM
Post: #17
RE: Another HP41C Simulator
(05-10-2021 03:55 PM)Sylvain Cote Wrote:  
(05-10-2021 03:09 PM)Ángel Martin Wrote:  Afraid I have to disagree with you this time, it's not programming but overall usability. Every time I switch between them I need to readjust my muscle memory, a real hassle.
I wholeheartedly agree with Ángel here, IMHO it was a HUGE mistake to change the keyboard layout for the DM41X.
I am not as forgiving as Ángel, I did use the DM41X for a time, but the modified layout and the less effective button click made me go back to the 41CL without hesitation.
To be fair, the production version of the DM41X keyboard has a way better button click than the previous hardware versions (DM41X beta and DM42).
I have to say that I like the DM41X, the keyboard on my beta version is better than on my DM42 and even if not as good as a real HP 41, it's not a pain point for me.
Regarding the layout, well the DM41X is not a clone of an HP 41: different case, dimensions, weight balance, different screen and different key pad, so having a slightly different keyboard layout is not a big issue for me. As Massimo I find having R/S on the bottom right corner and back arrow on the border to be quite natural and having PRG above R/S and close to CST is logical. The ON key is the one that I struggle the most with: the top right corner location is not natural for me, I keep pressing the bottom left key, as I'm used to the DM42, Voyagers, Pioneers keyboards (any HP calculator after the 41 has the ON key on the bottom left corner).

(and btw the idea that on the WP 43S the ON key will be in another weird and unique location - bottom right - comforts me in my preference for the C43 keyboard layout, even more now that I've experienced the double Shift mechanism with the WP34S on DM42)
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05-10-2021, 07:39 PM
Post: #18
RE: Another HP41C Simulator
(05-10-2021 04:30 PM)Didier Lachieze Wrote:  The ON key is the one that I struggle the most with

Yes, I have to agree with you on this.

Greetings,
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05-10-2021, 07:42 PM
Post: #19
RE: Another HP41C Simulator
(05-10-2021 03:55 PM)Sylvain Cote Wrote:  To be fair, the production version of the DM41X keyboard has a way better button click than the previous hardware versions (DM41X beta and DM42).

Yes, it has, and I use my DM41X way more than the 41CL nowadays.

Greetings,
    Massimo

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05-10-2021, 07:51 PM
Post: #20
RE: Another HP41C Simulator
(05-10-2021 03:10 PM)Ángel Martin Wrote:  
(05-10-2021 03:04 PM)agarza Wrote:  The idea was to keep the keypad arrangement the same as the original. But if I placed the ON/USER and PRGM/ALPHA key on the top, like the original, the calculator would be too tall. So I decided to place them in at least in the same order.

Makes total sense to me and it is in accordance with "good U/I design practices": when building on an existing design do not alter the basic layout!

Since the hardware has one column more on the keyboard, unfortunately you had to change the layout anyhow.
And I prefer to find two among the most used keys where my muscle memory knows they are. :)

Greetings,
    Massimo

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