NP-41 Emulator (may be)

[Chris Chung]

(09-28-2015 01:01 AM)Helix Wrote:  

(09-22-2015 01:05 PM)Chris Chung Wrote:  I will keep you posted on the progress and I welcome your comments / questions / suggestions.

I don't know if my comment is useful, but on your PCB diagram the "shift 7" writing seems to be FF instead of SF.

Thanks for the catch, will correct for the next PCB design. I am thinking of separating the keypad and the display + MCU into two PCB units. This will save PCB fabrication cost and potentially keypad upgrades.

(09-27-2015 11:16 PM)Zweb Wrote:  

(09-27-2015 10:58 PM)matthiaspaul Wrote:  So, you and Waon are working on a Nonpareil port and calculator hardware based on a microcontroller of ST's STM32 family, whereas Chris is working on a hardware based on Texas Instruments' MSP430FR6989, both to emulate the HP-41C in the end?

Greetings,

Matthias

Yes, exactly.

We have a couple of LCDs in Waon's hand so that Zweb and Waon can work on an alternative version. I did some digging and I believe they have good success on another calculator project, ArithMax.

I think them China student team has the edge of being accessible to fast and inexpensive parts, manufacturing services.

I am sure my design will lack a lot on speed. But hopefully my choice of MCU will beat the STM32 design on lowest power RAM retention (at 0.0 nA :-). I understand that Zweb will be using STM32L series w/ LCD segment driver so that would also be a one chip design focus on power savings.

(09-27-2015 10:17 PM)Benoit Maag Wrote:  

(09-22-2015 11:00 AM)Waon Shinyoe Wrote:  Here is a comparison of the original 41C screen and the newly built one:

Beautiful ! - it even looks better than the original (more neutral colors and better contrast)
I would be interested in buying a few if available (say 5)

Currently we have 10 sample units (of which at least one has been tested faulty), the plan is to make sure it will work on our design (via prototyping) and we will order production units. I haven't test them except Waon did drove them w/ DC. I still cannot believe we are able to get them fabricated in such cost and time, so I have to multiplex them and make sure everything is good when I receive them.

The production units can only be ordered at batches of 300 pcs. I envisage that the prototyping will take 4-6 weeks. The cost on the production units is very affordable, say cost of a cup of coffee (not StarBuck, more like Timmy's). Still there are the upfront engineering cost, shipping from factory, absorption cost on extra units, etc, etc. If there are enough interest, may be Waon can setup something later as it could be less expensive to ship from China.

During our discussion w/ the manufacturer, Waon wants it to look more closely to the original, the manufacturer I guess has already some templates for 14 segments so we opt for what they suggested. I just need them to be at the best contrast and use their proven layout would be safer.