Scratch built RPN programmers calculator

[BobVA]

From Hackaday, Simon Boak's beautiful build of an RPN calculator, built to replace a failing TI Programmer.

Click through to Simon's blog to see the multi-level OLED stack display - reminds me of a 9100!

Bob

[EdS2]

Nice! This is the keyboard approach:

Quote:I used soft rubber dome buttons rather than the typical clicky tactile switches. The buttons you see on the front are made from 2 pieces of laser cut black acrylic then plastic-welded into an upside down “T” shape. The flat side pushes down on the button, and the base of the “T” comes up through the top of the panel to replicate the button style of the TI Programmer.

[Maximilian Hohmann]

Hello!

(09-14-2022 07:34 AM)EdS2 Wrote:  Nice! This is the keyboard approach...

This must be the first time that someone actually tries to faithfully recreate a Ti keyboard ;-) All that's still needed for 100% authenticity is software that produces some random key bouncing...

But kidding apart, this really is a very nice project! I also like the display very much, even if it is not a true OLED display. A real OLED display is composed of individual LEDs, one for each pixel. This one is an LCD screen with an organic diode for backlighting. Otherwise it would be a lot more expensive (the display of this calculator can be found at Aliexpress for 15$/Euros).

Regards
Max

[Thomas Klemm]

(09-14-2022 01:06 AM)BobVA Wrote:  Click through to Simon's blog to see the multi-level OLED stack display - reminds me of a 9100!

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(09-14-2022 08:04 AM)Maximilian Hohmann Wrote:  I also like the display very much, even if it is not a true OLED display. A real OLED display is composed of individual LEDs, one for each pixel. This one is an LCD screen with an organic diode for backlighting. Otherwise it would be a lot more expensive (the display of this calculator can be found at Aliexpress for 15$/Euros).

Link for the lazy:

Well, not to Aliexpress but to DIY MORE instead.

[Maximilian Hohmann]

Hello!

(09-14-2022 10:52 AM)Thomas Klemm Wrote:  Well, not to Aliexpress but to DIY MORE instead.

Just an observation:
Interestingly, Diymore, who are in China, also have a store on Aliexpress. The price tag is more or less the same, but for people like myself who live in the EU, it is much more convenient to order through their Aliexpress store. Because VAT and shipping are already included in the price and the parcel is delivered to me and not to a customs office!

I have in the past already bought some items from Diymore and had no issues at all with them.

Regards
Max

NB: And another thing for those who think about building this or a similar calculator. The Arduino Nano it uses is quite limited in memory size and the library required for the dot matrix display already uses a lot of that. An alternative could be the "Arduino Nano Every". It is a direct replacement to the Nano, same size and also 5V logic, but uses a different microcontroller (ATMega4809) with almost twice as much memory and a higher clock speed. It is more expensive and there are fewer (or none?) cheap chinese clones on the market.