HackadayIt’s 1979 – What Exactly Did That ∫ Key Do?
It’s 1979 – What Exactly Did That ∫ Key Do? https://hackaday.com/2026/03/10/its-1979-what-exactly-did-that-%e2%88%ab-key-do/
#Classichacks #ReverseEngineering #Algorithm #HP #Hpcalculator #Reverseengineering #ScientificCalculator
#Classichacks #ReverseEngineering #Algorithm #HP #Hpcalculator #Reverseengineering #ScientificCalculator
Jack C.Found an HP 48GX #calculator in a drawer at work loaded with corroded batteries. Took it home and started cleaning it up, popped in fresh batteries and it's working 100%
The ON key is flakey but everything else works, and after browsing some forum posts the ON key works if you apply slight pressure where the zebra strip connects the keyboard to the PCB
I'm adopting it. It's mine now.
Stefan Wolfrum 
YAY! Successfully upgraded my > 10 years old HP-12C's firmware to the new 2025 version which now allows to dump and restore the calculator’s memory via cable to/from my Mac. 😊 #calculator #hpcalculator #hp12c #firmware #hewlettpackard – To see your HP-12C’s firmware version: When the calc is off hold g & ENTER and press ON. Then press 2 to see the checksum, press any key to see the date, again any key to see a copyright notice, again a key to return to the 1.L 2.C 3.H menu. Press ON to exit. 😉
Pssst … It's solving a #Sudoku! 😎 Here's the code, for the curious: https://hp-15c-simulator.de/programs/Sudoku%20Solver.htm #hp15c #hpcalculator #programmablecalculator #retrocomputing #moravia #hp #hewlettpackard #calculator #calculators #pocketcalculator
R.L. Dane 
🍵 
Now that's a lovely blast from the past!
Prof Lutz
SwissMicros DM15C and DM15L Review
ahimsaAny HP calculator fans out there?
A friend of mine runs a site called "The Museum of HP Calculators"
The Museum of HP Calculators
The Museum of HP Calculators displays and describes older Hewlett-Packard calculators. There are also sections on calculating machines and slide rules as well as sections for buying and selling HP calculators, an HP timeline, collecting information and a software library.
Anton (PD5ANT)
Digital Mark λ ☕️ 🕹 👽HP Computer Calculator for MATH AND SCIENCE!
https://archive.org/details/0808_Computer_Calculator_for_Math_and_Science_05_28_16_00
Really good little demo of doing physics on a plotting calculator. But the best part is at the end:
If you amortize it for 5 years, and divide by all the student workload, you get the remarkable cost of 5¢/program (40¢ in 2024 USD)! What a bargain!
By my calculations… that's $7,020 ($56,843 in 2024 USD).
Computer Calculator for Math and Science : Free Download, Borrow, and Streaming : Internet Archive
Great 1970s early computer footage. Hewlett-Packard computer model 9100 Computing Calculator. Physics class uses computing calculator and X-Y plotter in...