65/67/97//41 Home-made mag cards

[Matt Agajanian]

Hi all.

Now that the magnetic card era is quite behind us, how can mag cards be made for each model?

[Kostas Kritsilas]

All of the models you named use the same card type. The HP-71 and the HP-75 (if it uses cards) are different, and much harder to make, as they have embedded timing marks/tracks due to their being pulled by hand.

[blackjetrock]

(09-18-2022 01:41 AM)Kostas Kritsilas Wrote:  All of the models you named use the same card type. The HP-71 and the HP-75 (if it uses cards) are different, and much harder to make, as they have embedded timing marks/tracks due to their being pulled by hand.

Has anyone made these cards? It looks like the timing tracks are recorded magnetically, is that correct?
Has anyone found a source for magnetically coated card, plastic or paper?

Andrew

[Matt Agajanian]

(09-18-2022 01:41 AM)Kostas Kritsilas Wrote:  All of the models you named use the same card type. The HP-71 and the HP-75 (if it uses cards) are different, and much harder to make, as they have embedded timing marks/tracks due to their being pulled by hand.

I see your point. I’m also curious about construction—the card stock, how to create a magnetic strip layer, its thickness, how slick the card should be for the mechanism to pull the card through, and so on.

[Sylvain Cote]

HP Journal, May 1974, HP-65 Calculator Issue.

Quote:Designing a Tiny Magnetic Card Reader
by Robert B. Taggart, pg 15-17

HP Journal, Nov 1976, HP-67/97 Calculator Issue.

Quote:A Pair of Program-Compatible Personal Programmable Calculators
by Peter 0. Dickinson and William E. Egbert, pg 2-8

HP Journal, March 1980, HP-41 Calculator Issue.

Quote:Card Reader Offers Compatibility and Expanded Capability
by David J. Lowe and Patrick V. Boyd, pg 12-15

HP Journal, June 1983, HP-75 Portable Computer Issue.

Quote:Handpulled Magnetic Card, Mass Storage System for a Portable Computer
by Kenneth R. Hoecker, James R. Schwartz, Francis A. Young, and Dean R. Johnson, Pg 15-23

The HP-75 Production Card Recorder
by David B. Patton, pg 20-21

Integration of the HP-75's Handpulled Card Reader Electronics in CMOS
by Thomas J. Arnold and Billy E. Thayer, pg 24-26

65 Notes & PPC Journal also contains several articles on the card reader subject.
These journals and others are available in the PPC Archive USB drive.