cathode for HP91

[Thomas Radtke]

(07-31-2015 08:04 AM)PANAMATIK Wrote:  Although it would need much less work than the new ACT and the concept would be rather easy, the development of a microcontroller based cathode driver is too expensive concerning SMD manufacturing costs for small quantities.

Maybe an Arduino Nano or similar would do. I guess you'd need 14 IOs for the display and keyboard and some control lines (3?).