My project is a new design for the homemade analog oscilloscope clock, similar to my previous design but able to drive different and larger CRT types, like the 3BP1 shown above. The segments which make up the characters are generated as a continuous line, arc or circle by using an analog switch and digital potentiometers and rheostats controlled by a microcontroller to manipulate an analog signal (sine wave) from an oscillator. This is quite different from my previous method of using vectors (dots) to draw the display point to point. The board has pots to adjust vertical & horizontal height / width, focus, astigmatism, brightness, and vertical and horizontal centering, as well as oscillator shape, oscillator gain and phase shift.
The new board starts with the same basic design as my previous models, but using a different type of supply for high voltage. The low voltage, wave shaper and blanking and deflection circuitry are similar but adjusted for higher voltage requirements, with some slight changes. The method of actually drawing the display begins with an oscillator configured to generate a sine wave which is switched by an analog switch to the deflectors, and positioned & sized by the digital pots. The microcontroller programmed with my firmware handles all this amazingly well !
The kit is similar to the original OSC4.7 kit, but adjusted to drive different CRT types. It comes with everything you need to build it yourself, except the crt and an enclosure. It should work well with most small relatively low voltage crts, as in my previous kit version. The kit will be a really challenging build, which will make it the more rewarding to the builder who is able to complete it and adjust the controls to optimize the display ! As always, I will be available for Q & A and ready to supply any docs I have for different crt types.
The deluxe version will be built using the pledger's choice of either the OSC5.4 driving a 3BP1 (or similar) CRT with choices of blue tint or clear enclosure and either blue or green solder masked PC board, or the OSC4.7 version driving choice of CRT from the 2BP1, 6Lo1i, DG7-6 or similar CRTs with the same options for enclosure & PC board colors.
Risks and challenges
Designing the circuitry to drive the analog portion of this clock was challenging ! I had a slight hitch re-designing the blanking circuit, which is critical, but worked it out. I wanted everything to be as simple as possible and to be driven by a single 5VDC supply. The risk of doing it this way would be not to sacrifice the quality and still keep the cost down. Overall, I am very happy with the design.Learn about accountability on Kickstarter
- (30 days)