Scope Clock Board Kit

The SCTV Scope Clock Board from Cathode Corner is the heart of a unique, hand-made timepiece that brings the time to life on a vintage cathode-ray tube. The hours, minutes and seconds glow gently in green numbers formed with a precision circle generator. Driven by a tiny yet powerful Teensy computer, the clock can also display poetry and play games.

The Scope Clock Board may be installed into any cabinet that you can imagine. A set of four knobs (controls and knobs not included) allows adjustment of the display brightness, focus and centering. The function encoder provides quick selection of one of several clock faces, haiku, Pong or Tetris.

The clock faces are designed for simplicity and beauty. The digits are reminiscent of Nixie tubes. Each digit is formed of circles, arcs, ellipses and lines. The extensive use of curves avoids the jagged appearance of the typical vector display.

Tetris uses the position controls as rotation and position controls for the falling block. given the unique characteristics of a vector display, the 'bucket' that the blocks are piled into is drawn as one outline object. Each hole in the bucket is drawn separately.

Pong uses the position controls as the paddle controls for the left and right side players. English may be applied to the ball by hitting it near the edge of the paddle. Each game goes up to 11 points.

There are hundreds of haiku available, displayed in a random sequence. Each is credited to its poet. 

The clock is easy to set up and use. The User Manual provides all the necessary guidance.

The Scope Clock Board is offered only as a kit. You will need to provide the controls (two 500K to 1M pots and two 10K pots), CRT, socket and cabinet. A wiring harness with 12 inches of wire for each connection to the CRT and the controls is provided. This kit is intended for the experienced electronics builder.

A complete, illustrated step-by-step assembly manual is provided. The surface-mount parts are soldered to the PC board for you and the Molex terminals are crimped to the wires, but all other steps need to be done by you. Requires a good soldering iron, good solder, and an assortment of hand tools typically found on an electronics workbench.

If you enjoy programming in the Arduino environment, the Scope Clock is a wonderful platform. The firmware that runs the clock is available on the author's Github page. Your code contributions are warmly welcomed.

The Scope Clock uses a precision crystal clock circuit to keep time to within 3 minutes a year. If this isn't accurate enough for your needs, a USB GPS receiver (GlobalSat BU-353S4) may be plugged in to keep the time accurate to a fraction of a second. A standard CR2032 coin cell keeps the onboard clock running in case of power failure, so the time only needs to be set once for years of operation.

The CRT may be any 2 inch to 5 inch (5 to 13 cm) electrostatic deflection oscilloscope tube with a 6.3V filament and requiring 1000 to 1500V total acceleration voltage. P1 and P4 phosphors are the longest lasting. Antique tubes with unbalanced deflection such as 2AP1 and 3AP1 are not recommended. It is possible to modify the board to operate with a lower voltage tube such as a DG7-32 or 1EP1. A voltage multiplier may be added to provide post-deflection acceleration (PDA) anode voltage.

The clock is powered by a 12 Volt, 1.5 Amp DC wall adapter. An American, European or universal adapter is provided as needed.

The Scope Clock schematic diagram has two pages. Enjoy them.