Limited edition calibrated Red Pitaya kit

Red Pitaya is a powerful instrumentation and prototyping module used by numerous electronics professionals and hobbyists as a general-purpose oscilloscope, signal generator or signal analyzer. It is also suitable for user-developed applications. Red Pitaya is now offering a calibrated version of this versatile module as a limited edition, eliminating the need for calibration by the user.

Although we would not denigrate the many photographic development and printing services (wh ich vary fram poar to fairly good), it is a fact that many serious amateur photographers would not dream of sending their carefully taken and exposed films to one of these bureaux. Many others are hesitant to do so. This article is aimed at all these photographers. It describes a darkroom timer that is calibrated in f numbers. This kind of calibration makes the timer much easier to use than the traditional ones that have a linear scale.

Temperature may be measured electronically with cornmercially available temperature- to-voltage converters. Since good-quality, calibrated ones are normally not cheap, the linear temperature gauge described uses an inexpenstve silicon transistor as sensor.

The Acorn Archimdes, well-known far its speed and good graphics facilities, has a video interface that allows programmers to design a variety of screen modes with the aid ofa programmablecontroller. As so often, this versatility has a draw-back: since the controller uses a fixed clock of 24 MHz, the frame frequency decreases the more pixels areused in the screen image. As a result, high-resolution screen modes have a tendency to cause flicker.Fortunately this drawback may be eliminated or nearly so by increasing the dock to 36 MHz: this has already been incorporated in the new A540 computers.