Futuristic One-Hertz Competition: HP's Logic Probe Steps into Tomorrow
In the world of electronics, old doesn't always mean obsolete. This is beautifully demonstrated by the hacked HP 545A logic probe, a 45-year-old device that has been given a new lease of life thanks to a clever modification by electronics enthusiast, Robert Morrison.
Originally designed for basic logic state analysis, the HP 545A was not equipped to handle the fast, complex signals found in today's electronics. However, Morrison saw its potential and decided to breathe new life into the stout and still useful device.
The heart of the transformation is an FPGA (Sparkfun Alorium FPGA board), which effectively gives the old probe a 'brain transplant'. The FPGA is programmed to count pulses, measure pulse widths, and track timing of signals in modern high-speed circuitry, enabling the probe to handle the demands of today's electronics.
The FPGA also drives a small display on the probe, offering the user a clear, quantitative readout in real time. This upgrade turns the classic probe into a more intelligent, digital measurement tool suitable for debugging fast digital signals, a common requirement in modern electronics designs.
The hacked logic probe is not just a fast device; it also fits the criteria for the One Hertz Challenge, a competition that requires a device to perform an action once per second. Despite its high-speed capabilities, the probe resamples and updates the display once per second, ensuring it meets the challenge's requirements.
Morrison's creation has found a niche in today's smaller hardware due to its stout build and form factor. It also boasts a UART output, making it even more versatile.
The hacked logic probe is currently entered in the 2025 One Hertz Challenge, and Morrison is actively developing further logic analyzer features for the device. If you're creating your own neo-retro-logic probes, you're encouraged to notify the tipsline.
In essence, the key modifications include replacing the probe’s original logic with an FPGA, programming the FPGA to count pulses and measure pulse widths and timings, adding a display to visualize these measurements, and enabling the probe to handle and analyze high-speed digital signals. This transformation has transformed the former rudimentary logic probe into a powerful debugging aid for modern high-speed electronic circuits.
Old scopes, probes, and other gear can often be well-built and worth combining with modern upgrades to create useful devices today. The hacked HP 545A logic probe is a shining example of this philosophy.
The FPGA (Sparkfun Alorium FPGA board) integration offers a 'brain transplant' to the old HP 545A logic probe, transforming it from a rudimentary device into a powerful tool for analyzing high-speed digital signals in modern electronics. The upgraded probe, designed by Robert Morrison, also includes a small display and UART output, making it a versatile addition to smaller hardware, and even meets the One Hertz Challenge requirements by resampling and updating the display once per second.
