LEDs Give HP 3457A DDM’s LCD Display The Boot

Have you ever been so frustrated with a digital display that you wanted to rip the whole thing out and create a better one? That is exactly what [xi] did. Replacing their constantly used HP 3457A multimeter’s LCD display with a brighter LED one¬†was a necessary project — and a stress reducing one at that.

While this digital multimeter is well-known for its reliability, its standard display is rather lacking. In fact, there are several mods already out there that simply add a backlight. However, as [xi] notes, LCD screens always have a certain angle where they still don’t quite show properly. So this hack reverses the LCD’s protocol and details the process of creating new LED display.

The issue of dim displays that comes with traditional digital multimeters is not a new one. One solution to this that we have seen before is a hack where someone decided to add a backlight onto their cheap multimeter. [Ken Kaarvik] got around the dimness altogether by giving his multimeter a wireless remote display of his choosing. It is interesting to see the different solutions that are made to the same nuisance. The first item on the agenda of [xi]’s hack was to successfully analyze the HP LCD protocol. With the aid of an ATmega32, the digits were decoded throughout the transmission frames.

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40 MSPS Digital Oscilloscope

If you can fabricate single-sided circuit boards at home you can build this digital oscilloscope. It uses mostly through-hole components with just a couple of surface mount chips to contend with. An ATmega162 handles the hardware end of things with a CPLD used to manage the sampling rate. Data is displayed on a 240×128 LCD display which will be the most expensive component to acquire. It’s still a lot cheaper than buying a commercially available oscilloscope, even if you get a base model and hack it to unlock all the features.

[Thanks Juan]