Here’s a Geiger Counter that makes itself at home inside of an old Ohmmeter (translated). [Anilandro] set out to built this radiation detector in order to learn how they work. Like other diy Geiger Counter builds we’ve seen, this project assembles a circuit to interface with a gas-filled tube which serves as the detector. [Anilandro] takes a few paragraphs to discuss how this works; the Geiger tube is basically a capacitor whose electrical characteristics change as an ionizing particle passes through it.
Once he had the theory worked out he scavenged some parts to use. A broken emergency light donated its transformer to provide the high voltage needed. The rest of the circuit was built on some protoboard, and a speaker was added to output the clicking noises that have become a familiar part of the detector hardware. The tube itself is housed in a wand that attaches to the base unit through a cable. Check out some test footage of the finished unit after the break.
Continue reading “Geiger counter built in an Ohmmeter enclosure”
[Segelfam] built his own scanning electron microscope. He based the machine around an old Vidicon tube, a video recording technology that was used in NASA’s unmanned space probes prior the Galileo probe in the late 1970’s. We struggle a bit with the machine translation of [Segelfam’s] original build log, but it seems that he filled the tube with helium in order to convert it for use as a microscope. But don’t worry, if you’re interested in this hack the information is all there – between the forum thread and build log – it’s just a matter of putting it all together to fill in the details.
In case you were wondering, the image to the upper right has been colored using Photoshop; the rest are straight from the SEM.
We know way too little about this subject but hopefully [Bob4analog] helped us learn a little bit more this time around. He’s building his own linear amplifiers on what looks like sheets of MDF. This is an evolving design and the two videos after the break show two different iterations. He’s salvaged several components, like transformers from microwaves, as well as built his own components like the plate choke to the right of the tubes in the image above. In standby, the amp sits at 2800 volts, warming the filament before the unit is switched on.
So what’s he got planned for this? Good question, but it appears that there’s more than enough power to drive a long-range transmitter.
Continue reading “Building linear amplifier prototypes”
[Brian Grabski] was asked by a friend to design and build a dolly that would move a camera during a time-lapse sequence. Above you can see the product of his toils, and the videos after the break show off the parts that went into the design and showcase effectiveness of the build.
The dolly is designed to ride on a pair of tubular rails. These can be bent to match any desired path and the dolly will have no problem following it thanks to two features. First, the triad of skateboard wheels on each of the three corners are mounted on a swivel bearing that allows them to rotate without binding. The other piece of the puzzle is a set of drawer slides that let the third support move perpendicular to the other two sets of rollers. A motor drives a geared wheel to move the dolly along the track with speed adjustments courtesy of the motor controller. There’s also a failsafe that will shut the system down when it runs out of track, protecting that fancy piece of hardware taking the pictures.
We’ve seen timelapse equipment that moves the camera in the past, but those hacks usually involve rotating the camera along and axis. This track-based setup is a well executed tool useful at all levels of photography. We can’t wait to see the arch-based dolly that is teased at the end of the demo video.
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The Warm Tube Clock is the new kid on the block of Nixie Tube clocks. It takes inspiration from, and uses the same voltage driver circuit as the Ice Tube Clock. But this one uses four tubes instead of that hard-to-find single tube. It has a few other tricks up its sleeve. The shield that hosts the tubes has been designed for two different types. It also hosts an RGB LED for each tube, which adds the green glow seen above, and has a couple of small neon indicator bulbs which serve as the colon between hours and minutes.
The driver board centers around an ATmega328 running about three thousand lines of code. The firmware offers a lot of options including sound feedback, and a setting for every clock, calendar, alarm, and LED color toggle imaginable. See for yourself as the settings video, embedded after the break, walks you through each stage of the menu. We can’t help but think you need an instruction manual to set this thing up.
Continue reading “Warm Tube Clock”
[M3talhead] takes us through a very informative repair of an old tube radio. In this case, his radio was from the late 30s. He was able to find the original data from Radiomuseum.org. He painstakingly dismantles the radio components and the cabinet. Instead of completely modernizing the internals, he replaces the bad parts and brings it back to functionality. He wanted to do an MP3 upgrade, but rather than wire directly into the radio, he built an AM transmitter for his mp3 player.
Check out this home made panaplex display. Panaplex displays are closely related to nixie tubes, but instead of layering individual numbers and lighting them separately, it uses pieces to build the numbers like a digital display. [Lindsay] managed to make one at home, using a jam jar as the vacuum tube. Argon as the gas in the tube gives it a pleasant purple color. We really think the end result is fantastic, you can see some build pictures and a run through of the numbers on the site. Unfortunately there aren’t any videos of the display in action.