Make Your Own Fume-extracting Glove Box

diy-clean-box

Here’s an easy to follow guide for building your own glove box. It’s a lab tool that contains the project you’re working on to keep things in or out. For instance, we could have used this a few years back when we tried to add an acrylic window to a hard drive. Instead, we ended up putting several hours of work into a cool-looking paperweight. But it will also come in handy for chemistry experiments that generate harmful or dangerous byproducts.

The picture above tells most of the story, but [Jason Poel Smith] does include several good tips about the construction in his video. He uses weather stripping along the edges of the clear container to ensure a seal. The hose is used to provide negative pressure so that no fumes leak out. We figure adding a smaller hole on the opposite side with a charcoal filter will help air pass into the chamber to serve as a fume extractor.

We’ve already seen a similar setup for a reflow oven. Perhaps this is the perfect solution to protect yourself from 3D printing fumes. We’re sure you saw the headlines about 3D printing being as bad as smoking cigarettes.

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Geometry Class Just Got Augmented

ruler

Just about every engineer needs to take a drawing class, but until now we surprisingly haven’t seen electronics thrown into rulers, t-squares, and lead holders. [Anirudh] decided to change that with Glassified. It’s a transparent display embedded in a ruler that is able to capture hand drawn lines. These physical lines can be interacted with or measured, turning a ruler into a bridge between a paper drawing and a digital environment.

For the display, [Anirudh] mounted a transparent TOLED display with a digitizer input into a ruler. The digitizer captures the pen strokes underneath the ruler, and is able to interact with the physical lines, either to calculate the length and angle of lines, or just to bounce a digital ball inside a hand-drawn polygon.

There’s no word on how this display is being driven, or what kind of code is running on it. [Anirudh] said he will have some schematics and code available up on his website soon (it’s a 404 right now).

A Keygen For The Rigol 2000-series Scopes

A few weeks ago it came to our attention that Rigol’s DS2000-series oscilloscopes were easily unlocked with a few USB commands. We had expected a small microcontroller device would be developed to send these bits to a scope automatically, and we never imagined the final version of this tool hack would be so elegant. Now it’s possible to unlock a DS2072 o’scope using just a serial number and a great encryption hack.

The engineers over a Rigol (bless their hearts) used the same hardware for the $800, 70MHz DS2072 and the $1600, 200MHz DS2202. The only difference between the two are a few bits in the scope’s memory that are easily unlocked if you have the right key. A few folks over on the EEV Blog forum figured out the private key for the scope’s encryption and the user [cybernet] wrote a keygen.

The upgrade process is extremely simple: get the serial number of your DS2072, put it in the keygen, and enter the resulting key into the scope. Reboot, and you have a $1600 scope you bought for half price.

Thermocouple Vacuum Gauge Teardown

We don’t know how [Ben Krasnow] gets his hands on so much cool hardware. This time around is a bit of vintage tech: a thermocouple vacuum gauge.

The part seen above, and represented in the schematic, is the sensor side of things. This is interesting enough by itself. It has an air chamber with an electric heater element in it. When air is present it dissipates the heat, when under vacuum the heat builds and causes the thermocouple to generate some voltage on its connections.

Keep watching his presentation and things get a lot more interesting. The original unit used to measure the sensor is a throwback to the days when everything had sharp corners and if you were running with scissors you’d eventually teach yourself why that’s not such a good idea. The designers were rather cavalier with the presence of mains voltage, as it is barely separated from connections grounding the case itself.

Want to see some of the other cool equipment he’s got on hand? How about a CT scanner he built.

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Resistance Decade Box Using DIP Switches

resistance-decade-box

Here’s a simple piece of equipment which you’ll be proud to display on your electronics bench. It’s a resistance decade box. The concept has been around forever — it offers the ability to tune a wide range of resistance values just by adjusting the controls. We especially like the clean look of this one, and think the use of DIP switches is a nice touch.

Check out the toggle switch at the top. It lets you disconnect the resistance values from the output in order to test them with your meter. It may not seem like much, but fudging your switch settings could end up smoking your target project. The value of that feature isn’t lost on us.

The DIP switches are mounted to some Radio Shack breakout boards which work perfectly for hosting the resistors as well. This keeps the inside of the enclosure nice and tidy. The final touch is the printed face plate applied to the cover of the box.

Like we’ve said, this one is nice but our favorite is still this one that uses thumbwheel switches to dial in a value.

Making PCBs And Waffles

waffle

The toner transfer method of fabricating PCBs is a staple in every maker’s toolbox. Usually, tutorials for this method of making PCBs rely on a clothes iron or laminating machine. They work perfectly well, but with both of these methods (sans high-end laminators), you’re only heating one side of the board at a time, making perfect double-sided PCBs somewhat of a challenge.

[Mark] just came up with an interesting solution to this problem. A waffle iron PCB press. Technically, [Mark] is using his ‘grill and waffle baker’ as a two-sided griddle, with a few aluminum plates sandwiching the copper board for good thermal conduction.

After a whole lot of trial and error, [Mark] eventually got a good transfer onto a piece of copper clad board. Now that he has the process dialed in, it should be a snap to replicate his results with a new project and a new PCB design.

Arduino Oscilloscope At Five Megasamples Per Second

There’s no substitute for a proper oscilloscope on your electronics bench. But unfortunately we still don’t have one of our own. But we’ve got an Arduino board and paired with another IC it can sample an astonishing 5 million cycles per second.

[Bob Davis] has been working on an Arduino based oscillscope for a while now. He keep squeezing more and more performance out of it. A previous version hit 3 megasamples using an AD775 chip. When he added a FIFO buffer chip he was able to squeeze 10-25 megasamples out of it… wow! Unfortunately the output tended to be glitchy.

This version gets rid of the AD775 in favor of a CA3306. Both are analog-to-digital converters but the new circuit is less complex and more reliable. It uses just three capacitors and an external clock to support the IC. Take a look at the video below to see how it performs. He’s outputting a graph of the samples on a small LCD screen. The best part is that since the extra chip is doing the sampling this can be ported to your microcontroller of choice.

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