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May 27 2018

DIY Submersible Aims for Low Cost, Ease of Operation

If you’re like us, a body of water is a source of wonder and awe. The wonder comes from imagining what lies hidden below the surface, and the awe is from the fear of trying to find out and becoming one of those submerged objects on a permanent basis. So if you want to explore the depths in relative comfort and safety, a DIY remotely operated underwater vehicle might be the thing you need to build.

Most ROV builds these days seem to follow more or less similar designs, which is probably because they all share project goals similar to those of [dcolemans]: build something to take a look around under the water, make it easy to operate, and don’t spend a ton of money. To achieve that, he used 1/2″ PVC pipe and fittings to build the frame and painted it yellow for visibility. A dry tube for the electronics was fashioned from 4″ ABS pipe. The positive buoyancy provided by the dry tube is almost canceled out by the water flooding the frame through weep holes and the lead shot ballast stored in the landing skids. Propulsion is provided by bilge pump cartridges with 3D-printed ducted propellers. A nice touch is a separate topside control box with a screen for the ROV’s camera that talks to a regular RC controller, along with simplified controls and automatic station keeping. Check out the recent swimming pool test in the video below.

There’s a lot going on under the sea, and plenty of ways to explore it. You could deploy sensors shaped like clams, zap underwater lice with lasers, or even glide your way to a Hackaday Prize.

May 26 2018

A Oscilloscope For The Nuclear Age

Here at Hackaday, we’re suckers for vintage instruments. More than one of our staffers has a bench adorned with devices spanning many decades, and there’s nothing more we like reading about that excursions into the more interesting or unusual examples. So when a Tweet comes our way talking about a very special oscilloscope, of course we have to take a look! The Tektronix 519 from 1962 has a 1GHz bandwidth, and [Timothy Koeth] has two of them in his collection. His description may be a year or two old, but this is the kind of device for which the up-to-the-minute doesn’t matter.

A modern 1GHz oscilloscope is hardly cheap, but is substantially a higher-speed version of the run-of-the-mill ‘scope you probably have on your bench. Its 1962 equivalent comes from a time when GHz broadband amplifiers for an oscilloscope input were the stuff of science fiction. The 519 takes the novel approach of eschewing amplification or signal conditioning and taking the input directly to the CRT deflection plates. It thus has a highly unusual 125Ω input impedance, and its feed passes through a coiled coaxial delay line to give the trigger circuits time to do their job before going into the CRT and then emerging from it for termination. It thus has a fixed deflection in volts per centimeter rather than millivolts, and each instrument has the calibration of its CRT embossed upon its bezel.

The 519 would not have been a cheap instrument in 1962, and it is no accident that there are reports of many of them coming back to Tek for service with radioactive contamination from their use in Government projects. We can’t help wondering whether the Russian equivalent super-high-speed ‘scope used the same approach, though we suspect we’ll never know.

If vintage Tek is your thing, have a look at their PCB manufacture from the 1960s.

Thanks [Luke Weston] for the tip.

Disaster Area Communications With Cloud Gateways

2017, in case you don’t remember, was a terrible year for the Caribbean and Gulf coast. Hurricane Maria tore Puerto Rico apart, Harvey flooded Houston, Irma destroyed the Florida Keys, and we still haven’t heard anything from Saint Martin. There is, obviously, a problem to be solved here, and that problem is communications. Amateur radio only gets you so far, but for their Hackaday Prize entry, [Inventive Prototypes] is building an emergency communication system that anyone can use. It only needs a clear view of the sky, and you can use it to send SMS messages. It’s the PR-Holonet, and it’s something that’s already desperately needed.

The basis for the PR-Holonet is built around an Iridium satellite modem. To date, satellite communication is the best way to get a message out to the world without any infrastructure. It’ll work in the middle of the Sahara, the depths of the Amazon, and conveniently anywhere that was just hit by a category five hurricane.

Along with the Iridium modem, [Inventive Prototypes] is using standard, off-the-shelf equipment to turn that connection to a satellite network into something any smartphone can use. That means pulling out a Raspberry Pi, of course. But building a project for areas that were recently ravaged by hurricanes is no easy task. The enclosure it the key here, and [Inventive Prototypes] is using some great water-resistant, dust-proof junction boxes, solar panels, and a whole bunch of batteries to keep everything humming along. It’s a great project and something that was desperately needed a year ago.

The HackadayPrize2018 is Sponsored by:

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A Custom Keypad with Vision

A combination of cheap USB HID capable microcontrollers, the ability to buy individual mechanical keys online, and 3D printing has opened up a whole new world of purpose-built input devices. Occasionally these take the form of full keyboards, but more often than not they are small boards with six or so keys that are dedicated to specific tasks or occasionally a particular game or program. An easy and cheap project with tangible benefits to anyone who spends a decent amount of time sitting in front of the computer certainly sounds like a win to us.

But this build by [r0ckR2] takes the concept one step farther. Rather than just being a simple 3×3 keypad, his includes a small screen that shows the current assignments for each key. Not only does this look really cool on the desk (always important), but it also allows assigning multiple functions to each key. The screen enables the user to switch between different pages of key assignments, potentially allowing a different set of hot keys or macros for every piece of software they use.

The case is entirely 3D printed, as are the key caps. To keep things simple, [r0ckR2] didn’t bother to design a full enclosure, leaving all the electronics exposed on the back. Some might think it’s a little messy, but we appreciate the fact that it gives you easy access to the internals if you need to fix anything. Rubber feet were added to the bottom so it doesn’t slide around while in use, but otherwise the case is a pretty straightforward affair.

As for the electronics, [r0ckR2] went with an STM32 “Blue Pill” board, simply because it’s what he had on hand. The screen is a ST7735 1.44 inch SPI TFT, and the keys themselves are Cherry MX Red clones he got off of eBay. All in all, most of the gear came from his parts bins or else was only a couple bucks online.

If you’re looking for something a bit bigger, check out this gorgeous Arduino-powered version, or this far more utilitarian version. Both are almost entirely 3D printed, proving the technology is capable of more than making little boats.

[via /r/functionalprint]

Watch the Honeycomb Clock Gently Track Time

We love clocks here at Hackaday, and so does [John Whittington]. Last year he created this hexagonal honey clock (or “Honock”) by combining some RGB LEDs with a laser-cut frame to create a smooth time display that uses color and placement to display time with a simple and attractive system.

The outer ring of twelve hexagons is essentially the hour hand, similar to analog clock faces: twelve is up, three is directly to the right, six is straight down, and nine is to the left. The inner ring represents ten minutes per hex. Each time the inner ring fills, the next hex (hour) on the outer ring lights up. The whole display is flooded with a minute-long rainbow at noon and midnight. Watch it in action in the video, embedded below.

[John] also posted an imgur gallery for the Honock, with some good shots of the assembly. Unusual clocks are great ways to show off creativity within broad and simple functional constraints; take for example this robotic clock thats draws out the time on demand.

Their Battery is Full of Air

Storing electrical energy is a huge problem. A lot of gear we use every day use some form of battery and despite a few false starts at fuel cells, that isn’t likely to change any time soon. However, batteries or other forms of storage are important in many alternate energy schemes. Solar cells don’t produce when it is dark. Windmills only produce when the wind blows. So you need a way to store excess energy to use for the periods when you aren’t creating electricity. [Kris De Decker] has an interesting proposal: store energy using compressed air.

Compressed air storage is not a new idea. On a large scale, there have been examples of air compressed in underground caverns and then released to run a turbine at a future date. However, the efficiency of this is poor — around 40 to 50 percent — mainly because the air heats up during compression and often needs to be prewarmed (using energy from another source) prior to decompression to prevent freezing. By comparison, batteries can be 70 to 90 percent efficient, although they have their own problems, too.

The idea explored in this paper is not to try to store a power plant’s worth of energy in a giant underground cavern, but rather use smaller compressed air setups like you would use batteries to store power at the point of consumption. The technology is called micro-CAES (an acronym for compressed air energy storage).

Although the article compares them to batteries, they seem more akin to fuel cells, to us, even though the technology is quite different, of course. Batteries usually have a fairly limited lifespan and often produce just a few times the amount of energy required to manufacture them. CAES and fuel cells typically have very long lifespans, so they produce a lot more energy over that lifespan than was used in their construction. There’s nothing very exotic or toxic either. An air storage tank, a compressor and a generator is all you need.

Keep in mind “micro” here is in context of giant underground storage caverns. The article estimates that a system for a typical residence would cost about $10,000. More than batteries, but with a lower total cost over time because batteries wear out. No one is suggesting your laptop or cell phone will run on compressed air.

This sounds great, but there are two major problems. First, the amount of air you have to store to be practical is an issue. The other problem is the system efficiency is low. Worse, these parameters are interrelated. So storing at a higher air pressure to get more air in a particular volume will also reduce efficiency.

The main extra proposal to help make micro-CAES practical is to take advantage of the heat produced on compression to heat water and living space. On decompression, the heat absorbed can be used for air conditioning and refrigeration. This reduces the electric demand for those tasks, making the overall system more efficient. In other words, if you could reduce electric usage by half because of the cooling and heating properties of the micro-CAES, that will offset the low efficiency of the unit.

The other way to possibly make micro-CAES practical is by using low pressure so that there isn’t much heat produced or consumed. You can read all the pros and cons of this approach in the original post.

This is an area of active research around the world. It struck us that this would be an area where a citizen scientist could make a real impact. There’s nothing super exotic about it. Air compressors and tanks are easy to obtain. Generating with a turbine is easily accomplished, too. We have a feeling a little hacker ingenuity could go a long way in making real advances in this area. Your tough choice? Do you publish in a journal or do you submit your work to the Hackaday tip line? We vote for the tip line.

Hackaday Belgrade is On: Join LiveStream and Chat!

Good morning Hackaday universe! Hackaday Belgrade 2018 has just started, and we’re knee-deep in sharing, explaining, and generally celebrating our craft. But just because you’re not here doesn’t mean that you shouldn’t take part.

Come join us!

Wireless Charger Gives a Glimpse into Industrial Design Process

Almost every product on the market has been through the hands of an industrial designer at some point in its development. From the phone in your pocket to the car in your driveway or the vacuum in your closet, the way things look and work is the result of a careful design process. Taking a look inside that process, like with this wireless phone charger concept, is fascinating and can yield really valuable design insights.

We’ve featured lots of [Eric Strebel]’s work before, mainly for the great fabrication tips and tricks he offers, like how to get a fine painted finish or the many uses of Bondo. But this time around, he walks us through a condensed version of his design process for a wireless phone charger and stand. His client had specific requirements, like being able to have the phone held up in landscape or portrait mode, so he started with pen and paper and sketched some ideas. A swiveling cylinder seemed to fit the bill, and after a quick mockup in PVC pipe, he started work on a full-size prototype in urethane foam. There are some great fabrication tips in the video below, mainly centered on dealing with not owning a lathe.

The thing for us with all of [Eric]’s videos, but especially this one, is seeing the design process laid out, from beginning to (almost) the end. He sure makes industrial design look like a cool gig, one that would appeal to the Jacks- and Jills-of-all-trades who hang out around here.

This Robot Barfs Comics!

If there’s one thing that’s more fun than a comic, it’s a randomly generated comic. Well, perhaps that’s not true, but Reddit user [cadinb] wrote some software to generate a random comic strip and then built a robot case for it. Push a button on the robot and you’re presented with a randomly generated comic strip from the robot’s mouth.

The software that [cadinb] wrote is in Processing, an open source programming language and “sketchbook” for learning to code if you’re coming from a visual arts background. The Processing code determines how the images are cropped and placed and what kind of background they get. Each image is hand drawn by [cadinb] and has information associated with it so the code knows what the main focus of the image is. Once the panels are created, the final image is passed on to a thermal printer for printing. Everything is controlled from a Python script running on a Raspberry Pi and the code, strip artwork, and case is all available online to check out.

Now that the comic can print, a case is needed for the printer and controls. [cadinb] designed a case in Illustrator after creating a prototype out of foam core. The design was laser cut and then coloured – the main body with fabric dye and the arms stained with coffee!

Now [cadinb] has a robot that can sit on his table at conventions and a fan can press a button and have a randomly generated comic strip printed out before their eyes! We have a neat article about printing a comic on a strand of hair, and one about bringing the Banana Jr. 6000 to life!

Via Reddit.

USB Reverse Engineering: A Universal Guide

Every hacker knows what it is to venture down a rabbit hole. Whether it lasts an afternoon, a month, or decades, finding a new niche topic and exploring where it leads is a familiar experience for Hackaday readers.

[Glenn ‘devalias’ Grant] is a self-proclaimed regular rabbit hole diver and is conscious that, between forays into specific topics, short-term knowledge and state of mind can be lost. This time, whilst exploring reverse engineering USB devices, [Glenn] captured the best resources, information and tools – for his future self as well as others.

His guide is impressively comprehensive, and covers all the necessary areas in hardware and software. After formally defining a USB system, [Glenn] refers us to [LinuxVoice], for a nifty tutorial on writing a linux USB driver for an RC car, in Python . Moving on to hardware, a number of open-source and commercial options are discussed, including GoodFET , FaceDancer, and Daisho – an FPGA based monitoring tool for analysing USB 3.0, HDMI and Gigabit Ethernet. If you only need to sniff low speed USB, here’s a beautifully small packet snooper from last year’s Hackaday prize.

This is a guide which is well-informed, clearly structured, and includes TL;DR sections in the perfect places. It gives due credit to LibUSB and PyUSB, and even includes resources for USB over IP.

If you’re worried about USB hacks like BadUSB, perhaps you should checkout GoodUSB – a hardware firewall for USB devices.

Header image: Ed g2s (CC-SA 3.0).

 

May 25 2018

Linear Clock is a Different Way to Look at Time

There are usually two broad user interfaces for clocks. On the one hand you’ve got the dial clock, the default display for centuries, with its numbered face and spinning hands. The other mode is some form of digital clock, where the current time is displayed directly as alphanumeric characters. They’re both useful representations of time, but they both have their limits.

Here’s a third model — the linear clock. [Jan Derogee] came up with it thanks to the inspiration of somewhat dubious run-ins with other kinds of clocks; we feel like this introductory video was made with tongue firmly planted in cheek. Whatever the inspiration, we find this idea clever and well executed. The running gear of the clock is just a long piece of M6 threaded rod and a stepper motor. A pointer connected to a nut rides on the rod, moving as the stepper rotates it. There are scales flanking the vertical rod, with the morning hours going up the left side and afternoon hours coming down the right. The threaded rod rotates one way for twelve hours before switching to the other direction; when the rotation changes, the pointer automatically swivels to the right scale. For alarms, [Jan] has brass rods running along each scale that make contact with the pointer; when they encounter a sliding plastic insulator to break the contact, it triggers an alarm. An ESP8266 controls everything and plays the audio files for the alarm.

Unusual clocks seem to be a thing with [Jan]. His other builds include this neat phosphorescent clock and YouTube subs counter, which is sure to turn heads along with this clock.

Don’t Flake on Your Fish—Feed them Automatically

We get it. You love your fish, but they can’t bark or gently nip at your shin flesh to let you know they’re hungry. (And they always kind of look hungry, don’t they?) One day bleeds into the next, and you find yourself wondering if you’ve fed them yet today. Or are you thinking of yesterday? Fish deserve better than that. Why not build them a smart fish feeder?

Domovoy is a completely open-source automatic fish feeder that lets you feed them on a schedule, over Bluetooth, or manually. This simple yet elegant design uses a small stepper motor to drive a 3D-printed auger to deliver the goods. Just open the lid, fill ‘er up with flakes, and program up to four feedings per day through the 3-button and LCD interface. You can even set the dosage, which is measured in complete revolutions of the auger.

It’s built around an ATMega328P, but you’ll have to spin your own board and put the feeder together using his excellent instructions. Hungry to see this feeder in action? Just swim past the break.

Can’t be bothered to feed your fish automatically? Train them to feed themselves.

An Ultrasound Driver With Open Source FPGAs

Ultrasound imaging has been around for decades, but Open Source ultrasound has not. While there are a ton of projects out there attempting to create open ultrasound devices, most of this is concentrated on the image-processing side of things, and not the exceptionally difficult problem of pinging a sensor at millions of times a second, listening for the echo, and running that through a very high speed ADC.

For his entry into the Hackaday Prize, [kelu124] is doing just that. He’s building an ultrasound board that’s built around Open Hardware, a fancy Open Source FPGA, and a lot of very difficult signal processing. It also uses some Rick and Morty references, so you know this is going to be popular with the Internet peanut gallery.

The design of the ultrasound system is based around an iCE40 FPGA, the only FPGA with an Open Source toolchain. Along with this, there are a ton of ADCs, a DAC, pulsers, and a high voltage section to drive the off-the-shelf ultrasound head. If you’re wondering how this ultrasound board interfaces with the outside world, there’s a header for a Raspberry Pi on there, too, so this project has the requisite amount of blog cred.

Already, [kelu] has a working ultrasound device capable of sending pulses out of its head and receiving the echo. Right now it’s just a few pulses, but this is a significant step towards a real, working ultrasound machine built around a reasonably Open Source toolchain that doesn’t cost several arms and legs.

The HackadayPrize2018 is Sponsored by:

Microchip

Digi-Key

Supplyframe

Biasing That Transistor: The Emitter Follower

We were musing upon the relative paucity of education with respect to the fundamentals of electronic circuitry with discrete semiconductors, so we thought we’d do something about it. So far we’ve taken a look at the basics of transistor biasing through the common emitter amplifier, then introduced a less common configuration, the common base amplifier. There is a third transistor amplifier configuration, as you might expect for a device that has three terminals: the so-called Common Collector amplifier. You might also know this configuration as the Emitter Follower. It’s called a “follower” because it tracks the input voltage, offering increased current capability and significantly lower output impedance.

The emitter follower circuit The emitter follower circuit

Just as the common emitter amplifier and common base amplifier each tied those respective transistor terminals to a fixed potential and used the other two terminals as amplifier input and output, so does the common collector circuit. The base forms the input and its bias circuit is identical to that of the common emitter amplifier, but the rest of the circuit differs in that the collector is tied to the positive rail, the emitter forms the output, and there is a load resistor to ground in the emitter circuit.

As with both of the other configurations, the bias is set such that the transistor is turned on and passing a constant current that keeps it in its region of an almost linear relationship between small base current changes and larger collector current changes. With variation of the incoming signal and thus the  base current there is a corresponding change in the collector current dictated by the transistor’s gain, and thus an output voltage is generated across the emitter resistor. Unlike the common emitter amplifier this voltage increases or decreases in step with the input voltage, so the emitter follower is not an inverting amplifier.

The keen-eyed reader will have noticed at this point that since the base-emitter junction of a transistor is also a diode, it will always maintain approximately the same voltage across itself regardless of the current flowing within it. For a silicon transistor, this is around 0.6 V so the output voltage on the emitter will always be 0.6 V lower than the input voltage on the base. Thus the voltage gain of an emitter follower will always be just a tad less than 1, and you might thus expect that it would therefore be of little use as an amplifier if you neglected that it has significant current gain. The output impedance of an emitter follower is significantly lower than that of a common emitter amplifier, allowing it to drive much more demanding loads. You will often find it used as a buffer stage for this reason, and a handy example can be found on the output of an early op-amp we took a look at earlier in the year.

We’ve now taken a look at the three basic configurations of a transistor amplifier, as well as the fundamentals of biasing a bipolar transistor. It might seem odd to cover this topic on Hackaday when it’s certain that many of you are already familiar with it, but sometimes it’s worth remembering that not everybody is fortunate enough to he well-versed in these fundamentals. The impetus for this series came from a friend lamenting that while his pupils had advanced knowledge of microcontrollers that his generation hadn’t acquired as their age, they had not been given the opportunity to learn these fundamentals.

There is one final piece to come on this topic, these same principles apply to the other three-terminal active components, so we’ll have a quick look at FETs and tubes.

Hacking for Learning and Laughs: The Makers of Oakwood School

The tagline of Bay Area Maker Faire is “Inspire the Future” and there was plenty of inspiration for our future generation. We have exhibits encouraging children to get hands-on making projects to call their own, and we have many schools exhibiting their student projects telling stories of what they’ve done. Then we have exhibitors like Oakwood School STEAM Council who have earned a little extra recognition for masterfully accomplishing both simultaneously.

[Marcos Arias], chair of the council, explained that each exhibit on display have two layers. Casual booth visitors will see inviting hands-on activities designed to delight kids. Less obvious is that each of these experiences are a culmination of work by Oakwood 7th to 12th grade students. Some students are present to staff activities and they were proud to talk about their work leading up to Maker Faire with any visitors who expressed interest.

In one activity, visitors build their own tippe top. Each person pulls a 3D-printed body from inventory, performs surface finishing work with sandpaper, and install a wooden dowel stem followed by optional decorations with color markers. This simple build is accessible to a wide spectrum of audiences and provides immediate satisfaction with a fun toy. But how was the tippe top’s body shape determined? They did not just download something online. The profile was generated by students working and iterating through many ideas satisfying the requirement — fits within a volume of 30 cm³ — while maximizing their evaluation metric — flips over fastest and remains spinning upright longest. Once a winning design was chosen, it was printed at quantity to star in this activity at Maker Faire.

Another activity invites visitors to build a gravity racer. Just like the tippe top activity, the design actually built by Maker Faire attendees is the winning design from Oakwood students who worked to find the best shape to meet the challenge. Builders at the faire can customize their own racer during assembly from provided parts, then two racers can compete side by side on a long track to see how well their racer worked.

Chair [Marcos Arias] steers Oakwood’s STEAM program with the North Star of “Play to Passion to Purpose.” It was fascinating to hear about the work behind these and other fun Maker Faire activities. We can rest assured that creative problem-solving hacker spirit is nurtured at such schools to inspire our hackers of the future.

Hacking When It Counts: The Pioneer Missions

If the heady early days of space exploration taught us anything, it was how much we just didn’t know. Failure after failure mounted, often dramatic and expensive and sometimes deadly. Launch vehicles exploded, satellites failed to deploy, or some widget decided to give up the ghost at a crucial time, blinding a multi-million dollar probe and ending a mission long before any useful science was done. For the United States, with a deadline to meet for manned missions to the moon, every failure in the late 1950s and early 1960s was valuable, though, at least to the extent that it taught them what not to do next time.

For the scientists planning unmanned missions, there was another, later deadline looming that presented a rare opportunity to expand our knowledge of the outer solar system, a strange and as yet unexplored wilderness with the potential to destroy anything humans could build and send there. Before investing billions in missions to take a Grand Tour of the outer planets, they needed more information. They needed to send out some Pioneers.

A Grand Tour on the Back of Orbital Mechanics

Even before the time of Kepler and Newton, the orbits of the planets had been well characterized, and astronomers were well aware that a planetary alignment would occur in the late 1970s that would allow a single spacecraft to visit each of the outer planets. After exploring Jupiter, the probe would use the gas giants’ gravity to fling it on to Saturn, then to Neptune, and then out of the Solar System. Such an alignment happens only once every 175 years, and it was too good to pass up.

But humanity hadn’t yet reached beyond the inner planets, and there were many questions. Would the asteroid belt prove an impenetrable barrier? Would Jupiter’s powerful radiation belts cook any probe that came close to it? And how would we communicate with a probe that far away? These questions and more presented unacceptable risks to a mission that would cost in the billions of dollars, and they needed to be answered before committing to a Grand Tour mission.

First proposed in 1964 as a “Galactic Jupiter Probes” and approved by NASA in 1969, what would come to be known as Pioneer 10 and Pioneer 11 would answer these questions. The idea was to build small, lightweight probes that would take advantage of favorable launch windows 13 months apart in 1972 and 1973. Each probe would carry just enough instrumentation to provide the data needed to plan the Grand Tour mission that would launch in 1977 as the Voyager program.

Pioneer 11. Source: Honeysuckle Creek Tracking Station

By space program standards, both the mission and the Pioneer spacecraft were full of hacks. Pioneer 10 would visit only Jupiter to get the critical data before heading off into deep space. Pioneer 11 would continue on to Saturn, assuming either probe survived the asteroid belt, where no probe had gone before.

The spaceframe for the probes was simple and lightweight, leveraging previous probes from the Pioneer program. It consisted of a dish antenna as large as the Atlas-Centaur launch vehicle, left over from the Mercury manned program, would allow. To reduce weight and cost, the Pioneer spacecraft would be spin-stabilized, reducing the amount of maneuvering fuel it had to carry. NASA lucked out on power for the probes, using radioisotope thermal generators (RTGs) that were given to the program by the Atomic Energy Commission. The devices only provided an energy budget of about 155 watts at launch, though, so instrumentation had to be carefully selected.

The limited energy budget meant NASA had to make some tradeoffs, though, and the biggest of these was to not include a computer onboard, at least not in the traditional sense. There was a tiny amount of memory on board, about 6-kB, which was just enough to store five commands uplinked from Earth. But everything the spacecraft would need to do would be commanded from the ground over the Deep Space Network (DSN), taking into account the 90 minute round trip when the machines were at Jupiter.

Pix or it Didn’t Happen

How the Imaging Photopolarimeter (IPP) took pictures. Source: NASA History Program Office

In the same way that we tend to take heat from social media friends if we don’t post pictures from a vacation, NASA was not going to get away with not sending back pictures from across the Solar System. But cameras and the gear needed to digitize, record, and transmit the data are bulky and energy-hungry, so mission planners had to be especially clever about a solution. They decided to take advantage of the spin-stabilization of Pioneer, using the 4.8 RPM rotation as a way to optically scan Jupiter as it approached the gas giant. The Imaging Photopolarimeter instrument was put to use as a one-pixel camera, sweeping off one scan for every rotation of the craft and changing the angle of the sensor slightly after each scan. Each scan was done twice, once with a red filter and once with blue, and the data was sent to the ground for extensive manipulation, including adding a false green channel.

Up close and personal with Jupiter. Source: NASA History Program Office

Despite the low-budget nature of the design, Pioneer managed to pack a lot of science on board, from cosmic ray detectors, to magnetometers, to the crucial micrometeoroid detectors used to analyze the risks of crossing the debris-strewn asteroid belt. That last instrument was a simple affair as well, with an array of cells pressurized with gas; any impact strong enough to burst a cell could be detected by the loss of pressure.

Pioneer 10 launched on March 2, 1972; Pioneer 11 followed 13 months later. After a 20-month journey, Pioneer 10, having survived what turned out to be the not-so-dangerous asteroid belt, arrived at Jupiter. It survived the onslaught of Jovian radiation, sending back data and pictures as it gained speed in Jupiter’s gravity well. The spacecraft performed flawlessly, flinging itself around the planet and providing humanity’s first look at a crescent outer planet as it achieved solar escape velocity and became the first interstellar spacecraft.

Aware of this fate, the Pioneer team had affixed the then-controversial but now-famous Pioneer Plaque to the spacecraft, bearing images of the spacecraft, figures representing the species that built it, and data to show where and when the craft was launched, in the unlikely event that it would ever be found by another spacefaring race.

Into the Void

The Pioneer Plaque. Source: NASA

The Pioneer program was immensely successful, despite — or perhaps because of — its limited scope and budget. The Voyager probes, vastly more complicated and capable spacecraft, would be launched in 1977 and visit Jupiter, Saturn, Uranus, and Neptune with stunning images and torrents of data that scientists are still poring through, piecing together a picture of the outer Solar System before joining the Pioneers in interstellar space.

Both Pioneers long ago went silent, their RTGs finally having degraded to uselessness. Voyager still lives on, but what it accomplished was only because Pioneer paved the way.

Many thanks to [J.R. Dahlman] for the inspiration for this article, and the suggestion to read The Depths of Space: The Story of the Pioneer Planetary Probes by Mark Wolverton.

NASA Remotely Hacks Curiosity’s Rock Drill

We have a lot of respect for the hackers at NASA’s Jet Propulsion Laboratory (JPL). When their stuff has a problem, it is often millions of miles away and yet they often find a way to fix it anyway. Case in point is the Curiosity Mars rover. Back in 2016, the probe’s rock drill broke. This is critical because one of the main things the rover does is drill into rock samples, collect the powder and subject it to analysis. JPL announced they had devised a way to successfully drill again.

The drill failed after fifteen uses. It uses two stabilizers to steady itself against the target rock. A failed motor prevents the drill bit from retracting and extending between the stabilizers. Of course, sending a repair tech 60 million miles is not in the budget, so they had to find another way. You can see a video about the way they found, below.

NASA calls what happened “MacGyvering.” The drill bit is fully extended at all times. Now the rover has to use the entire arm to push the drill forward and recenter without the stabilizers. The arm has a force sensor made to detect if the arm strikes something. That sensor now has a new purpose, to monitor the progress of the drilling.

There’s still one more piece of the puzzle to solve. Since the drill no longer retracts, it can’t deliver the payload of rock powder to the onboard laboratories. Since the drill has a percussion mechanism, they’ve figured out a way to “tap out” the powder in their mockup here on Earth. They’ll be testing how well it works on Mars soon. If we were gamblers, we’d bet they will figure it out.

Bringing a VIC-20 Back from an Oily Grave

No matter which platform you’re into, retrocomputing is usually a labor of love. The obsolete, the unpopular, the downright weird – old computers of every stripe are found, restored to something like their former glory, and given a new lease on life. It’s heartwarming, in a way. But when a computer has obviously been abused, it takes a little extra effort, of a lot in the case of this oil-submerged VIC-20 restoration.

In the two-part video below, [The 8-Bit Guy] goes through the gory details of bringing this classic Commodore back from the grave. The first video shows the cosmetic rebuild, which given the filthy state of the machine was no mean feat. Cracked open, the guts were found to be filled with an oily residue; [The 8-Bit Guy] chalks that up to a past life in some kind of industrial setting, but we see it more as flood damage. Whatever the sad circumstances on the machine’s demise, the case required a workout to clean up, and it came out remarkably fresh looking. The guts needed quite a bit of cleaning too, mainly with brake cleaner to cut through the gunk.

Part two focuses on getting the machine running again, and here [The 8-Bit Guy] had his work cut out as well. With a logic probe, signal injector, and some good old-fashioned chip swapping, he was able to eliminate most of the potential problems before settling in on some RAM chips as culprits for the video problems he saw at power-up. It all worked out in the end, and the machine looks and acts like new. We’re impressed.

Maybe we shouldn’t question [The 8-Bit Guy]’s call on the VIC-20 being from an industrial setting, though. After all, the “little Amiga that could” ran a school’s HVAC system for over 30 years.

Rey’s Blaster Shoots Glow-in-the-Dark Bullets

Youtuber and rubber band enthusiast [JoergSprave] is a big fan of Star Wars, and he loved the look of the blaster that Han Solo gave to Rey. He’d seen a few replicas of Rey NN-14 gun, but hadn’t seen any that actually fired anything, so he set out to make one that did.

The build itself is from plywood, with a paint job to make it look like an old blaster. What makes the build really cool is the bullets used: glow sticks! [Joerg] created space in the magazine for three glow sticks, so you’ve got a couple of shots before you have to reload. Crack ’em, load them up and then fire away!

The glow sticks give the blaster fire a great look (especially in the dark!) and it’s really easy to find the shots after you’ve fired them. We’ve featured [Joerg]’s builds a few times on the site, and his build videos are a lot of fun. Check out his compressed air crossbow bolt gatling gun, or his machete shooting slingshot.

Ears To You: Sensing Facial Expressions with an Ear Plug

Electronics keep getting smaller, but human fingers don’t. This leads to a real challenge with highly-embedded wearable computers. Sure, voice command has come a long way, but it has its own challenges. You might not want to verbally command your Borg implants in some situations. Maybe you need to be quiet. Or perhaps you are worried about accidentally triggering the device. Researchers in Germany want to monitor facial expressions instead. So to snap a picture, you might wink and to fast forward your movie playing on the inside of your eyelids, perhaps you’d look to the right twice. You can see a video presentation about the paper, below.

The paper looks at several different methods to read facial movements. Some were pretty intrusive. However, a promising technique used Ear Field Sensing (EarFS). An earplug with an electrode senses electrical changes in the ear canal resulting from facial muscle movement. Other techniques examined included electromyography, capacitive sensing, and a different form of electrical field sensing.

The team identified 25 different facial expressions, although they settled on the best five for each technology. It seems that people start forgetting what to do as the command list passes beyond about seven gestures.

The circuit to sense the ear was created in Eagle, and appears in the paper. There are some very high resistances involved along with an instrumentation amplifier and two dual op amps. The circuit has a few options for working single-ended or differential with different filters. Amusingly, for testing the researchers stuck a pinky in their ears to feel what the various facial expressions did inside the ear canal.

Testing with the devices included in a static setting and while in motion. None of the technologies were perfect, but the data does show that it is possibly useful if you could miniaturize and package the circuits in a more consumer-friendly fashion.

We thought about using OpenCV to look at facial expressions, but while that’s one thing for a robot, it would be hard to do with a device you were wearing. We wonder if this technique would be less useful for command and more useful for figuring out how ticked off you were.

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