In the latest issue of the Recomendo newsletter, my friend and colleague Claudia Dawson wrote about Oldestsearch.com a site that t"reverse-orders all Google search results so that you see the oldest webpages first. This is refreshing to use, because I so often feel like all the top results are repetitive." — Read the rest
NASA's James Webb Space Telescope is now perfectly aligned, as evidenced by this absolutely incredible image of the Large Magellanic Cloud, a satellite galaxy of our Milky Way that is around 160,000 light years away from Earth. Below, compare the new image with the previous one captured by NASA's Spitzer Space Telescope. — Read the rest
Electric vehicles are now commonplace on our roads, and charging infrastructure is being built out across the world to serve them. It’s the electric equivalent of the gas station, and soon enough, they’re going to be everywhere.
However, it raises an interesting problem. Gas pumps simply pour a liquid into a hole, and have been largely standardized for quite some time. That’s not quite the case in the world of EV chargers, so let’s dive in and check out the current state of play.
AC, DC, Fast, or Slow?
Since becoming more mainstream over the past decade or so, EV technology has undergone rapid development. With most EVs still somewhat limited in range, automakers have developed ever-faster charging vehicles over the years to improve practicality. This has come through improvements to batteries, controller hardware, and software. Charging tech has evolved to the point where the latest EVs can now add hundreds of miles of range in under 20 minutes.
However, charging EVs at this pace requires huge amounts of power. Thus, automakers and industry groups have worked to develop new charging standards that can deliver high current to top vehicle batteries off as quickly as possible.
As a guide, a typical home outlet in the US can deliver 1.8 kW of power. It would take an excruciating 48 hours or more to charge a modern EV from a home socket like this.
In contrast, modern EV charge ports can carry anywhere from 2 kW up to 350 kW in some cases, and require highly specialized connectors to do so. Various standards have come about over the years as automakers look to pump more electricity into a vehicle at greater speed. Let’s take a look at the most common options out in the wild today.
“Type 1” aka SAE J1772
AC, single phase.
The SAE J1772 standard was announced in June 2001, also known as the J Plug. The 5-pin connector supports single-phase AC charging at 1.44 kW when hooked up to a standard home power socket, ramping up to a full 19.2 kW when installed on a higher-speed EV charging station. The connector carries single-phase AC power on two conductors, signalling on two further conductors, with the fifth being a protective earth connection.
The J Plug became mandatory for all EVs sold in California after 2006, and quickly caught on in the USA and Japan, with some penetration into other worldwide markets.
“Type 2” aka Mennekes
AC, single or three phase.
The Type 2 connector, also known for its creator, German manufacturer Mennekes, was first proposed in 2009 as a replacement for SAE J1772 in the European Union. It’s headline feature is that its 7-pin connector design can carry single-phase or three-phase AC power, allowing it to charge vehicles with at up to 43 kW. In practice, many Type 2 chargers top out at 22 kW or less. It similarly features two pins for signalling pre-insertion and post-insertion, similar to J1772. It then has a protective earth, a neutral, and three conductors for the three AC phases.
In 2013, the EU chose Type 2 plugs as the new standard to replace J1772 and the obscure EV Plug Alliance Type 3A and 3C connectors in AC charging applications. The connector has become widely accepted the European market since then, and is available on many international market vehicles, too.
CCS – Combo 1, Combo 2
AC, single or three phase, DC fast charging
CCS stands for Combined Charging System, and uses “combo” connectors to allow both DC and AC charging. The standard was published in October 2011, and aimed to allow for high-speed DC charging to be easily implemented on new vehicles. This would be achieved by adding a pair of DC conductors to existing AC connector types. CCS comes in two main forms, the Combo 1 connector and the Combo 2 connector.
The Combo 1 features a Type 1 J1772 AC connector paired with two large DC conductors. Thus, a vehicle with a CCS Combo 1 connector can hook up to J1772 chargers for AC charging, or a Combo 1 connector for high-speed DC charging. This design was intended for vehicles on the US market, where the J1772 connector had become commonplace.
The Combo 2 connector features a Mennekes connector paired with two large DC conductors. Intended for the European market, this allows cars with a Combo 2 socket to charge on single or three phase AC with a Type 2 connector, or to hook up to a Combo 2 connector for DC fast charging.
CCS allows for AC charging as per the standards of either the J1772 or Mennekes subconnectors built into the design. When used for DC fast charging, however, it allows for lightning-fast charge rates up to 350 kW.
Notably, DC fast chargers with the the Combo 2 connector eliminate the AC phase connections and neutral from the connector, as they are unneeded. Combo 1 connectors leave them in place, though they are unused. Both designs rely on the same signalling pins as used by the AC connector in order to communicate between vehicle and charger.
AC single or three phase, DC fast charging
As one of the pioneering companies in the EV space, Tesla set out to design its own charging connector to suit the needs of its vehicles. This was rolled out as part of Tesla’s Supercharger network, which aimed to build out a fast-charger network to support the company’s vehicles when little other infrastructure existed for the purpose.
While the company fits its vehicles with Type 2 or CCS connectors in Europe, in the US, Tesla has used its own charge port standard. It can support both AC single and three phase charging, as well as the high-speed DC charging at Tesla’s Supercharger stalls.
Tesla’s original Supercharger stations could deliver up to 150 kW per car, though later low-power models for urban areas had a lower limit of 72 kW. The company’s latest chargers can deliver up to 250 kW to suitably equipped vehicles.
Chinese GB/T 20234.3 Standard
DC fast charging
Issued by the Standardization Administration of China, the GB/T 20234.3 standard covers a connector capable of both single-phase AC and DC fast charging. Virtually unknown outside China’s unique EV market, it’s rated to run at up to 1,000V DC and 250 amps, providing charging speeds up to 250 kW.
It’s unlikely you’d find this port on a vehicle that wasn’t built in China, and intended for its own market or perhaps those countries it has strong trade relationships with.
Perhaps most interesting about this port design are the A+ and A- pins. These are rated for up to 30 V and up to 20 A of current. They’re described in the standard as being for “low voltage auxiliary power supply provided by the off-board charger for the electric vehicle.”
Their exact function isn’t clear from that translation, but they may be intended to help jump-start an EV that has completely dead batteries. When an EV’s traction battery and 12V battery are both dead, it can be difficult to charge the vehicle as the car’s electronics don’t have any power to wake up and communicate with the charger. Nor can contactors be energized to connect the traction pack to the car’s various subsystems. These two pins may be intended to provide enough juice to run the car’s basic electronics and energise contactors so that the main traction battery can be charged even if the vehicle has absolutely no power. If you know more about this, feel free to let us know in the comments.
DC fast charging
CHAdeMO is a connector standard for EVs that was built first and foremost for fast-charging applications. It can deliver up to 62.5 kW via its unique connector. It was the first standard that aimed to provide DC fast charging to EVs regardless of manufacturer, and features CAN bus pins for communication between vehicle and charger.
The standard was proposed in 2010 for global use, backed by Japanese automakers. However, the standard has only really caught on in Japan, with Europe sticking to Type 2 and the US going with J1772 and Tesla’s own connector. The EU at one point considered mandating a complete phase-out of CHAdeMO chargers, but instead settled for a requirement that charging stalls “at least” feature a Type 2 or Combo 2 connector instead.
A backwards-compatible upgrade was announced in May 2018, which would allow CHAdeMO chargers to deliver up to 400 kW, eclipsing even CCS connectors in this area. Proponents of CHAdeMO cited its nature as a single standard around the globe, versus the split between US and EU CCS standards. However, it has failed to find much purchase outside the Japanese market.
A CHAdeMo 3.0 standard has been in development since 2018. Known as ChaoJi, it features a completely new 7-pin connector design, developed in partnership with the Standardization Administration of China. It hopes to increase charging rates up to 900 kW, running at 1.5 kV and delivering a full 600 amps through the use of liquid-cooled cabling.
Reading this article, you could be forgiven for thinking that there’s a whole mess of different charging standards ready to give you headaches wherever you drive your new EV. Thankfully, it’s not really the case. Most jurisdictions have worked to support one charging standard to the exclusion of most others, leading to most vehicles and chargers in a given area all being compatible. The exception, of course, is Tesla in the US, but they also have their own dedicated charging network.
While there are a few people that have gotten stuck with the wrong charger in the wrong place at the wrong time, they can often get by with an adapter of some sort or other where needed. Going forward, most new EVs are sticking to the established charger types in their region of sale, making life easier for everyone.
The average Hackaday reader should be familiar with the concept of determining the distance of a faraway object by measuring how long it takes a sound or radio wave to be reflected, such as in sonar and radar. Going another step and measuring Doppler Shift – the difference in the returned signal’s frequency – will tell us the velocity of the object relative to our position. It’s so simple that an Arduino can do it. But in the days of Apollo, there was no Arduino. In fact, there were no Integrated Circuits. And Apollo missions went all the way to the moon- far too distant for relatively simple Radar measurements.
How could range (distance), position, and speed then be measured? The answer is one that [Ken] aptly describes as fractal: Each layer of complexity hides beneath it another layer of complexity. Using equations dating from 3rd century China as well as cutting edge weak signal telemetry, Apollo engineers devised a complex but workable system that used an S-Band transponder to take data transmitted from a powerful ground station and send it back on another frequency. One great hack was to use Phase Modulation to encode the downlink instead of Frequency Modulation so that Doppler data gained on the uplink wouldn’t be lost on the downlink.
By knowing the precise position of the ground station and the very large parabolic antennae, not only could the distance and speed be measured, but a good estimation of the spacecraft’s position in 3d space could also be had.
From the use of delay line memory to aggregate weak signals to a state machine computer made up of discrete transistor logic, all the way to the cutting edge transponder on the Command Module, the Apollo digital ranging system is an excellent example of great hacks coming out of a program with tight technical constraints.
84 years ago, a teenager built a TV set in a basement in Hammond, Indiana. The teen was a radio amateur, [John Anderson W9YEI], and since it was the late 1930s the set was a unique build — one of very few in existence built to catch one of the first experimental TV transmitters on air at the time, W9XZV in Chicago. We know about it because of its mention in a 1973 talk radio show, and because that gave a tantalizing description it’s caught the interest of [Bill Meara, N2CQR]. He’s tracking down whatever details he can find through a series of blog posts, and though he’s found a lot of fascinating stuff about early TV sets he’s making a plea for more. Any TV set in the late ’30s was worthy of note, so is there anyone else out there who has a story about this one?
The set itself was described as an aluminium chassis with a tiny 1″ CRT, something which for a 1930s experimenter would have been an expensive and exotic part. He’s found details of a contemporary set published in a magazine, and looking at its circuit diagram we were immediately struck by how relatively simple the circuit of an electrostatically-deflected TV is. Its tuned radio frequency (TRF) radio front end is definitely archaic, but something that probably made some sense in 1939 when there was only a single channel to be received. We hope that [Bill] manages to turn up more information.
If you’re an experienced hacker, you’ve probably run into a problem at some point and thought “let’s make a tool to automate that”. A few hours later you’ve got your tool, but then realize that the amount of work you put into making the tool vastly exceeds what you would have needed to solve the original problem manually. That really doesn’t matter though: developing a fancy tool can be a rewarding experience that teaches you way more about the original problem than you would have learned otherwise. [sjm4306]’s ATtiny High Voltage Fuse Reset-er is a clever device that firmly falls into this category.
The problem it solves is familiar to anyone who’s ever worked with Atmel/Microchip’s ATtiny series of microcontrollers: set one of the configuration fuses incorrectly and you’re no longer able to reprogram your chip. Getting the ATtiny back to its original configuration requires a high-voltage programming step that involves pulling the reset pin to 12 V in what’s otherwise a 5 V system. You could simply grab a spare 12 V supply and hack together a level shifter with a few transistors, but where’s the fun in that?
[sjm4306]’s solution is built on a pretty purple PCB that contains an ATmega328, an OLED display, and sockets to accommodate various versions of the ATtiny series microcontrollers. To generate the required 12 V, one could simply use an off-the-shelf boost converter IC. But instead, he decided it would be interesting to make such a circuit out of discrete components and control it using the ATmega. After all, this chip already contains timers to generate PWM signals and an ADC to measure the converter’s output voltage, so all it took was to write some control logic in the form of a PID controller.
The end result, as you can see in the video embedded below, is a convenient little PCB that runs off a 5 V USB power supply and resets the fuses on your ATtiny at the push of a button. Sometimes, simple tools that do one thing well are all you need; however, if you’re looking for an all-in-one AVR programmer that also supports HV programming, check out this AVR Multi-Tool.