Monoprice Mini Delta Review

For the last year or so, Monoprice has been teasing their follow-up to the fantastic $200 MP Select Mini. This is the $150 mini delta printer. We got a look at it last January at CES, it was on display at the Bay Area Maker Faire last May. Now there’s one on the Hackaday review desk.

Over the last few years, 3D printing has settled down into what most of us expected way back in 2010. No, not everyone wants, or arguably needs, a 3D printer on their desks. This is a far cry from the hype of a few years ago, leaving us with what we have today. 3D printers are just tools, much like a drill press or a laser cutter.

With that said, there still are some fantastic advances in 3D printing coming down from on high. Prusa will be shipping the 4-color multi-extruder add-on for the i3 Mk 2 shortly, and somehow or another we have infinite build volume printers. Still, there’s space to democratize 3D printing, and an opportunity for someone to release a very cheap, very good printer.

Monoprice was kind enough to send me a review unit of the MP Mini Delta before it officially hit their website. This is one of the first off the production line, alongside the few hundred pre ordered on an Indiegogo campaign earlier this year.  Does this printer live up to expectations? It sure does, and that’s not just because it’s a $150 printer.

This would be an excellent printer at three times the price, and evidence enough that 3D printing is changing from a weird hobbyist thing to a proper tool.

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Retrotechtacular: Olivetti Net3

If you sign up for a European hacker camp such as CCC Camp in Germany or SHA Camp in the Netherlands, you’ll see among the items recommended to take with you, a DECT handset. DECT, or Digital Enhanced Cordless Telecommunications, refers to the set of standards that lie behind the digital cordless telephones that are ubiquitous across Europe and some countries elsewhere in the world. These standards cover more than just the simple two-way telephone calls through a base station that most Europeans use them for though, they define a fully functional multi-cell 3G phone and data networking system. This means that an event like SHA Camp can run its own digital phone network without having to implement cell towers.

Olivetti promotional net3 image
Olivetti promotional Net3 image

Reading the history of DECT, there is the interesting snippet that the first DECT product on the market in 1993 was not a telephone but a networking device, and incidentally the first wireless LAN product on the European market. Olivetti’s Net3 provided 512kB/s wireless networking to a base station with Ethernet or Token Ring interfaces for connection to a LAN. In its original form it was an internal card for a desktop PC coupled to a bulky external box containing radio circuitry and antenna, but its later incarnations included a PCMCIA card with a much smaller antenna box. The half-megabit speed seems tiny by today’s standards, but in the pre-multimedia world of 1993 would have been perfectly adequate for a Novell Netware fileserver and an HP Laserjet 4.

Heinz Wolff swallows a condom in another Olivetti promotional picture.
[Heinz Wolff] swallows a condom in another Olivetti promotional image.

Mystery Technology

So DECT is an interesting technology that can do more than just a simple cordless phone, and its first product was unexpectedly somewhat groundbreaking. It then becomes even more interesting to find that Net3 has left very little evidence of itself to find that can be found on the Web, and learning more about it requires a little detective work.

The Wikipedia entry has the bare bones, but it speaks volumes about the obscure nature of the product that the encyclopedia’s only picture of it is a tiny thumbnail-sized promotional image of the PCMCIA variant in a chunky mid-1990s laptop. A further search reveals a 1993 British Olivetti staff newsletter (PDF) carrying another promotional image of the desktop Net3 device featuring the then-well-known TV personality and academic [Heinz Wolff] demonstrating the technology bizarrely by swallowing a DECT medical instrumentation transponder wrapped in a condom. Some press releases remain in the fossilized remnants of the 1990s internet, and a Net3 design team member’s LinkedIn page led us to the patent covering the system, but that’s pretty much it. We can’t even find a high enough resolution image of a Net3 card for our featured image slot.

Wireless Things Before Their Time

It’s obvious that Net3 and DECT networking as a high-end wireless LAN before a need for wireless LANs existed never made it, but what is perhaps more interesting is that it seems to have left no legacy for other more mundane applications. We are in the midst of an explosion of hype around the Internet of Things and it seems new short-range wireless networking technologies appear almost daily, yet the world seems to have overlooked this robust, low power, and mature wireless network with its own dedicated frequency allocation that many of us already have in our homes. It seems particularly surprising that among the many DECT base stations on sale at your local consumer electronics store there are none with an Internet connection, and there is no market for IoT devices that use DECT as their backhaul.

In the open-source community there has been some work on DECT. The OsmocomDECT project for example provides a DECT software stack, and states an aim to “better understand DECT and its security and to create an Open Source implementation of the DECT standard”. But there seems to have been very little hardware work in our community on the standard, for example there are no DECT-specific projects on

Net3 then was a product before its time, a herald of what was to come, from that twilight period when the Web was definitely a thing but had yet to become the world’s universal information repository. Public wireless networking was still several years in the future, so there was no imperative for road warriors to equip themselves with a Net3 card or for computer manufacturers — not even Olivetti themselves! — to incorporate the technology. It thus didn’t take the world by storm, and unusually for such a ground-breaking computer product there remains little legacy for it beyond a rarely-used feature of the protocol Europeans use for their cordless phones.

Did you have a Net3 card? Do you still have one? Let us know in the comments.

Eclipse 2017: Was Einstein Right?

While most people who make the trek to the path of totality for the Great American Eclipse next week will fix their gazes skyward as the heavenly spectacle unfolds, we suspect many will attempt to post a duck-face selfie with the eclipsed sun in the background. But at least one man will be feverishly tending to an experiment.

On a lonely hilltop in Wyoming, Dr. Don Bruns will be attempting to replicate a famous experiment. If he succeeds, not only will he have pulled off something that’s only been done twice before, he’ll provide yet more evidence that Einstein was right.

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Wideband Woes and the Junkbox Miata

As ever, I am fighting a marginally winning battle against my 1991 Mazda MX-5, and this is the story of how I came to install a wideband oxygen sensor in my Japanese thoroughbred. It came about as part of my ongoing project to build myself a viable racecar, and to figure out why my 1990s Japanese economy car engine runs more like a late 1970s Malaise-era boat anchor.

I’ve always considered myself unlucky. My taste for early 90s metal has meant I’ve never known the loving embrace of OBD-2 diagnostics, and I’ve had to make to do with whatever hokey system was implemented by manufacturers who were just starting to produce reliable fuel injection systems.

Narrowband oxygen sensor voltage output. The output is heavily dependent on sensor temperature and highly non-linear, making these sensors unsuitable for delivering a true AFR reading.

This generally involves putting in a wire jumper somewhere, attaching an LED, and watching it flash out the trouble codes. My Mazda was no exception, and after putting up with a car that was running rich enough to leave soot all over the rear bumper, I had to run the diagnostic.

It turned up three codes – one for the cam angle sensor, and two for the oxygen sensor. Now, a cam angle sensor (CAS) fault will normally prevent the car running at all, so it’s safe to assume that was an intermittent fault to keep an eye on.

The oxygen sensor, however, was clearly in need of attention. Its job is to allow the engine control unit (ECU) to monitor the fuel mixture in the exhaust, and make sure it’s not too rich or too lean. As my car was very obviously running too rich, and the diagnostic codes indicated an oxygen sensor failure, a repair was in order.

I priced up replacement sensors, and a new oxygen sensor could be had for under $100. However, it wasn’t exactly what I wanted, as not all oxygen sensors are created equal. Cars in the 80s and 90s typically shipped from the OEM fitted with what’s called a narrowband oxygen sensor. These almost always consist of a zirconia dioxide cell that outputs a voltage depending on the difference in oxygen concentration between the exhaust gas and the free air. These sensors generally sit at 0.45 V when the fuel mixture is stoichiometric, but rapidly change to 0.1 V in a lean condition and 0.9 V in a rich condition. The response is highly non-linear, and changes greatly with respect to temperature, and thus is only good for telling the ECU if it’s rich or lean, but not by how much. ECUs with narrowband sensors tend to hunt a lot when running in closed loop O2 control – you’ll see an engine at idle hunt either side of the magical 14.7 stoichiometric air fuel ratio, never able to quite dial in on the correct number.

As I intend to switch to an aftermarket ECU in the future, I’ll need to tune the car. This involves making sure the air/fuel ratios (AFRs) are correct, and for that I need to be able to properly measure them. Just knowing whether you’re rich or lean isn’t enough, as often it’s desirable to run the engine intentionally rich or lean at certain engine loads. To get a true AFR reading requires fitting a wideband oxygen sensor. These are a little more complicated.

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Get Your Eclipse Glasses Emblazoned with Hackaday

We’re getting ready to stare at the Sun for a few hours when a total solar eclipse is visible across the United States on August 21st. You could protect your eyes with some welding goggles, but why not wear a pair of Hackaday eclipse glasses instead?

UPDATE: And They’re Gone. We had a huge response to this with over 200 event pages made in just a few hours (and more coming since then; thank you, you’re awesome!). We had 500 glasses to give away and are sending them out in envelopes of 4. We would still love it if you made an event page but unfortunately we’ve run out of glasses to send out.

Let us know where you’ll be watching the eclipse and we’ll mail you some custom-printed Hackaday eclipse glasses (sorry, they’re all gone).  Head over to the Eclipse Meetups page, click the “Host a Meetup” button and tell us where you’ll be. We’ll add you to the map and contact you for the shipping address and the number of glasses you’ll need.

Whether you want others to join you or not is your choice, but we want to see a map full of pins where the Hackaday community is taking part in this momentous event.

As you can see, there are already a number of meetups watch the partial eclipse and that’s fine with us. No matter where you are, if you can see the eclipse we’re ready to send you some glasses. Hurry up though, they need to arrive before Monday!

Smart Speed Bumps Slow Only Speeding Cars

Like it or not speed bumps are an essential part of our road infrastructure especially in built-up places like near schools [Business Insider UK] reports non-Newtonian liquid filled speed bumps are being tested in Spain, Israel and Germany.

Traditional speed bumps do have their drawbacks; damage to the underside of low vehicles is common. While they should be uniform in dimensions, in practice they can vary significantly, making driving over unfamiliar bumps a bit unpredictable. This is all set to change with non-Newtonian bumps which are soft to drive over at slow speeds but for speeding drivers they harden up and act more like traditional bumps. This gives drivers following the letter of the law a better driving experience whilst still deterring speeding drivers..

Non-Newtonian materials are nothing new but we think this is a great way of purposing these type of materials. Roads are getting smart whether you like it or not. It’s time to embrace technology and improve our commutes.  Continue reading “Smart Speed Bumps Slow Only Speeding Cars”

Hands On With The SHACamp 2017 Badge

The badge has become one of the defining features of a modern hacker camp, a wearable electronic device that serves as both event computer and platform for some mild software and hardware hacking. Some events have had astoundingly sophisticated badges while others are more simple affairs, and the phenomenon has even spawned an ecosystem of unofficial badges which have nothing to do with the event in question.

The SHACamp 2017 badge is the latest to come the way of a Hackaday writer, and certainly contains enough to be taken as representative of the state of hacker camp badges in 2017. It doesn’t have a star turn like CCCCamp 2015’s software defined radio, instead it’s an extremely handy little computer in its own right.

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