Six Wheels (En)rolling: Mars Rovers Going To School

Few things build excitement like going to space. It captures the imagination of young and old alike. Teachers love to leverage the latest space news to raise interest in their students, and space agencies are happy to provide resources to help. The latest in a long line of educator resources released by NASA is an Open Source Rover designed at Jet Propulsion Laboratory.

JPL is the birthplace of Mars rovers Sojourner, Spirit, Opportunity, and Curiosity. They’ve been researching robotic explorers for decades, so it’s no surprise they have many rovers running around. The open source rover’s direct predecessor is ROV-E, whose construction process closely followed procedures for engineering space flight hardware. This gave a team of early career engineers experience in the process before they built equipment destined for space. In addition to learning various roles within a team, they also learned to work with JPL resources like submitting orders to the machine shop to make ROV-E parts.

Once completed, ROV-E became a fixture at JPL public events and occasionally visits nearby schools as part of educational outreach programs. And inevitably a teacher at the school would ask “The kids love ROV-E! Can we make our own rover?” Since most schools don’t have 5-axis CNC machines or autoclaves to cure carbon fiber composites, the answer used to be “No.”

Until now.

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Open Source Power Converter For The Masses

GaN or Gallium Nitride Transistors have been in the news for their high-frequency and high-efficiency applications. Anyone interested in the Power Converter domain will love this open-source project by Siemens. The offering is called SDI TAPAS and it is a multipurpose GaN FET based board with a TMS320F28x controller onboard.

A quick look at the schematic reveals a lot of stuff going on like current and voltage sense chips along with a neatly designed GaN power stage with by-the-book drivers. There is a plethora of connectors on-board including one for the Raspberry Pi which is an added bonus. The git repository comes with sample code to get you off the ground, with examples running BLDC motors as well as connect it to Siemens MindSphere Cloud Platform.

This platform can be used in a number of functions in addition to motor control, such as battery charging, solar energy harvesting, and wireless charging. There is a presentation(PDF) that is available for download, and if you are looking for use cases there are a number of user build projects on their community site. The schematic and board designs can be used to make your own, or you could ask them for a sample board and they might give away more on their community site.

For those starting out, you might appreciate this tutorial on Buck Converter Efficiency to get a feel for the hardware that goes into such experiments.

Open Source DIY Printers are Alive and Well: What We Saw At ERRF 18

If you follow the desktop 3D printer market, it probably won’t surprise you to hear that nearly every 3D printer on display at the inaugural East Coast RepRap Festival (ERRF) was made in China. Even Printrbot CEO Brook Drumm had to admit that this was the year his company may finally bite the bullet and begin selling a branded and customized printer built overseas.

When you can get a decent (but let’s be clear, not great) 3D printer for $200 USD, it’s no surprise that American and European manufacturers are having a hard time staying competitive. But not everyone is seduced by low-cost printers. They know they could buy a decent printer for a couple hundred bucks, but for them that’s not the point. Some hackers are just as (if not more) interested in designing and building the machines than they are churning out little plastic boats with the finished product.

Luckily for us, these are also the type of folks who document their builds and make all their collected information and design files available for others under an open source license. Such builders exemplify the true spirit of the RepRap movement, and we’re happy to report that in a sea of imported printers, there were several interesting home built open source printers.

Whether you want to build your own copy of one of these machines, or simply get inspired by some of the ideas their creators had, these machines are physical proof that just because you can order a cheap 3D printer on eBay right now doesn’t mean you have to.

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The Smaller, Tinier Arduino Platform

While many of the Arduino platforms are great tools for gaining easy access to microcontrollers, there are a few downsides. Price and availability may be the highest on the list, and for those reasons, some have chosen to deploy their own open-source Arduino-compatible boards.

The latest we’ve seen is the Franzininho, an Arduino Gemma-like board that’s based on the ATtiny85, a capable but tiny microcontroller by Atmel in a compact 8-pin configuration. This board has everything the Gemma has, including a built-in LED and breakout pins. One of the other perks of the Franzininho over the Gemma is that everything is based on through-hole components, making the assembly much easier than the surface mount components of the Gemma.

It’s worth noting that while these boards are open source, the Arduinos are as well. It’s equally possible to build your own 100% identical Arduino almost as easily. If you want more features, you can add your own by starting from one of these platforms and do whatever you want with it, like this semi-educational Atmel breakout board.

Thanks to [Clovis] for the tip!

Reflowduino: Put That Toaster Oven To Good Use

There are few scenes in life more moving than the moment the solder paste melts as the component slides smoothly into place. We’re willing to bet the only reason you don’t have a reflow oven is the cost. Why wouldn’t you want one? Fortunately, the vastly cheaper DIY route has become a whole lot easier since the birth of the Reflowduino – an open source controller for reflow ovens.

This Hackaday Prize entry by [Timothy Woo] provides a super quick way to create your own reflow setup, using any cheap means of heating you have lying around. [Tim] uses a toaster oven he paid $21 for, but anything with a suitable thermal mass will do. The hardware of the Reflowduino is all open source and has been very well documented – both on the main page and over on the project’s GitHub.

The board itself is built around the ATMega32u4 and sports an integrated MAX31855 thermocouple interface (for the all-important PID control), LiPo battery charging, a buzzer for alerting you when input is needed, and Bluetooth. Why Bluetooth? An Android app has been developed for easy control of the Reflowduino, and will even graph the temperature profile.

When it comes to controlling the toaster oven/miscellaneous heat source, a “sidekick” board is available, with a solid state relay hooked up to a mains plug. This makes it a breeze to setup any mains appliance for Arduino control.

We actually covered the Reflowduino last year, but since then [Tim] has also created the Reflowduino32 – a backpack for the DOIT ESP32 dev board. There’s also an Indiegogo campaign now, and some new software as well.

If a toaster oven still doesn’t feel hacky enough for you, we’ve got reflowing with hair straighteners, and even car headlights.

Build Your Own Avionics Suite, If You Dare

If you’re really interested in aircraft and flying, there are many ways to explore that interest. There are models of a wide range of sizes and complexities that are powered and remote-controlled, and even some small lightweight aircraft that can get you airborne yourself for a minimum of expense. If you’re lucky enough to have your own proper airplane, though, and you’re really into open source projects, you can also replace your airplane’s avionics kit with your own open source one.

Avionics are the electronics that control and monitor the aircraft, and they’re a significant part of the aircraft’s ability to fly properly. This avionics package from [j-omega] (who can also be found on will fit onto a small aircraft engine and monitor things like oil temperature, RPM, coolant temperature, and a wide array of other features of the engine. It’s based on an ATmega microcontroller, and has open-source schematics for the entire project and instructions for building it yourself. Right now it doesn’t seem like the firmware is available on the GitHub page yet, but will hopefully be posted soon for anyone who’s interested in an open-source avionics package like this.

The project page does mention that this is experimental as well, so it might not be advised to use in your own personal aircraft without some proper testing first. That being said, if you’ve heard that warning and have decided just to stay on the ground, it’s possible to have a great experience without getting in a real airplane at all.

Pick And Place Machine Is Mirror Image Of 3D Printer

For his Hackaday prize entry, [Daren Schwenke] is creating an open-source pick-and-place head for a 3D printer which, is itself, mostly 3D printable. Some serious elbow grease has gone into the design of this, and it shows.

The really neat part of this project comes in the imaging of the part being placed. The aim is to image the part whilst it’s being moved, using a series of mirrors which swing out beneath the head. A Raspberry Pi camera is used to grab the photos, an LED halo provides consistent lighting, and whilst it looks like OpenPnP may have to be modified slightly to make this work, it will certainly be impressive to see.

Two 9g hobby servos are used: one to swing out the mirrors (taking 0.19 seconds) and one to rotate the part to the correct orientation (geared 2:1 to allow 360 degrees part rotation). Altogether the head weighs 59 grams – lighter than an E3D v6.

In order to bring this project to its current state, [Daren] has had to perform some auxiliary hacks.  The first was an aquarium to vacuum pump conversion – by switching around the valves and performing some other minor mods, [Daren] was able to produce a vacuum of 231mbar. The second was hacking a two-way solenoid valve from a coffee machine into a three-way unit. As [Daren] says, three-way valves are not expensive, but “a part in hand is worth two on Alibaba.”