Spain’s First Open Source Satellite

August 15, 2019 by 27 Comments

[Fossa Systems], a non-profit youth association based out of Madrid, is developing an open-source satellite set to launch in October 2019. The FossaSat-1 is sized at 5x5x5 cm, weighs 250g, and will provide free IoT connectivity by communicating LoRa RTTY signals through low-power RF-based LoRa modules. The satellite is powered by 28% efficient gallium arsenide TrisolX triple junction solar cells.

The satellite’s development and launch cost under EUR 30000, which is pretty remarkable for a cubesat — or a picosatellite, as the project is being dubbed. It has been working in the UHF Amateur Satellite band (435-438 MHz) and recently received an IARU frequency spectrum allocation for LoRa of 125kHz.

The satellite’s specs are almost as remarkable as the acronyms used to describe them. The design includes an onboard computer (OBC) based on an ATmega328P-AU microcontroller, an SX1278 transceiver for telecommunications, and an electric power system (EPS) based on three SPV1040 MPPT chips and the TC1262 LDO. The satellite also uses a TMP100 temperature sensor, an INA226 current and voltage sensor, a MAX6369 watchdog for single-event upset (SEU) protection, a TPS2553 for single-event latch-up (SEL) protection and various MOSFETs for the deployment of solar panels and antennas.

Up until this point the group has been tracking adoption of LoRa through the use of weather balloons. The cubesat project plans to test the new LoRa spread spectrum modulation using less than $5 worth of receivers. Ultimately with the goal of democratizing telecommunications worldwide.

The satellite is being built in a cleanroom at Rey Juan Carlos University and has undergone thermovacuum and vibration testing at the facility. The group has since developed an educational satellite development kit, which offers three main 40×40 mm boards that allow the addition of modifications. As their mission states, the group is looking to develop an open source project, so the code for the satellite is freely available on their GitHub.

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Fail Of The Week: Supercapacitor Spot Welder

August 15, 2019 by 33 Comments

[Julian] needed to weld a bit of nickel to some steel and decided to use a spot welding technique. Of course he didn’t have a spot welder sitting around. Since these are fairly simple machines so [Julian] set out to build a spot welder using a charged supercapacitor. The fundamentals all seem to be there — the supercap is a 100 Farad unit and with a charge of 2.6V, that works out to over 300 joules — yet it simply doesn’t work.

The problem is in how the discharge energy is being directed. Just using the capacitor would cause the charge to flow out as a spark when you got near the point to discharge. To combat this, [Julian] put a microswitch between the capacitor and the copper point he expected to use as the welding tip. The microswitch, of course, is probably not the best for carrying a large surge of current, so we suspect that may be part of why he didn’t get great results.

The other thing we noticed is that he used a single point and used the workpiece as a ground return. Most spot welders use two points near each other or on each side of the workpiece. The current from the capacitor is probably just absorbed by the relatively large piece of metal.

The second video below from [American Tech] shows a 500F capacitor doing spot welding with little more than two wires and it seems to work. Hackaday’s own [Sean Boyce] even made one out of some whopping 3000F caps. It did work, although he’s been pursuing improvements.

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Uncovering The Echo Dot’s Hidden USB Port

August 15, 2019 by 62 Comments

If you upgraded to Amazon’s latest Echo Dot, you might have been surprised to find that the diminutive voice assistant had shed its USB port. Earlier models of the Dot used a garden variety micro USB port for power, which hackers eventually figured out also provided a helpful way to snoop around inside the device’s firmware. The fact that the USB port was deleted on the latest Echo Dot in favor of a simple barrel connector for power was seen by some as a sign that Amazon was trying to keep curious owners out of their hardware.

But as [Brian Dorey] shows, all they did was put a bump in the road. While they removed the external USB connector, the traces for it are still on the board waiting to be accessed. Even better, it turns out the USB data lines are connected to the test points located on the bottom of the Dot. All you need is a simple breakout that will connect through the existing opening in the device’s case, and you’ve got your USB port back.

So what can you do with USB on the Echo Dot? Well, not much right now. [Brian] found that the Dot shows up as a Mediatek device under Linux using lsusb, and fastboot can see it and even confirms the presence of a locked bootloader. It’s going to take some work from the community to see how deep this particular rabbit hole goes.

Even if you’re not interested in restoring its USB port, [Brian] has uncovered a wealth of fascinating hardware information about the Echo Dot during his deep-dive. He’s mapped out many of the test points located throughout the device’s PCBs, and found a few interesting points that might be worth further investigation. For example, he found that driving one of the pins high would trigger the Dot to mute its microphones; which could be useful for anyone looking to cover Alexa’s ears.

[Brian] first cracked open the Echo Dot last month, after scoring one for cheap during Amazon’s Prime Day sale. It looks like he’s making fairly rapid progress on unraveling the mysteries of this popular gadget, and we’re very interested in seeing where this research takes us.

Safety Systems For Stopping An Uncontrolled Drone Crash

August 15, 2019 by 33 Comments

We spend a lot of time here at Hackaday talking about drone incidents and today we’re looking into the hazard of operating in areas where people are present. Accidents happen, and a whether it’s a catastrophic failure or just a dead battery pack, the chance of a multi-rotor aircraft crashing down onto people below is a real and persistent hazard. For amateur fliers, operating over crowds of people is simply banned, but there are cases where professionally-piloted dones are flying near crowds of people and other safety measures need to be considered.

We saw a skier narrowly missed by a falling camera drone in 2015, and a couple weeks back there was news of a postal drone trial in Switzerland being halted after a parachute system failed. When a multirotor somehow fails while in flight it represents a multi-kilogram flying weapon widow-maker equipped with spinning blades, how does it make it to the ground in as safe a manner as possible? Does it fall in uncontrolled flight, or does it activate a failsafe technology and retain some form of control as it descends?

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DIY PC Test Bench Puts Hardware Troubleshooting Out In The Open

August 15, 2019 by 20 Comments

If you’ve built a few PCs, you know how frustrating troubleshooting can be. Finding a faulty component inside the cramped confines of a case can be painful — whether its literal when sharp edges draw blood, or just figurative when you have to open that cramped case multiple times to make adjustments.

[Colonel Camp] decided to make life a bit easier by building this PC test bench which makes component troubleshooting much easier and can be built with old parts you probably have lying around. [Camp] was inspired by an old Linus PC Tech Tips video on the same topic. The key to the build is an old PC case. These cases are often riveted together, s a drill makes quick work of disassembling the chassis to easily get to all of the components. The motherboard pan and rear panel/card cage become the top shelf of the test bench, while the outer shell of the case becomes the base and a storage area. Two pieces of lumber support the upper shelf. The build was primed and painted with several coats of grey.

[Camp] built up his testbench with a modest motherboard, cooler and a 970 video card. He loaded up Manjaro Linux to verify everything worked. The basic hardware has already been replaced with a new system including a ridiculously huge cooler. But that’s all in a day’s work for a test bench PC.

We’ve seen some wild workbenches over the years, and this one fits right in for all your PC projects. Check out the video after the break!

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Millenium Falcon HID: Get Unity To Talk To Teensy

August 15, 2019 by 11 Comments

Here’s one that proves a hardware project can go beyond blinking LEDs and dumping massive chunks of data onto a serial console. Those practices are fine for some, but [dimtass] has found a more elegant hack for a more civilized age. His 3D Millennium Falcon model gets orientation data from his IMU as an an HID device.

The hardware involved is an MPU6050 6-axis sensor that is interfaced with a Teensy 3.2 board. [dimtass] documents his approach to calibrating the IMU going a bit further by using a Python script to generate offsets. We’ve advocated using Jupyter notebooks in the past and this is a good example of Jupyter plotting the data and visualizing the effect of the offsets in a second pass.

When in action, the Teensy reads IMU data and sends it over a USB RAW HID interface. For the uninitiated, HID transfers are more reliable than USB CDC transfers (virtual serial port) because they use smaller data chunks per event/transaction and usually don’t require special drivers.  On the computer side, [dimtass] has written a small application that gets the IMU values over the RAW HID and then provides it to the visualization application.

A 3D Millennium Falcon model is rendered in Unity, the popular open source game development engine. Even though Unity has an API, this particular approach is more OS specific using a shared-memory technique. The HID application writes to a file (/tmp/hid-shared-buffer) which is then read by Unity to make orientation changes to the rendered model.

[dimtass] provides lots of details on the tools used to bring his project to life and it can be a great starting point for more projects that need interfacing sensors with a visualization system. We have seen ways to turn a person’s head into a joystick and if you need a deeper dive into Unity, look no further.

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Overclocking In An SNES Emulator

August 14, 2019 by 12 Comments

The bsnes emulator has a new overclocking mode to eliminate slowdowns in SNES games while keeping the gameplay speed accurate. We’re emulating old SNES hardware on modern machines that are vastly more powerful. Eliminating slowdowns should be trivial, right? For an emulator such as bsnes, which is written to achieve essentially pixel-perfect accuracy when emulating, the problem is decidedly non-trivial. Stick around to learn why.

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