A STM32F4 Based Arduino In The Feather Form Factor

[minh7a6] loves the Adafruit Feather, but sees some room for improvement.

First is the matter of 5V tolerance. While just about everything is available in a 3.3v range these days, sometimes it’s just nice not to have to care. The main controller on the Feather is plenty powerful, but its intolerant pins just wouldn’t do so it was swapped for a chip from the ever popular STM32F4 line.

Then he wanted better energy efficiency when running from battery. In order to achieve this he switched from a linear regulator to a buck-boost converter. He also felt that the need for a separate SWD adapter for debugging seemed unnecessary, so he built a Black Magic Probe right in.

He’s just now finishing up the Arduino IDE support for the board, which is pretty cool. There’s no intention to produce this souped up Feather, but all the files are available for anyone interested.

Let A CPR Robot Save The Day

Four highschool students in Lyon France are building a CPR robot, with the aim of removing the endurance problem faced by those delivering this form of essential first aid.

By every after action report, CPR is an emotionally and physically exhausting way to save a life. When someone’s heart stops beating their breathing stops too. After that there’s a very small window in which to keep just enough oxygen in the blood to prevent brain damage and organ failure. A person has to precisely position their hands and press, repeatedly, with enough force to break someone’s sternum in order to keep their heart pumping; sometimes for over fifteen minutes waiting for rescue to arrive. On top of that, depending on which school of thought they learned the technique, they may be required to also force air into the patients lungs.

While this pushes the boundary of human endurance, a robot would not have the same issue. In fact, many of the existing problems are solved. CPAP Machines can force air into lungs all day long. A motor and a mechanism could position and provide the mechanical pumping motion to keep the blood flowing. Sensors could tell when the heart takes back over. The machine is currently a proof-of-concept built from plywood, and off-the-shelf parts. Yet it can maintain the 30 compression – 2 breath cycle indefinitely on a CPR Dummy.

It’s an interesting idea; while defibrillators do exist, they don’t always get the heart going in time. We wonder if someone more medically inclined can weigh in on this interesting idea.

Landbeest, A Single Servo Walking Robot

Walking robots have a rich history both on and off the storied pages of Hackaday, but if you will pardon the expression, theirs is not a field that’s standing still. It’s always pleasing to see new approaches to old problems, and the Landbeest built by [Dejan Ristic] is a great example.

It’s a four-legged walker with a gait dictated by a cam-and-follower mechanism that allows it to perform the full range of leg movement with only one motor. Each cam can control more than one leg in synchronisation, and in his most recent prototype, there are two such mechanisms that work on opposite corners of a four-legged machine. The legs are arranged in such a way that the two corner-to-corner pairs pivot at their centres in a similar manner to a pair of scissors; allowing a servo to steer the robot as it walks.

The result certainly isn’t as graceful as [Theo Janssen]’s Strandbeest, from which it evidently takes inspiration for its name, but it’s no less capable for it. After the break you can see a video he’s posted which clearly illustrates its operation and demonstrates its ability to traverse obstacles.

The only thing that’s missing are the files and software should you wish to create your own. He’s unapologetic about this, pointing out that he’d prefer to wait until he is satisfied with it before letting it go. Since he’s put a lot of work in so far and shows no sign of stopping, we’re sure he’ll reach that point soon enough.

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Iron Man Puts Yet Another Hacker Up In Arms

When Iron Man movie came out, we’d bet there wasn’t a single hacker that left the theater without daydreaming about having a few robotic lab assistants of their own. But unlike most of them, [Tony-Lin] decided to turn his celluloid dreams into a reality and started work on his robotic arm, Abot.

Abot is built from a combination of 5 mm nylon panels and 3D printed parts. One thing we found particularly interesting about this build is that the motor reductions for the joints are done using stages of pulleys and GT2 belting rather than planetary gear boxes or cycloidal drives. This produces a lightweight and affordable build.

He also designed his own driver boards for each motor using the STM32. They communicate with a CAN bus which uses USB connectors, an interesting choice. Just make sure not to try and charge your phone with it.

We have to admit to a little jealousy that [Tony] is moved himself a bit closer to being Tony Stark than the rest of us are likely to get. We’ll just have to live vicariously through the documentation of his project.

InstaBeat Started Out Of Spite

[Tom] teaches electronics with this small programmable MP3 player, but it didn’t get its start as a teaching tool.

As all parents are sometimes required to do, [Tom] was acting as chauffeur for his daughter and his friends. When he played the Beatles one of his passengers informed him that she was completely devoid of taste and didn’t like them at all. So he decided what the world needed was a Beatles appliance. This way all the ignorant plebs could educate themselves at the push of a button.

The machine is based around some SEED studio parts and a simple PCB. It was able to hold all 12 original albums and even announced their titles in a generated voice. Since the kit is easy to put together it was quickly re-purposed as a teaching aid. They get to learn the laser cutter and do some through-hole soldering.

He has plans to turn it into a more formal how-to workshop that anyone can duplicate.He’d also like to make a small software suite for playing with text-to-speech and hacking the speaker into other roles such as a multi meter.

If You Need A Measurement Tool Just Build A Measurement Tool

[Darlan Johnson] was working on a wearable project and needed a way to measure the change in voltage and current over time. 

Most measurement tools are designed to take snapshots of a system’s state in a very small window of time, but there are few common ones designed to observe and log longer periods. It’s an interesting point, for example, many power supply related failures such as resets occur sporadically. Longer timescale measuring devices could pick these up.

[Darlan] had a ton of Feathers and shields lying around, and combined them into the needed instrument. An INA219 current sensor records the measurements. They are then displayed on a TFT and logged to an SD card. Everything is bundled into a neat 3D printed case along with a battery for wireless operation. A set of barrel connectors provide the breakout to split the wires for the current measurement.

It’s a neatly done hack and we can see it as a nice addition to any hacker’s measurement drawer.

Feel The Virtual Road With Force Feedback

When you’re driving your virtual supercar around the Italian countryside the last thing you want is an inauthentic steering wheel feel, that’s where Open FFBoard comes in. Racing game enthusiasts will go to impossible and sometimes incredibly expensive lengths to build extravagant simulators. [Yannick] feels many of these products are just a little too pricey without much need.

Right now his board is still in a process of iteration, though it can integrate with Assetto Corsa already. You can see in the demo video after the break that it responds quite realistically to the video game state, however problems keep cropping up in search of solutions. Motor drivers burn out and power resistors are added: that energy has to go somewhere. Next up will be switching to the increasingly popular Trinamic drivers. Either way we can’t wait to see the next revision and to get another amazing simulator build sent in to us, maybe centered around the Open FFBoard.

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