Launch And Track Your Model Rockets Via Smartphone

Building and flying model rockets is great fun. Eventually, though, the thrill of the fire and smoke subsides, and you want to know more about what it’s doing in the air. With a thirst for knowledge, [archy587] started building a project to monitor the vital stats of rockets in flight. 

The project mounts an M0 Feather microcontroller board into the rocket, along with a 900 MHz LoRa transmitter and a GPS module. This allows the rocket’s journey to be measured and logged, and is particularly useful for when a craft floats off downrange during parachute recovery. There’s also a relay module onboard, which dumps power from a dedicated separate battery into the rocket motor igniter. This allows the rocket to be fired wirelessly.

On the ground, the setup uses an ESP32 fitted with another LoRa module to receive signals from the rocket. It’s designed to hook up to an Android smartphone over its USB-C port. This allows data received from the rocket to be displayed in an Android app, including the rocket’s GPS location overlaid on Google Maps.

Being able to remotely ignite your rockets and track their progress brings some high-tech cool to the launch pad. You’ll be upgrading your rockets with micro flight controllers and vectored thrust in no time. Just be sure whatever tech you’re using is compliant with the rules for model rocketry in your local area.

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Movie Prop Electronics Hack Chat Takes Us Behind The Scenes

It’s no surprise that the hacking and making community has traditionally had something of a love affair with movie props, especially those of the science fiction variety. Over the years we’ve seen folks put untold hours into incredible recreations of their favorite pieces of fictional gear — and by the time this post goes out, our 2022 Sci-Fi Contest will be entering into the final stretch. So it’s a safe bet that if you make your living by creating the electronics behind all that Hollywood movie magic, you’ll find ours to be an especially welcoming community.

We were fortunate enough to see this in action this week when Ben Eadie stopped by to host the Hack Chat. It’s no exaggeration to say that he’s been living out what most of us would consider a dream, having worked on films from iconic franchises such as Star Trek and Predator. But perhaps his most enviable credit is that of propmaster for 2021’s Ghostbusters: Afterlife, where he got the chance to work on the proton packs and ghost traps; arguably some of the most well-known props in the history of cinema.

Not bad for a guy who only recently got in the game. Ben spent 20 years working as an aerounatical engineer until a friend from his local maker space mentioned they were working on a film and could use a hand. Suddenly he found himself behind the scenes of Star Trek: Beyond in 2015, helping to design and fabricate one of the largest rotating sets ever made. He figures he must have done something right, because Hollywood has been calling ever since.

This anecdote about his first time working on a feature film helped answer what many wanted to know early on in the Chat, which was how one manages to get into the prop and special effects industry. Ben once again confirmed a truth well known to this community: that what you’re capable of is far more important than where you went to school and what you studied. There’s not a lot of formal education out there that can train you to make the impossible possible, and Ben says the majority of his day-to-day knowledge came from a lifetime of fiddling around with electronics. In fact, he attributes much of his professional success with hanging out in maker spaces, reading Hackaday, and watching YouTube. If that’s the recipe, then we should all be in pretty good shape.

Over the last few years, Ben has been trying to pay that forward by documenting some of the tricks of the trade on his own YouTube channel. In a particularly interesting piece of marketing on Sony’s part, some of Ben’s videos have even been featured on the official Ghostbusters YouTube channel as part of a “Maker Monday” series. In fact, we first got in contact with Ben when he left a comment on our coverage of his “PKE  Meter” prop build. This is the kind of advertisement we can get behind, and wish more companies would embrace the hacker and maker culture with this kind of interactive content. Ben says the best way to make initiatives like this more popular is to consume it — if Sony sees people watching and sharing this kind of content, hopefully more will follow.

Of course, it wouldn’t be a Hack Chat unless some arcane compartmentalized technical knowledge was dished out. In this case, several of the questions were about the unique challenges posed by operating custom electronics on a movie set. For example, Ben says he always uses addressable LEDs controlled by the APA102 chip as it offers an external clock pin that he can feed with a different frequency to avoid on-screen flickering. The radio spectrum also tends to be pretty noisy on set, so if at all possible, you want to make sure your gear has a wired connection. Otherwise, you’ll need to get intimately acquainted with what other RF signals are being used on set so as not to interfere with the production.

Ben’s creations include the Remote Trap Vehicle (RTV) from Ghostbusters: Afterlife.

But while some of the challenges he has to deal with might seem pretty foreign to us, the technology itself is in some cases more familiar than you might think. It turns out there’s plenty of Sparkfun and Adafruit gear behind the scenes, with Ben specifically mentioning the Feather nRF52 as one of his go-to microcontrollers. Sometimes the graybeards on set grumble about his “consumer grade” tech, but when his gear is up and running in half the time, it’s usually he who gets the last laugh.

Towards the end of the Chat, Ben says the most important thing he’s learned over the years is to always have backups. His motto is “One is None”, and if he can help it, he usually builds four of everything: that gives him two to learn from, and a pair to actually use for whatever the project is. Even if our own projects don’t quite rise to the level of a key prop from a summer blockbuster, there’s no certainly no harm in being prepared.

We want to thank Ben Eadie for taking the time to talk with the community and sharing some of his fascinating stories and tips with us. At the risk of sounding a bit sappy, stories like his are what motivates us here at Hackaday. If we can provide even a small part of the what it takes to help people like Ben achieve their goals, that’s reason enough for us to keep the lights on.


The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.

Palm portable keyboard gone Bluettoh

Palm Portable Keyboard Goes Wireless

Long ago when digital portables where in their infancy, people were already loath to type on tiny keyboards, stylus or not. So Palm made a sweet little portable keyboard that would fold up and fit in your cargo pocket. And what do we have now for luxury typing on the go? Rubber roll-up jelly keebs? That’s a hard no from this scribe.

But why mess with the success of the the Palm Portable Keyboard? It just needs to be updated for our times, and that’s exactly what [Xinming Chen] did with their PPK Bluetooth adapter.

Inspired by the work of [cy384] to make a USB adapter as well as [Christian]’s efforts with the ESP32, [Xinming Chen] points out that this version is more power efficient, easier to program, and has a built-in Li-Po charging circuit. It also uses the hardware serial port instead of the software serial, which saves brainpower.

There’s really not much to this build, which relies on the Adafruit Feather nRF52840 and will readily work with Palm III and Palm V keyboards. Since the PPK is RS-232 and needs to be TTL, this circuit also needs a voltage level inverter which can be made with a small handful of components. We love that there’s a tiny hidden switch that engages the battery when the adapter clicks on to the connector.

The schematic, code, and STL files are all there in the repository, so go pick up one of these foldy keebs for cheap on the electronic bay while they’re still around. Watch the demo video unfold after the break.

Want an all-in-one solution for typing on the go? Check out the history of tiny computers.

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Guitar Pickguard Adds MIDI Capabilities

For a standard that has been in use since the 1980s, MIDI is still one of the most dominant forces on the musical scene even today. It’s fast, flexible, and offers a standard recognized industry-wide over many different types of electronic instruments. Even things which aren’t instruments can be turned into musical devices like the infamous banana keyboard via the magic of MIDI, and it also allows augmentation of standard instruments with other capabilities like this guitar with a MIDI interface built into the pick guard.

[Ezra] is the creator of this unique musical instrument which adds quite a few capabilities to his guitar. The setup is fairly straightforward: twelve wires run to the pick guard which are set up as capacitive sensors and correspond with a note on the chromatic scale. Instead of using touchpads, using wires allows him to bend away the “notes” that he doesn’t need for any particular piece of music. The wires are tied back to an Adafruit Feather 32u4 microcontroller behind the neck of the guitar which also has a few selectors for changing the way that the device creates tones. He can set the interface to emit single notes or continuously play notes, change the style, can change their octave, and plenty of other features as well.

One of the goals of this project was to increase a guitar player’s versatility when doing live performances, and we would have to agree that this gives a musician a much wider range of abilities without otherwise needing a lot of complex or expensive equipment on stage. We’ve seen a few other MIDI-based builds focused on live performances lately, too, like this one which allows a band to stay in sync with each other.

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Portrait Of A Digital Weapon

Over the years, artists have been creating art depicting weapons of mass destruction, war and human conflict. But the weapons of war, and the theatres of operation are changing in the 21st century. The outcome of many future conflicts will surely depend on digital warriors, huddled over their computer screens, punching on their keyboards and maneuvering joysticks, or using devious methods to infect computers to disable or destroy infrastructure. How does an artist give physical form to an unseen, virtual digital weapon? That is the question which inspired [Mac Pierce] to create his latest Portrait of a Digital Weapon.

[Mac]’s art piece is a physical depiction of a virtual digital weapon, a nation-state cyber attack. When activated, this piece displays the full code of the Stuxnet virus, a worm that partially disabled Iran’s nuclear fuel production facility at Natanz around 2008. Continue reading “Portrait Of A Digital Weapon”

Giant DIY Mouse Sets The Ball Free

Make the move to a split keyboard and the first thing you’ll notice is that you have all this real estate between the two halves. (Well, as long as you’re doing it right). This is the perfect place to keep your cat, your coffee cup, or in [Jacek]’s case, your fantastic DIY trackball mouse.

Don’t be fooled by the orange plastic base — all the electronics are rolled up inside that big sexy ball, which [Jacek] printed in two halves and glued together. Inside the ball there’s an Adafruit Feather nRF52840 Sense, which has an onboard accelerometer, gyroscope, and magnetometer. As you’ll see in the video after the break, the Feather takes readings from these and applies a sensor-fusing algorithm to determine the ball’s orientation in 3D space before sending its position to the computer. To send the click events, [Jacek] baked some mouse buttons into the keyboard’s firmware. Among the other Feather sensors is a PDM MEMS microphone, so detecting taps on the ball and translating them to clicks is not out of the question for a future version.

Here comes the really clever part: there are two reed switches inside the ball. One is used as a power switch, and the other is for setting the ‘up’ direction of the trackball. The ball charges wirelessly in a 3D printed base, which also has a small neodymium magnet for activating the reed switches. Check out the demo after the break, which shows [Jacek] putting the trackball through its paces on a mouse accuracy testing program.

If you prefer your DIY trackballs to be more standard looking, click on over to the Ploopy project.

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Learning To Speak Peloton

Recently [Imran Haque]’s family bought the quite popular Peloton bike. After his initial skepticism melted to a quiet enthusiasm, [Imran] felt his hacker curiosity begin to probe the head unit on the bike. Which despite being a lightly skinned android tablet, has a reputation for being rather locked down. The Peloton bike will happily collect data such as heart rate from other devices but is rather reticent to broadcast any data it generates such as cadence and power. [Imran] set out to decode and liberate the Peleton’s data by creating a device he has dubbed PeloMon. He credits the inspiration for his journey to another hacker who connected a Raspberry Pi to their bricked exercise bike.

As a first step, [Imran] step began with decoding the TRRS connector that connects the bike to the head unit. With the help of a multi-meter and a logic analyzer, two 19200bps 8N1 RS-232 channels (TX and RX) were identified. Once the basic transport layer was established, he next set to work decoding the packets. By plotting the bytes in the packets and applying deductive reasoning, a rough spec was defined. The head unit requested updates every 100ms and the bike responded with cadence, power, and resistance data depending on the request type (the head unit did a round-robin through the three data types).

Once the protocol was decoded, the next step for [Imran] was to code up an emulator. It seems a strange decision to write an emulator for a device with a simple protocol, but the reasoning is quite sound. It avoids a 20-minute bike ride every time a code change needs to be tested. [Imran] wrote both an event-driven and a timing-accurate emulator. The former runs on the same board as the PeloMon and the latter runs on a separate board (an Arduino).

The hardware chosen for the PeloMon was an Adafruit Feather 32u4 Bluefruit LE. It was chosen for supporting Bluetooth LE as well as having onboard EEPROM. A level shifter allows the microcontroller to talk directly to the RS-323 on the bike. After a few pull requests to the Adafruit Bluetooth libraries and a fair bit of head-banging, [Imran] has code that advertises two Bluetooth services, one for speed and another for power. A Bluetooth serial console is also included for debugging without having to pull the circuit out.

The code, schematics, emulators, and research notes are all available on GitHub.