Return Of The Logic Probe

January 4, 2019 by Al Williams 10 Comments

We live in a day when it is very inexpensive to buy an oscilloscope, especially one with modest performance that hooks to a laptop. However, there was a time when even a surplus scope was out of reach for many people who liked to build things. A common alternative was the logic probe. At the low end, this could be an inverter and an LED, although it was more common to have a little extra circuitry to actually do a comparison to a reference voltage and present some indication of fast pulses — you might not be able to tell the frequency of a clock, but you could tell it wasn’t stuck. Of course, today with a microcontroller you can make a very sophisticated probe with less circuitry than a classic probe. We’ve seen a few takes on this and the latest is the DigiLogicProbe from [TheRadMan].

The probe is just a ATtiny85 board with a handful of components. A resistor and diode help protect the probe and the circuit under test. There are also a few LEDs and a buzzer. The rest of the project is software.

Continue reading “Return Of The Logic Probe” →

Compiling NodeMCU For The ESP32 With Support For Public-Private Key Encryption

January 3, 2019 by Sean Boyce 7 Comments

When I began programming microcontrollers in 2003, I had picked up the Atmel STK-500 and learned assembler for their ATtiny and ATmega lines. At the time I thought it was great – the emulator and development boards were good, and I could add a microcontroller permanently to a project for a dollar. Then the ESP8266 came out.

I was pretty blown away by its features, switched platforms, except for timing-sensitive applications, and it’s been my chip of choice for a few years. A short while ago, a friend gave me an ESP32, the much faster, dual core version of the ESP8266. As I rarely used much of the computing power on the ESP8266, none of the features looked like game changers, and it remained a ‘desk ornament’ for a while.

About seven weeks ago, support for the libSodium Elliptic Curve Cryptography library was added. Cryptography is not the strongest feature of IoT devices, and some of the methods I’ve used on the ESP8266 were less than ideal. Being able to more easily perform public-private key encryption would be enough for me to consider switching hardware for some projects.

However, my preferred automated build tool for NodeMCU wasn’t available on the ESP32 yet. Compiling the firmware was required – this turned out to be a surprisingly user-friendly experience, so I thought I’d share it with you. If I had known it would be so quick, this chip wouldn’t have sat on my desk unused quite so long! Continue reading “Compiling NodeMCU For The ESP32 With Support For Public-Private Key Encryption” →

Picovoice Puts Smarts Offline In 512K Of Memory

January 1, 2019 by Al Williams 36 Comments

We live in the future. You can ask your personal assistant to turn on the lights, plan your commute, or set your thermostat. If they ever give Alexa sudo, she might be able to make a sandwich. However, you almost always see these devices sending data to some remote server in the sky to do the analysis and processing. There are some advantages to that, but it isn’t great for privacy as several recent news stories have pointed out. It also doesn’t work well when the network or those remote servers crash — another recent news story. But what’s the alternative? If Picovoice has its way, you’ll just do all the speech recognition offline.

Have a look at the video below. There’s an ARM board not too different from several we have lying around in the Hackaday bunker. It is listening for a wake-up phrase and processing audio commands. All in about 512K of memory. The libraries are apparently quite portable and the Linux and Raspberry Pi versions are already open source. The company says they will make other platforms available in upcoming releases and claim to support ARM Cortex-M, Cortex-A, Android, Mac, Windows, and WebAssembly.

Continue reading “Picovoice Puts Smarts Offline In 512K Of Memory” →

Pushbutton → Push Notification

December 30, 2018 by Brian McEvoy 21 Comments

How many mundane devices upgrade to IoT because they let you monitor a single data point or a variable? That little nudge over the communication precipice allows you to charge 500% more. Now, if you are as handy as a Hackaday reader, you can throw a lazy afternoon at the problem and get the same effect from a “dumb” appliance. If IoT is as simple as getting a notification when your laundry is dry, or your water is boiling, all you really need is a WiFi device and a push notification, right? Does it need to be more complicated than that? [Gianni] believes it is that simple (machine translation) and has built up an easy-to-implement version on Raspberry Pi, Arduino, and ESP8266.

[Gianni] leverages the aptly named Pushover (a paid app with a 1-week trial period) to convert your bits, bytes, words, or strings to a push notification. This idea is born of the desire for a home security system which doesn’t require constant monitoring but instead alerts you to problems. The minimum requirement you need is for your phone to chime with a notification saying, “Your front window sensor has been tripped.” Now it is time to launch your IP camera app or call someone nearby.

It’s not revolutionary, it may be the “Hello World” of IoT, but that is all some people need. The general idea is the same no matter the framework you want to use. For instance, if you Google Suite account, you can set up a chatroom just for your alert notifications; Google’s quickstart takes about 3 minutes to test it out in Python. The same setup is also available for Slack, and [Tom Nardi] did a guide for doing this with Discord. These tackle the receiving side, but the sending side is really flexible too — that MQTT broker you built could easily be the source of the alerts.

Build a handful of these in a weekend and keep them nearby to step up your next project to IoT status with a couple of solder joints. Maybe it will be a motion sensor for your own security system.

Laser Harp Sounds Real Thanks To Karplus-Strong Wave Equation

December 29, 2018 by Dan Maloney 9 Comments

The harp is an ancient instrument, but in its current form, it seems so unwieldy that it’s a wonder that anyone ever learns to play it. It’s one thing to tote a rented trumpet or clarinet home from school to practice, but a concert harp is a real pain to transport safely. The image below is unrelated to the laser harp project, but proves that portable harping is begging for some good hacks.

Concert grand harps are so big there’s special equipment to move them around. This thing’s called the HarpCaddy

Enter this laser harp, another semester project from [Bruce Land]’s microcontroller course at Cornell. By replacing strings with lasers aimed at phototransistors, [Glenna] and [Alex] were able to create a more manageable instrument that can be played in a similar manner. The “strings” are “plucked” with the fingers, which blocks the laser light and creates the notes.

But these aren’t just any old microcontroller-generated sounds. Rather than simply generating a tone or controlling a synthesizer, the PIC32 uses the Karplus-Strong algorithm to model the vibration of a plucked string. The result is very realistic, with all the harmonics you’d expect to hear from a plucked string. [Alex] does a decent job putting the harp through its paces in the video below, and the write-up is top notch too.

Unique musical instruments like laser harps are far from unknown around these parts. We’ve seen a few that look something like a traditional harp and one that needs laser goggle to play safely, but this one actually looks and sounds like the real thing. Continue reading “Laser Harp Sounds Real Thanks To Karplus-Strong Wave Equation” →

A Different Kind Of Hand Controlled Vehicle

December 28, 2018 by Lewin Day 5 Comments

It’s generally understood that most vehicles that humans interact with on a daily basis are used with some kind of hand controlled interface. However, this build from [Avisha Kumar] and [Leul Tesfaye] showcases a rather different take. A single motion input provides both steer and foward/reverse throttle control.

The hand controller lives on a protoboard for ease of testing.

The project consists of a small car, driven with electric motors at the rear, with a servo-controlled caster at the front for steering. Controlled is provided through PIC32 microcontroller receiving signals via Bluetooth. The car is commanded with a hand controller, quite literally — consisting of an accelerometer measuring pitch and roll position of the user’s hand. By tilting the hand left and right affects steering, while the hand is rotated fore and aft for throttle control. Video after the break.

The project was built for a course at Cornell University, and thus is particularly well documented. It provides a nice example of reading sensor inputs and transmitting/receiving data. The actually microcontroller used is less important than the basic demonstration of “Hello World” with robotics concepts. Keep this one in your back pocket for the next time you want to take a new chip for a spin!

Skeletal Robot Skips The Chassis

December 26, 2018 by Tom Nardi 5 Comments

With the high availability of low-cost modular electronic components, building your own little robot buddy is easier and more affordable than ever. But while the electronics might be dirt cheap thanks to the economies of scale, modular robot chassis can be surprisingly expensive. If you’ve got a 3D printer you can always make a chassis that way, but what if you’re looking for something a bit more artisanal?

For his entry into the Circuit Sculpture Contest, [Robson Couto] has built a simple robot which dumps the traditional chassis for a frame made out of bent and soldered copper wire. Not only does this happen to look really cool in a Steampunk kind of way, it’s also a very cheap way of knocking together a basic bot with just the parts you have on hand. Not exactly a heavy-duty chassis, to be sure, but certainly robust enough to rove around your workbench.

The dual servos constrained within the wire frame have been modified for continuous rotation, which combined with the narrow track should make for a fairly maneuverable little bot. [Robson] equipped his servos with copper wheels built in the same style of the frame, which likely isn’t great for traction but really does help sell the overall look. If you aren’t planning on entering your creation into a contest that focuses on unique construction, we’d suggest some more traditional wheels for best results.

The brains of this bot are provided by an ATmega8 with external 16MHz crystal tacked onto the pins. There’s also a ultrasonic sensor board mounted to the servos which eventually will give this little fellow the ability to avoid obstacles. Of course, it doesn’t take a robotics expert to realize there’s currently no onboard power supply in the design. We’d love to say that he’s planning on using the copper loops of the frame to power the thing via induction, but we imagine [Robson] is still fiddling around with the best way to get juice into his wireframe creation before the Contest deadline.

Speaking of which, there’s still plenty of time to get your own Circuit Sculpture creation submitted. If it’s a functional device that isn’t scared to show off the goods, we’re interested in seeing it. Just document the project on Hackaday.io and submit it to the contest before the January 8th, 2019 deadline.