Espressif Releases ESP8266-Killer!

June 21, 2016 by Elliot Williams 135 Comments

It’s no secret that we love the ESP8266 chip, and the community of hackers that have contributed to making it useful. We often joke about this or that new WiFi-enabler being an ESP8266 killer, but so far none have stepped up. Here we go again!

Espressif has released a chip that’s going to be an ESP8266 killer, and no, it’s not the ESP32. The ESP8285 went into mass production in March, and should start to appear in the usual outlets fairly soon.

What makes it an ESP8266 killer? It’s an ESP8266, but with the flash memory onboard. Nothing more, but also nothing less. What does this mean? Tiny, tiny designs are possible. And, if the street price ends up being right, there’s no reason you wouldn’t opt for built-in flash. (Unless you were planning on doing some ROM hacking.)

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Very Clever 555 Bassline Synth/Sequencer

June 18, 2016 by Elliot Williams 13 Comments

If we had a dime for every 555-based noisemaker circuit we see… But this one’s got a twist.

[Tristan] does two things that elevate his sawtooth-wave noisemaker above the norm. First, he gets a clean sawtooth wave out of it so that it sounds about right. Then he manages to make it more or less playable. It’s a refined version of a classic hack.

The first trick is a matter of putting a constant current supply upstream of the timing capacitor. The usual 555-timer circuit just charges the capacitor up from the power rails through a resistor. This is fine if all you care about is timing. But because the current is proportional to the constantly dropping voltage difference, the voltage on the capacitor is an exponential function over time.

A simple transistor current source linearizes the waveform in no time. Raw sawtooth waves are “rich in harmonics” which is synth-geek code for “a bit grating”, but it will surely do well with a little filtering. The Javascript suggests that he’s already thinking in that direction, but we’re going to need video proof!

The second cool trick up [Tristan]’s sleeve is the light-dependent resistor (LDR) that determines the pitch. Yeah, we’ve all made those before — the light-dependent “Theremin”. But [Tristan] took the extra step and wrote up a Javascript application that makes his monitor brighter and darker, enabling him to get musical pitches out of the gizmo.

We’ve always wanted to implement LED-to-LDR control while writing the Logic Noise series, but never found a reliable way to make it work. It’s cool to see [Tristan]’s efforts. Maybe we’ll pull a 555 out of the junk box in his honor.

Solvespace: A Parametric CAD Tool

June 18, 2016 by Elliot Williams 31 Comments

3D printing seems like it takes forever when you’re waiting for a part to come out. But if you’re like us, the real time spent in making something new is in modelling and refining the piece. There are tons of CAD programs out there, and finding one that meets your needs is part functionality and part personal preference. Reader [Leibowitz] pointed us to Solvespace, and it looks like it fills the gap between something like OpenSCAD and something more feature-full (and complicated) like FreeCAD.

We’re wondering why we hadn’t heard of Solvespace before. It looks great. It has a lot of what we like about OpenSCAD — the ability to quickly and easily specify two 5 mm holes exactly 21 mm from each other, center-to-center and then change that distance easily. But it also has other features like constraint solvers for mechanisms and linkages. It looks like a great way to design your next Strandbeest. The tutorials seem like a good way to get started quickly.

As we said above, choosing a 3D modeller is partly based on your requirements, but also partly on your feelings. If you’re feeling limited by OpenSCAD, there’s also ImplicitCAD. Or try out Autodesk’s free (but not open) Fusion 360. And now there’s Solvespace. It’s great to have options.

Easy DIY Telemetry Goes The Distance

June 18, 2016 by Elliot Williams 11 Comments

[Paweł Spychalski] wrote in to tell us about some experiments he’s been doing, using cheap 433 MHz HC-12 radio units as a telemetry radio for his quadcopter.

In this blog post, he goes over the simple AT command set, and some of the limitations of the HC-12 part. Then he takes it out for a spin on his quadcopter, and finds out that his setup is good for 450 meters in an open field. Finally, he ties the radio into his quad’s telemetry system and tethers the other end to his cellphone through a Bluetooth unit for a sweet end-to-end system that only set him back around $20 and works as far out as 700 meters.

The secrets to [Paweł]’s success seem to be some hand-made antennas and keeping the baud rate down to a reasonable 9600 baud. We wonder if there’s room (or reason?) for improvement using a directional antenna on the ground. What say you, Hackaday Antenna Jockeys?

Also check out this very similar build where an ESP8266 replaces the Bluetooth module. And stashes it all inside a nice wooden box! Nice work all around.

Marvelous MIDI Button Box

June 18, 2016 by Elliot Williams 1 Comment

Most DJ tools are just ripe for DIY rework. Everything at least speaks MIDI, and the firmware side of the equation that makes a physical interface for your laptop can be downloaded and flashed with minimal effort. And this means that there’s no time better than the present to wire up a ton of buttons to a Teensy and call it a controller.

[UmamiFish]’s build goes the extra mile, though, with a nice laser-cut box and holes for display LEDs as well as the 22 arcade buttons that are packed tightly into the enclosure. A 74HC595 shift-register IC handles the LEDs, but there’s no getting around a bunch of wiring in a build like this. It pays to be neat, and using ribbon cable helps keep some of the chaos under control.

Browsing around Instructables will turn up myriad similar controllers, should the exact configuration of this one not suit your needs. And if you want something with a little more of the real-disk feel, have a look at this controller that uses hard disk platters, or this log of a timecode-vinyl-to-MIDI build.

Ask Hackaday: Whatever Happened To LED Light Sensors?

June 17, 2016 by Elliot Williams 17 Comments

If you’re a long-time Hackaday reader like we are, you’ll certainly remember a rash of projects from around ten years ago that all (mis-)used an LED as a light sensor. The idea wasn’t new, but somehow it made the rounds and insinuated itself into our collective minds. Around the same time, a cryptographic cipher with an exceptionally small memory footprint was also showing up in hacker projects: TEA (Tiny Encryption Algorithm).

This old project by [Marcin Bojanczyk], [Chris Danis], and [Brian Rogan] combines both the LED-as-light-sensor meme and TEA to make a door-entry keyfob that works over visible light. And they do so using almost nothing — a few LEDs and just over 2Kb of code. It’s pretty sweet.

Which brings us to the question: where are they (LED-sensors and TEA) now?

LED-as-light-sensor was just cool. We certainly loved the idea back in 2006. But [Forrest Mims] had been using the phenomenon for decades back then. It certainly makes sense when you’re trying to squeeze as much as possible out of as little as possible, or when budget is a main concern and you just can’t afford an extra photodiode.

But our own experience with LEDs as light sensors is that the results are extremely variable across different LEDs. Code that works with water-clear red LEDs might not work with the ones that come in red-tinted plastic, for instance. Is that why they went extinct?
Similarly, the TEA family of ciphers showed up in a bunch of projects around this time, from the badge for the HOPE conference in 2010 to a widely used RFM12B radio library. There are a couple of attacks on XXTEA, but they only affect reduced-round versions of the cipher, and rely on a tremendous amount of intercepted data — more than we’d see in a home-automation network over years.

Over the last five years or so, there’s been a lot more Internet of Things, which means using standard Internet-style encryption methods (AES and so on) that are widespread on non-memory-constrained computers. Is that what happened to XXTEA?

Anyway, we got tipped off to a project that combined a few of our favorite (old) ideas in one, so we thought that we’d share. Thanks [Blue Smoke] for the walk down memory lane. Any of you out there keeping the flame(s) alive? Have you used sensing LEDs or XXTEA? Are those projects still going, or do you have any future projects planned with these tricks still up your sleeve? Let us know in the comments below.

Mouse Brains Plus Line Laser Equals Rangefinder

June 17, 2016 by Elliot Williams 14 Comments

[Neumi] wrote in with a sweet robotics hack. It’s a 2D laser distance sensor (YouTube) made with a cheap line laser and an optical mouse’s flow-sensor chip used as a low-resolution camera. In one sense, it’s a standard laser-distance-sensor project. But it is clever for a whole bunch of reasons.

For one, using a mouse sensor as a low-res camera is awesome. It’s designed to read from a standard red LED, so the sensitivity is in just the right ballpark for use with a line laser. It returns a 30×30 pixel greyscale image, which is just about the right amount of data for a low-end microcontroller to handle and keep up with the framerate without resorting to coding tricks.

It’s also no coincidence that these sensors are available with lenses built in, for relatively cheap, on eBay. Apparently the quadcopter gurus use them as if they were mice to visually track their quad’s motion. Hacker spillover!

Detecting the laser line as it reflects off of whatever objects are lying on [Neumi]’s floor could also possibly prove difficult, and might produce false readings in the presence of background illumination. So [Neumi] takes two readings with the camera — one with the laser on and one with it off — and differences them. Done fast enough, this should reduce any non-laser sources down to the sensor’s noise floor. Finally, there’s some thresholding and averaging going on behind the scenes that help make everything work out right. The code is up on GitHub.

Not a bad build for a 2D laser distance system on a budget. If you want to shell out a bit more money, and are into a seriously involved build, this is probably the slickest we’ve seen in a long time. And if you’re thinking that you’ve heard of [Neumi] before, you’re right: we featured this 405mm laser PCB exposer / burner CNC machine just a few months ago.

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