Author: Brian Benchoff

5250 Articles

New Part Day: The $15 ESP32 With Cellular

July 9, 2019 by 51 Comments

Cruise around AliExpress for long enough and you’ll find some interesting new hardware. The latest is the TTGO T-Call, an ESP32 breakout board that also has a cellular modem. Yes, it’s only a 2G modem, but that still works in a lot of places, and the whole thing is $15.

On board the TTGO T-Cal is the ESP-WROVER-B, the same module you all know and love that features a dual-core ESP running at 240 MHz with 4 MB of Flash and 8 MB of SRAM. Add to this WiFi and Bluetooth, and you have a capable microcontroller platform. Of note is that this board includes a USB-C port, ostensibly wired so that it behaves like a normal USB micro port. That’s neat, 2019 is the year USB C connectors became cheaper than USB micro connectors.

In addition to the ESP32 module, there’s also cellular in the form of a SIM800 module. This module has been around for a while and used in many, many cellular-connected projects and products like the ZeroPhone. This module is only a 2G module, and that’ll be going away shortly (if not already) in built-up areas, but this can serve as a building block for modules that have more Gees than a 2G module. That said, if you’re looking for a WiFi and cellular bridge for fifteen bucks, you could do a lot worse for a lot more money.

Rock, Paper, Neural Net

July 9, 2019 by 6 Comments

You might think the game of Rock Paper Scissors is just the random chance, but that’s not true. There is a strategy for Rock Paper Scissors, multiple ones in fact, and the best human players can consistently beat any Joe Schmoe off the street. But what about computers? [Paul] answered that question with a tiny little keychain dongle that can beat you at Rock Paper Scissors.

This is a neural network, and you need to train a neural network, so where did [Paul] get all that data? roshambo.me offers thousands of paper rock scissor games, and trained the network on more than 85,000 human games, along with about 10,000 simulated games. Rock Paper Scissors isn’t a complicated game at all, and the entire neural network is stored on an ATtiny1614 microcontroller. The calculations are done as floats, even. That’s how non-computationally intensive this project is.

Building a neural network is one thing, but putting it in a handy keychain enclosure is something else. This handsome device fits on a PCB just larger than a 2032 coin cell battery and is enclosed in a 3D printed case. The buttons are 3D printed as well, with some clever application of fiber optic as light pipes for the LEDs. The end result is something that is slightly better than random chance at Rock Paper Scissors and shows off some matrix programming skills. Check out the video below.

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Hackaday Links: July 7, 2019

July 7, 2019 by 7 Comments

Like modular synths? Sure you do, and you need another hole to throw money into! For the last few months, Supplyframe has been hosting synthesizer and electronic music meetups in San Francisco. This week, the HDDG/Piqued meetup will have a great talk with the creator of VCV Rack. VCV Rack is an Open Source, virtual, modular synthesizer — basically a bunch of Eurorack modules inside a computer and it costs a whole lot less. The talk is this Thursday evening in SF. You should come!

The W600 is a new module (you can get it from Seeed, although it’s produced by Winner Micro in various formats) that is basically an ESP32, except it uses an ARM Cortex-M3 instead of a Tensilica core. [ultratechie] recently got their hands on one of these modules and got started with MicroPython. This seems like a capable module and it’s only three dollars, but will that be enough to catch up to the ESP32?

Purple gorilla enters art gallery. At the Het Nieuwe Instituut in Rotterdam there is a new exhibit featuring the, ‘destructive beauty of the computer virus’. The curators are detailing the historical progress of the computer virus from innocent DOS viruses to Melissa to Stuxnet and ransomware.

USB C has been around for a while, but 2019 is the year everything started to become USB C. Case in point: the Raspberry Pi 4. The only problem is that the Raspberry Pi Foundation messed up their implementation of USB C. Not a problem, because here’s how you design a USB C power sink. Basically, you give each CC line its own resistor. Don’t even think about it, just copy the USB C spec. You don’t know more about USB C than the people who designed it, and you’re not really saving a ton of money by deleting one resistor. Just copy the spec.

Low Res Video Card Is Still Amazing Since It’s Made Out Of Logic Chips

July 7, 2019 by 33 Comments

[Ben Eater] has been working on building computers on breadboards for a while now, alongside doing a few tutorials and guides as YouTube videos. A few enterprising hackers have already duplicated [Ben]’s efforts, but so far all of these builds are just a bunch of LEDs and switches. The next frontier is a video card, but one only capable of displaying thousands of pixels from circuitry built entirely on a breadboard.

This review begins with a review of VGA standards, eventually settling on an 800×600 resolution display with 60 MHz timing. The pixel clock of this video card is being clocked down from 40 MHz to 10 MHz, and the resulting display will have a resolution of 200×150. That’s good enough to display an image, but first [Ben] needs to get the horizontal timing right. This means a circuit to count pixels, and inject the front porch, sync pulse, and back porch at the end of each horizontal line.

To generate a single horizontal line, [Ben]’s circuit first has to count out 200 pixels, send a blanking interval, then set the sync low, and finally another blanking interval before rolling down to the next line. This is done with a series of 74LS161 binary counters set up to simply count from 0 to 264. To generate the front porch, sync, and back porch, a trio of 8-input NAND gates are set up to send a low signal at the relevant point in a horizontal scan line.

The entire build takes up four solderless breadboards and uses twenty logic chips, but this isn’t done yet: all this confabulation of chips and wires does is step through the pixel data for the horizontal and vertical lines. A VGA monitor detects it’s in the right mode, but there’s no actual data — that’ll be the focus of the next part of this build where [Ben] starts pushing pixels to a monitor.

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A Complete Desktop PCB Etching Station

July 7, 2019 by 42 Comments

Right now you can get a custom circuit board delivered to your door in about a week for just a few dollars. There’s little reason to make your own circuit boards at home anymore, but when you need a board now, you want to have that capability. [Tuval Ben Dosa] designed a complete PCB etching station that is the perfect tool for making printed circuit boards at home. It’s got everything you need for the perfect etch, and with this setup you can make a board in hours instead of waiting for days.

The chemistry for any etching setup is important, and in recent years the entire community has moved from ferric chloride to copper chloride for a very good reason: you can recharge copper chloride etchant by bubbling oxygen (or air) through it, whereas ferric chloride is a one-use etchant.

The mechanical part of this build consists of an airtight glass food container sitting on top of a PCB heating element not unlike the heated bed of a 3D printer. Along with that is an I2C temperature sensor encased in a silicone tube, a stir bar, diaphram pump, and a few pumps to blow air into the etchant and pump out the chlorine gas generated. This is controlled by a small microcontroller with a UI consisting of just an encoder and OLED display.

If you’re looking for builds that will etch copper and brass at home, this has been something that has been done before. The Etchinator is a fantastic build capable of making everything from printmaking plates to printed circuit boards. That’s a build that requires a lot of work, and this small, compact etching station does everything you need without taking up too much space in the shop. Check out the video below.

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Midiboy, The Portable Gaming Console With MIDI

July 6, 2019 by 6 Comments

The ArduBoy is a tiny little gaming console that’s also extremely simple. It’s only a small, cheap, monochrome OLED display, a microcontroller with Arduino-derived firmware, and a few buttons. That’s it, but with these simple ingredients the community around the ArduBoy has created a viable gaming platform. It has cartridges now, and one version has a crank. Now, the MIDIboy is bringing something like the ArduBoy to the world of electronic music.

Inside the MIDIboy is what you would expect from any review of the ArduBoy schematics. There are six buttons, a speaker, a USB port, and a SPI OLED display. In addition to all of this are two big chonkin’ DIN-5 ports for MIDI in and MIDI out, and yes, the MIDI in port has an optoisolator.

As for what you can do with a tiny little game console connected to MIDI, there are already a few choice apps — the MIDI Chords app creates chords, obviously, and the MIDImon sketch is a MIDI monitor. There are some controllers for MIDI synths, and of course this device is completely open source. If you’ve ever wanted a DIY controller for your favorite MIDI synth, this is what you need.

If an ArduBoy with MIDI doesn’t sound exciting, just check out Little Sound DJ. That’s a Game Boy cartridge that turns your old brick Game Boy into a music production workstation. Yes, it sounds great and there’s a lot of potential in a pocket game console with MIDI ports.

This Chiptune Player’s Got What Nintendon’t

July 6, 2019 by 7 Comments

When it comes to chiptunes, the original Nintendo Entertainment System and the Game Boy get all the accolades. The OPL synths have all the fun. But there’s another chip out there in dusty old machines that is at least as interesting with a repertoire at least as influential as the Mega Man 2 OST. It’s the YM2612, the chip in the Sega Mega Drive/Genesis.

[natalie] created a portable device capable of playing back the files targeting the sound chips in this venerable machine. It’s the MegaGRRL, and it’s the iPod for the original Genesis sound tracks.

Inside the MegaGRRL is an ESP32 in the form of an ESP-WROOM-32 module. There is, of course a YM2612 chip in there, along with a headphone amplifier and a battery charger. The display is a fairly standard and cheap affair that’s 240 x 320 pixels in full color, and there are seven buttons on this device, because of course you need an A, B, and C button.

Combined with a 3D printed enclosure, the GameGRRL does exactly what it says it will: it plays all the music from old Sega games. Now, when you’re in the inevitable argument with someone over the fact that Michael Jackson wrote the Sonic 3 soundtrack, the proof is right in your pocket. Of if you want to jam out on the Toe Jam And Earl soundtrack, that’s right there too. You can check out the video demos below.

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