8-Channel ADC For the Raspberry Pi

The Raspberry Pi is a powerful embedded computing platform. However, for all its Linux-based muscle, it lacks one thing that even the simplest 8-bit microcontrollers usually have – analog-to-digital conversion. There are a great many ways to rectify this shortcoming, and [Chris Burgess] has brought us another – with an 8-channel ADC for the Raspberry Pi.

For the ADC, [Chris] chose the MCP3008, for its low cost and availability. In this configuration it offers 10-bit resolution and a maximum sampling rate of 200 kilosamples per second. Adafruit has a great guide on working with the MCP3008, too. With such a useful resource to hand, [Chris] was able to spin up a PCB to interface the chip to the Raspberry Pi using SPI. [Chris] took care to try to make the board to the official HAT specifications. As far as the physical aspects go, the board is to spec, however [Chris] omitted the EEPROM required for auto-configuration purposes. That said, the pads are on the board if someone wants to take the initiative to install one.

It’s a tidy build that provides something sorely missing from the Raspberry Pi, for a reasonable cost. [Chris]’s goal was to build something that would enable the measurement of analog sensors for a robot project; we’d love to hear your ideas for potential uses in the comments!

Old Intercom Gets Googled with Raspberry Pi and AIY Hat

Old Radio Shack intercom; brand new Google Voice interface for a Raspberry Pi. One of these things is not like the other, but they ended up together in this retro-look Google Voice interface, and the results are pretty slick.

The recipient of the Google hive-mind transplant was one of three wireless FM intercoms [MisterM] scored for a measly £4. Looking much as they did when they were the must-have office tool or home accessory for your modern mid-80s lifestyle, the intercom case was the perfect host for the Pi and the Google AIY hat. Only the case was used — not even the original speaker made it into the finished product. The case got a good scrubbing, a fresh coat of paint to perk up the gone-green plastic, and an accent strip of Google’s logo colors over the now-deprecated station selector switch. [MisterM] provided a white LED behind the speaker grille for subtle feedback. A tap of the original talk bar gets Google’s attention for answers to quick questions, and integration into the family’s existing home automation platform turns the lights on and off. See it in action after the break.

[MisterM] was lucky enough to score an AIY hat for free, and as far as we know they’re still hard to come by. If you’re itching to try out the board, fear not — turns out you can roll your own.

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3.3V Is Not Enough for This Raspberry Pi Zero

A Raspberry Pi Zero is down to a price and size where it’s just begging to be integrated into your projects. Unless, that is, if your project involves a lot of 5 V equipment. Then it’s just begging to be fried.

[David Brown] solved this problem by breaking out pins with level converters. He used flat-flex cable and some pin-headers. While he was at it, he added a full-sized USB port and power headers. (Extra hack points are awarded for connecting the USB to the board through pogo pins.)

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Kansas City Maker Faire: Pi-Plates

As soon as he spied the Jolly Wrencher on my shirt, [Jerry Wasinger] beckoned me toward his booth at Kansas City Maker Faire. Honestly, though, I was already drawn in. [Jerry] had set up some interactive displays that demonstrate the virtues of his Pi-Plates—Raspberry Pi expansion boards that follow the HAT spec and are compatible with all flavors of Pi without following the HAT spec. Why not? Because it doesn’t allow for stacking the boards.

[Jerry] has developed three types of Pi-Plates to date. There’s a relay controller with seven slots, a data acquisition and controller combo board, and a motor controller that can handle two steppers or up to four DC motors. The main image shows the data acquisition board controlling a fan and some lights while it gathers distance sensor data and takes the temperature of the Faire.

The best part about these boards is that you can stack them and use up to eight of any one type. For the motor controller, that’s 16 steppers or 32 DC motors. But wait, there’s more: you can still stack up to eight each of the other two kinds of boards and put them in any order you want. That means you could run all those motors and simultaneously control several voltages or gather a lot of data points with a single Pi.

The Pi-Plates are available from [Jerry]’s site, both singly and in kits that include an acrylic base plate, a proto plate, and all the hardware and standoffs needed to stack everything together.

Stepping out in Style with Top Hat Navigation

Wearable tech is getting to be a big thing. But how we interface with this gear is still a bit of a work in progress. To explore this space, [Bruce Land]’s microcontroller course students came up with an acoustic interface to assist with navigation while walking. With style, of course.

[Bruce], from the Cornell University School of Electrical and Computer Engineering, has been burning up the Hackaday tips line with his students’ final projects. Here’s the overview page for the Sound Navigation Hat. It uses a PIC32 with GPS and compass. A lot of time was spent figuring out how to properly retrieve and parse the GPS data, but for us the interesting bits on that page are how the directional sound was put together.

Audio tones are fed to earbuds with phase shift and amplitude to make it seem like the sound is coming from the direction you’re supposed to walk. Navigation is all based on pre-programmed routes which are selected using a small LCD screen and buttons. One thing’s for sure, the choice of headwear for the project is beyond reproach from a fashion standpoint – engineering has a long history with the top hat, and we think it’s high time it made a comeback.

Is this a practical solution to land navigation? Of course not. But it could be implemented in smartphone audio players for ambient turn-by-turn navigation. And as a student project, it’s a fun way to demonstrate a novel interface. We recently covered a haptic navigation interface for the visually impaired that uses a similar principle. It’ll be interesting to see if either of these interfaces goes anywhere.

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Because Burning Man Needed More LEDs

There are a lot of blinky glowy things at Burning Man every year, and [Mark] decided he would literally throw his hat into the ring. He built a high visibility top hat studded with more RGB LEDs than common sense would dictate. It’s a flashy hat, and a very good example of the fashion statement a few hundred LEDs can make.

[Mark]’s top hat has 481 WS2812b addressable LEDs studded around the perimeter, a common LED choice for bright and blinky wearables. These LEDs are driven by a Teensy 3.1, with a Bluetooth transceiver, a GPS module, a compass, and gyro/accelerometer attached to the microcontroller. That’s a lot of hardware, but it gives [Mark] the capability of having the hat react to its own orientation, point itself North, and allow for control via a modified Nintendo NES controller.

The WS2812 LEDs draw a lot of power, and for any wearable project having portable power is a chief concern. [Mark]’s original plan was to use an 8x battery holder for the electronics enclosure, and use five AA batteries to power the hat. The total idle draw of the LEDs was 4.5 Watts, and with even a few LEDs blinking colors there was a significant voltage drop. The idea of powering the hat with AA batteries was discarded and the power source was changed to a 195 Watt-hour lithium ion battery bank that was topped off each day with a solar panel.

The hat is awesome, exceedingly bright, and something that gets a lot of attention everywhere  it goes. For indoor use, it might be too bright, but this could be fixed with the addition of a bit of black stretchy fabric, like what our own [Mike Szczys] did for his DEF CON hat. [Mark]’s hat is just version 1, and he plans on making a second LED hat for next year.

Closing out DEF CON 23

We had a wild time at DEF CON last week. Here’s a look back on everything that happened.

defcon-23-hackday-breakfast-thumbFor us, the festivities closed out with a Hackaday Breakfast Meetup on Sunday morning. Usually we’d find a bar and have people congregate in the evening but there are so many parties at this conference (official and unofficial) that we didn’t want people to have to choose between them. Instead, we made people shake off the hangover and get out of bed in time for the 10:30am event.

We had a great group show up and many of them brought hardware with them. [TrueControl] spilled all the beans about the hardware and software design of this year’s Whiskey Pirate badge. This was by far my favorite unofficial badge of the conference… I made a post covering all the badges I could find over the weekend.

We had about thirty people roll through and many of them stayed for two hours. A big thanks to Supplyframe, Hackaday’s parent company, for picking up the breakfast check and for making trips like this possible for the Hackaday crew.

Hat Hacking

For DEF CON 22 I built a hat that scrolls messages and also serves as a simple WiFi-based crypto game. Log onto the access point and try to load any webpage and you’ll be greeted with the scoreboard shown above. Crack any of the hashes and you can log into the hat, put your name on the scoreboard, and make the hat say anything you want.

Last year only one person hacked the hat, this year there were 7 names on the scoreboard for a total of 22 cracked hashes. Nice work!

  • erich_jjyaco_cpp    16 Accounts
  • UniversityOfAriz     1 Account
  • @badgerops             1 Account
  • conorpp_VT             1 Account
  • C0D3X Pwnd you    1 Account
  • D0ubleN                   1 Account
  • erichahn525_VTe     1 Account

Three of these hackers talked to me, the other four were covert about their hat hacking. The top scorer used a shell script to automate logging-in with the cracked passwords and putting his name on the scoreboard.

I’d really like to change it up next year. Perhaps three hats worn by three people who involves some type of 3-part key to add different challenges to this. If you have any ideas I’d love to hear them below, or as comments on the project page.

[Eric Evenchick] on socketCAN

eric-evenchick-socketCAN-defcon-23-croppedOne of the “village” talks that I really enjoyed was from [Eric Evenchick]. He’s been a writer here for a few years, but his serious engineering life is gobbling up more and more of his time — good for him!

You probably remember the CANtact tool he built to bring car hacking into Open Source. Since then he’s been all over the place giving talks about it. This includes Blackhat Asia earlier in the year (here are the slides), and a talk at BlackHat a few days before DEF CON.

This village talk wasn’t the same as those, instead he focused on showing what socketCAN is capable of and how you might use it in your own hacking. This is an open source software suite that is in the Linux repos. It provides a range of tools that let you listen in on CAN packets, record them, and send them out to your own car. It was great to hear [Eric] rattle off examples of when each would be useful.

Our Posts from DEF CON 23

If you missed any of them, here’s our coverage from the conference. We had a blast and are looking forward to seeing everyone there next year!