Remote Control of Clocks is Easy as Pi

[Fatjedi007] recently acquired three programmable boxing gym-type clocks to help his developmentally disabled clients manage their time. The plan was to have timers of varying lengths fire at preset times throughout the day, with the large displays providing a view from anywhere. Unfortunately, the clocks were not nearly as programmable as he needed them to be.

Since he’d spent enough money already, [Fatjedi007] turned to the power of Raspberry Pi to devise an affordable solution. Each clock gets a Pi Zero W and a simple IR transmit/receive circuit that operates using LIRC. The clocks came with remote controls, so it was just a matter of re-programming them. From LIRC, he wrote some scripts with SEND_ONCE and schedules the timers with a cron job. No need to get out the ladder—he can program all of them from his chair over VNC.

He does have one problem, though, and that’s getting the Zeros to set themselves over NTP with static IPs. Do you have any suggestions? Put ’em in the comments and help a Jedi out.

LIRC is pretty handy for anything you want to control remotely, like a stereo system.

Raspberry Pi W Antenna Analysis Reveals Clever Design

The old maxim is that if you pay peanuts, you get a monkey. That’s no longer true, though: devices like the Raspberry Pi W have shown that a $10 device can be remarkably powerful if it is well designed. You might not appreciate how clever this design is sometimes, but this great analysis of the antenna of the Pi W by [Carl Turner, Senior RF Engineer at Laird Technology] might help remind you.

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Browsing Modern Day BBS on the Epson PX-8 Laptop

As you read this, there are still people chatting away on Bulletin Board Systems all over the world. Running on newly written software and without the need to actually use a dial-up modem, these (slightly) more modern takes on the BBSs of yore can be compelling diversion for those who might want to decompress a bit from contemporary social networks.

[Blake Patterson] is one of these people, and he writes in to tell us about his recent experiments with using a particularly gorgeous example the Epson PX-8 “Geneva” laptop on modernized BBSs. The form factor of the device makes it a fairly convenient client for chatting, despite the somewhat unusual screen. Luckily, modern BBS software is able to cope with the PX-8’s 80 character by 8 line LCD display, it’s just a matter of getting the thing online.

The trick is tethering the PX-8 to a Linux machine as a serial terminal. [Blake] had to build a serial cable for the laptop, and then used a basic USB-to-serial converter to get it connected to a Raspberry Pi. Once you’ve logged in over serial, you can simply fire off a telnet command to connect to the BBS of your choice. In the video after the break, he demonstrates what it’s like browsing and chatting on a BBS using the PX-8. The screen certainly takes a bit of getting used to, but actually works fairly well given the nature of the BBS interface.

[Blake] recently gave us a look at a Wi-Fi “modem” for retro computers based on the ESP8266, if you’d rather cruise your favorite BBS without a dangling Pi.

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Keeping Streets Ice-Free with the Raspberry Pi

[Revanth Kailashnath] writes in to tell us about an interesting project he and his team have been working on for their “Real Time Embedded Programming” class at the University of Glasgow. Intended to combat the harsh and dangerous winters in Glasgow, their system uses a Raspberry Pi and a suite of sensors to automatically deploy a brine solution to streets and sidewalks. While the project is still only a proof of concept and hasn’t been deployed, the work the team has done so far runs the gamut from developing their own PCBs to creating a web-based user interface.

The core idea is simple. If the conditions are right for ice to form, spray salt water. Using salt water is a cheap and safe way of clearing and preventing ice as it simply drops the temperature at which water freezes. The end result is that the ice won’t form until it gets down to 10F (-12C) or so. Not a perfect solution, but it can definitely help. Of course, you don’t want to spray people with salt water as they pass by, so there’s a bit more to it than that.

Using the venerable DHT22 sensor the team can get the current temperature and humidity, which allows them to determine when it’s time to start spraying. But to prevent any wet and angry pedestrians, a HC-SR501 PIR motion sensor is used. If the system sees motion it will stop for a while to let the activity quiet down.

Monitoring the sensors and controlling the pump is done by a daemon written in C++, which also logs data to an SQL database, which in turn feeds their PHP web interface. In the video after the break, [Revanth] demonstrates how the system is constantly making decisions based on the input of the various sensors. Environmental data and motion is analysed every few seconds to provide a real-time solution.

We’ve covered a few projects aimed at melting ice and snow by heating concrete, but it’s interesting to see a “smart” approach to this common winter annoyance.

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Polaroid Gets Thermal Printer and Raspberry Pi

Despite what you may have read in the comments, we here at Hackaday are not unaware that there’s something of a “Pi Fatigue” brewing. Similar to how “Arduino” was once a dirty word around these parts, projects that are built around the world’s most popular Linux SBC are occasionally getting dismissed as lazy. Hacker crams Raspberry Pi into an old electronic device, applies hot glue liberally, posts a gallery on Imgur, and boom! Lather, rinse, repeat.

We only mention this because the following project, despite featuring the Raspberry Pi Zero grafted into a vintage Polaroid camera, is anything but lazy. In the impeccably detailed and photographed write-up, [mitxela] explains how the Pi Zero and a thermal camera recreated the classic Polaroid experience of going from shutter button to physical picture in seconds. The workmanship and attention to detail on this build is simply phenomenal, and should quell any doubts our Dear Readers may have about Raspberry Pi projects. For now, anyway.

The video after the break will show you the modded camera in operation and goes over a few highlights of the build, but for this one you really should take the time to read the entire process start to finish. [mitxela] starts off by disassembling the Polaroid camera, complete with plenty of fantastic pictures that show how this legendary piece of consumer electronics was put together. If you’ve never seen the inside of one of these cameras, you might be surprised to see what kind of interesting hardware is lurking underneath that rather unassuming exterior. From the screw-less construction to the circuits with paper substrate, a lot of fascinating engineering went into getting this camera to a mass-market price. Frankly, the teardown alone is worth checking out.

But once the camera has been stripped down to the bare frame, the real fun begins. At the conceptual level, [mitxela] replaces the camera optics with a cheap webcam, the “brains” with a Raspberry Pi Zero, and the film mechanism with the type of thermal printer used for receipts. But how he got it all connected is why this project is so impressive. Nearly every decision made during the design and construction of this camera was for the purposes of reducing boot-time. Nobody wants a camera that takes 30, 15, or even 10 seconds to boot. It has to be available as soon as you need it.

Getting this Linux-powered camera boot up in as little as 2 seconds took a lot of clever software hacks that you’ll absolutely want to check out if you’ve ever considered building an embedded Linux device. You can’t just throw a stock Raspbian image on an SD card and hope for the best. [mitxela] used buildroot to craft a custom Linux image containing only what was needed for the camera to operate, plus a bunch of esoteric tweaks that the Junior Penguin Wrangler would likely never consider. Like shaving a full second off of the boot time by disabling dumping kernel messages to the serial port during startup.

[mitxela] brought his camera to show off at the recent Hackaday London meetup, but it was far from the first time we’ve come across his handiwork. From his servo-powered music box earlier this year to his penchant for tiny MIDI devices, he’s consistently impressed our cold robot hearts.

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Visualizing Blocked Ads with the Pi Sense Hat

Pi-hole is an open source project to turn that Raspberry Pi collecting dust in your drawer into a whole-network ad blocking appliance. Not only does it stop ads from showing up on all your computers and mobile devices, it also keeps track of how many ads have been blocked and where they came from. Just in case you wanted to know how many thousands of ads you missed out on for a given time period.

While the graphs generated in the web interface of Pi-hole are slick and all, what if you just wanted a quick way of visualizing how effective your ad blocking system is? You’re not so much worried about the exact figures, you just want something to blink away on your desk and let you know all those ads are going to /dev/null. Enter the aptly named pi-hole-visualizer by [simianAstronaut].

With the addition of a Sense HAT to the Pi running the ad blocking, this Python script will generate an animated visualization that can be easily interpreted even from a distance. The primary display is a bar graph of DNS traffic, where the height and color of each column indicate relative activity within a specific time interval. A second screen shows a spiral graph which gives you an idea of what percentage of ads were blocked before they hit your devices.

An array of options can be given to the script from the command line; controlling both physical aspects of the display like orientation and LED brightness, as well the configurable parameters for the different available visualizations. As an added bonus, there’s also support for using the Sense HAT joystick to switch between modes interactively.

Turning the Raspberry Pi into an ad blocking appliance goes back to the olden days of the original Raspberry Pi, but it’s interesting to see how advanced the concept has become. Just remember, not all ads are bad.

The Raspberry Pi 3B+ As An SDR – Without The SDR!

We’ve become used to software-defined radio as the future of radio experimentation, and many of us will have some form of SDR hardware. From the $10 RTL USB sticks through to all-singing, all-dancing models at eye-watering prices, there is an SDR for everyone.

What about the idea of an SDR without any external hardware? Instead of plugging something into your Raspberry Pi, how about using the Pi itself, unmodified? That’s just what the Nexmon SDR project has achieved, and this has been made possible through clever use of the on-board Broadcom 802.11ac WiFi chip. The result is a TX-capable SDR, albeit one only capable of operating within the 2.4 GHz and 5 GHz spectrum used by WiFi.

The team had previously worked extensively with the chipset in the Nexus 5 phone, and the SDR extension was first available on that platform. Then along came the Raspberry Pi 3 B+ with a similar-enough WiFi chipset that the same hack was portable to that platform, et voilá: WiFi SDR on a Pi 3 B+.

If you’ve not looked at the Pi 3 B+ we’d like to direct you to our review. If you don’t have a Nexus 5 kicking around, and you’d like to do some WiFi-band SDR work, it’s looking like an amazing deal.

Via rtl-sdr.com.