Broadcast Engineer at BellMedia, Computer history buff, compulsive deprecated, disparate hardware hoarder, R/C, robots, arduino, RF, and everything in between.
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Here's the pen cartoonist Tom Gauld uses

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Tom Gauld is one of my favorite cartoonists. (see my reviews of his previous books, Mooncop, You're All Just Jealous of my Jetpack, Goliath, and The Gigantic Robot).

 

I met him a couple of years ago and he gave me the pen he uses to draw his cartoons: the Pilot Precise V5 Roller Ball Stick Pen. It makes a very clean line, and Tom told me the ink does not fade, even after many years. Now that I've started sketching again (I post some of my sketches on my Instagram account), I was reminded of Tom's pen and reordered a box.

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tekvax
4 days ago
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these are awesome pens!they got me through 7 years of college!
Burlington, Ontario
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Man at airport gets more video game space by plugging PS4 into public map display

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A guy who was waiting for his flight at the airport in Portland wanted more screen display space for his Playstation video game session, so he plugged his PS4 into a public computer screen that was displaying a map of the airport.

Airport staff were not amused.

Port of Portland spokesperson Kara Simonds told Portland KXL-AM radio that staff at Portland International Airport staff asked the man to stop gaming on the public map display.

The man asked if he could finish his game.

They said no.

The situation resolved peacefully.

From the Associated Press:

“Apparently it was a very polite and cordial interaction,” Simonds said, calling it “a good reminder of what not to do at the airport.”

No word on whether or not the passenger made it to the next level.

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tekvax
5 days ago
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you go gamer!
Burlington, Ontario
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Numitron Clock Is A Tidy ’70s Throwback

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As far as hacker clock builds go, the more obscure the parts involved, the better. By this yardstick, [sjm4306] has a great piece on his hands with this Numitron-based build.

The Numitron was a type of display popular in the 1970s, and often used in aircraft avionics and other high-end hardware. The display is a 7-segment type, but using filaments instead of LEDs. [sjm4306] was able to lay his hands on four of these devices, along with some bulbs to act as the digit seperator and AM/PM indicator. Due to being incandescent in nature, multiplexing wasn’t a practical option, with lower duty cycles drastically dimming the display. Instead, a 32-bit cascaded shift register was used to enable all the segments to be driven at the same time.

It’s a great build that uses some genuine original display hardware to create a clock with a compelling vintage aesthetic. This would make a great gift to a pilot from the era, or any hacker that likes the unusual display technologies of yesteryear. You can even build a Numitron watch, if you’re so inclined. Video after the break.

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tekvax
7 days ago
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Burlington, Ontario
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Linux Fu: Stupid SSH Tricks

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If you connect to remote computers over the Internet, it is a pretty good chance you use some form of SSH or secure shell. On Linux or Unix you’ll use the ssh command. Same goes for Linux-like environments on Windows like Cygwin or WSL. For native Windows, you might be using Putty. In its simplest form, ssh is just a terminal program that talks to a server using an encrypted connection. We think it is very hard to eavesdrop on anyone communicating with a remote computer via ssh.

There are several tricks for using ssh — some are pretty straightforward and some are things you might not think of as being in the domain of a terminal program. You probably know that ssh can copy files securely, and there are easy and hard ways to set up logging in with no password.

However, you can also mount a remote filesystem via ssh (actually, there are several ways to do that). You can use ssh to securely browse the web in your favorite browser, or even use it to tunnel specific traffic by port or even use it as a makeshift VPN. In fact, there’s so much ground to cover that this won’t be the last Linux Fu to talk about ssh. But enough setup, let’s get to the tricks.

A Few Good Options

We’ll assume you know the basics: scp and sftp for file copies and ssh-copy-id for setting up password-less login. (If not, you have ten minutes to do a quick web search.) But one of the things ssh is great at is manipulating the network. Keep in mind, though, that the server has to have certain options set to do some of the most interesting things, so if you don’t control the ssh server, some of these tricks might not work for you.

There are a lot of options to remember on the ssh command line, but luckily you don’t have to. You don’t even have to remember your hostname or user name. In the ~/.ssh/config file you can create an alias. For example, suppose you want to connect to your home server:

Host homeserver
  HostName mih0me.dyndns.org
  Port 1234
  User TheAl
  IdentityFile ~/.ssh/home_id
  ForwardX11 yes
  Compression yes
  TCPKeepAlive yes

You can have as many aliases as you like. Just keep repeating the Host line and then follow it with options. You can also add more than one alias to a single Host statement. The subsequent options will then apply to any of the aliases. Now to connect just issues ssh homeserver and you are in with all the right options.

Of course, if you are using Putty, your options will mainly be in the host profile and on the ssh panel of the options screen. You might not get as many options, but there are some you can try.

Be Persistent

One really nice set of options to include set the master control file. For example:

ControlMaster auto
ControlPath ~/.ssh/master-%r@%h:%p

This lets multiple sessions to the same host share a single TCP socket. Because it takes a some time to set up a secure socket, this can be speed things up if you keep several sessions going between two hosts. You can set it for all hosts by using the Host * line in the config file. You can use that for any global options you might have.

On the other hand, if you shove a lot of data over multiple connections, turning on ControlMaster might not be a great idea. You can add -S none to override the global setting.

One other thing to note is that your first ssh session might appear to hang if you try to exit it before all the other connections are closed. Some people deliberately run a hidden ssh session on login to a host they often connect to which avoids that problem. However, a better way is to set ControlPersist to yes. That will cause the original session to go to the background indefinitely. If you want a little grace period you can set ControlPersist to a number like 180. That would cause the background session to end if there are no connections for three minutes.

Another downside to this approach is that you tend to get orphaned master files. In rc.local I have the following line:


/bin/rm /home/*/.ssh/master-* || true >/dev/null

 

With Putty, you can click the “Share SSH connections if possible” button in the SSH options panel.

Configuration

There are quite a few configuration options you can use in the config file. For example, BatchMode lets you tell ssh the connection is made for unattended use so don’t bother prompting the user for passwords or anything else. That’s not to say it will just let you in, of course. It just means it will fail if you don’t have things set up to login without a password.

There are some other interesting items. For example, you can run a local or remote command on connection. You can also send an environment variable to the remote host or even just set one. For example, suppose you want to always keep your LS_COLORS the same on your workstation and the server, but you frequently change them and don’t want to use the same profiles.  You could add this to the host’s config file entry:


SendEnv LS_COLORS

The server has to be configured to accept this, of course. Putty can handle setting an environment variable from the Data tab in its setup.

On the network side, you can specify TCPKeepAlive to yes if you want the server and client to test their connection during idle periods. This is a two-edged sword. If the connection is idle, you won’t get disconnected. But if the network drops at the right moment for a brief period you might get disconnected where you wouldn’t have if you had stuck with the default. There’s even a way to open a layer 3 or layer 2 tunnel between the machines — a topic for a future Linux Fu.

By Your Command

Don’t forget that ssh can execute a command and send its output to you. As a practical example, I occasionally reflash my 3D printer firmware. The printer is connected to a Raspberry Pi, but I do the firmware build on my main machine. For a long time, I copied my file to the Pi (using scp) and then logged into the Pi to run a script I wrote called flash. The script disables the Reptier server software, flashes the Atmel chip on the printer control board, and then turns the server back on.

Here’s the script that runs on my main computer. Note the ssh commands. One turns off the server. One scp command copies the new firmware over. Then another ssh does the flash and renables the server. There are many other ways to do this, of course. But don’t forget that ssh can run a remote command and then return.


#!/bin/bash
if [ -z "$1" ]
then
  echo Usage: flash hexfile [remote_name]
  echo If omitted, remote_name will have date attached
  exit 1
fi
ONAME="$2"
EXTRA=$(date "+%Y%m%d.%H%M")
if [ -z "$2" ]
then
  ONAME="$1-$EXTRA.hex"
fi
IP=192.168.1.110
  echo Stop Server
  ssh -l pi $IP "sudo systemctl stop RepetierServer"
  echo Copy...
  scp "$1" "pi@$IP:a8fw/$ONAME"
  echo Flashing...
ssh pi@$IP "cd a8fw; ./flash $ONAME"
echo Restart
ssh "pi@$IP" "sudo systemctl start RepetierServer"
echo Done
exit 0

If you want a more hacker-friendly example, consider using the same idea to run Wireshark locally and analyze a remote packet capture:


ssh root@someserver 'tcpdump -c 1000 -nn -w - not port 22' | wireshark -k -i -

You can do the same trick with tshark, if you prefer.

Speed Test

What to know how fast your ssh connection is? Make sure you have pv installed and try this:

yes | pv | ssh remote_host "cat >/dev/null"

Pretty cool!

If you have good speeds — or even if you don’t — you can try mounting a remote file system using sshfs. This is a FUSE filesystem — that is, a filesystem that lives as a regular user program, not part of the kernel. With nothing on the remote side but the ssh server and standard tools, you can make any host you can connect to look like a local file system.

But Wait…

There’s a lot more you can do with ssh, and I’ll cover more shortly. But for now, hopefully you found at least one ssh trick you can use that was, if not new, at least a reminder for you.

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tekvax
7 days ago
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Burlington, Ontario
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A Nixie Radio Clock Fit For a Victorian Mad Scientist

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[Ioszelos] built a nixie clock with a dizzying array of features.

Do you ever wish that you could log in to your clock from your phone and turn off your TV? We assume that [Ioszelos] did. The clock can also play MP3s and stream radio stations. It can record the indoor temperature, humidity, and barometric pressure. Did we mention it’s an FM radio too? We’re not sure, but we wouldn’t be surprised if there was a faucet hiding somewhere on the contraption.

A team effort shared between an ESP32 and Mega 2560 run the Rube Goldberg-like show. Custom boards were spun up to provide the control and voltages needed for the nixie tubes. The clock is constructed from machined plates and 3D printed files.

It all comes together in a steampunk reminiscent assembly. The glow from the RGB leds and nixie tubes combine to make an interesting visual effect. We’ve certainly never seen a clock quite like it before.

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tekvax
7 days ago
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Burlington, Ontario
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Commodore Tape Drive Emulator On A Raspberry Pi

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We imagine most of the people reading Hackaday have an old Raspberry Pi or two laying around. It’s somewhat less likely you’ve still got an 8-bit Commodore in working condition, but we’d wager there’s more than a few in the audience that can count themselves among both groups. So why not introduce them?

[RhinoDevel] writes in to tell us about CBM Tape Pi , an open source Commodore tape drive emulator for Raspberry Pi that needs only a handful of passive components to get wired up. Even better, the project targets the older Pis that are more likely to be languishing around in the parts bin. In the video after the break, a Commodore PET can be seen happily loading content from the original Raspberry Pi with its quaint little composite video connector.

Without any special software on the Commodore itself, the project allows the user to load and save PRGs on the Pi’s SD card, as well as traverse directories. Don’t expect stellar I/O, as [RhinoDevel] notes that no fast loader is currently implemented. Of course if you’re enough of a devotee to still be poking around a VIC-20 or C64 this far into 21st century, then we imagine you’ve got enough patience to get by.

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tekvax
7 days ago
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Burlington, Ontario
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