serial

182 Articles

Upgrade Board Turns Typewriter Into A Teletype

November 14, 2019 by 24 Comments

It may come as little surprise to find that Hackaday does not often play host to typewriter projects. While these iconic machines have their own particular charm, they generally don’t allow for much in the way of hardware modification. But then the IBM Wheelwriter 1000 isn’t exactly a traditional typewriter, which made its recent conversion to a fully functional computer terminal possible.

A product of the Computer History Museum’s [IBM 1620 Jr. Team], this modification takes the form of a serial interface board that can be built at home and installed into the Wheelwriter. The board allows the vintage electronic typewriter to speak RS-232 and USB, so it can be connected to whatever vintage (or not so vintage) computer you can imagine. The documentation for the project gives a rough cost of $150, though that does assume you’ve already got a Wheelwriter 1000 kicking around.

The GitHub repository includes everything you need to create your own board, and there’s even a highly detailed installation guide that goes over the case modifications necessary to get the new hardware installed. It also explains that you’ll want to get a new keycap set for your Wheelwriter if you perform this modification, as the original board doesn’t have all of the ASCII characters.

So why adapt an old electric typewriter to function as a teletype? As explained by the [IBM 1620 Jr. Team], there are projects out there looking to recreate authentic 1960s-era computing experiences that need a (relatively) affordable paper terminal. The originals are too rare to use in modern recreations, but with their adapter board, these slightly less archaic input devices can be used in their place.

Once you’ve built your new teletype, or in the somewhat unlikely event you already have one at the ready, we’ve seen a couple of projects that you might be interested in to put it to use.

Reverse Engineering A Two-Wire Intercom

October 27, 2019 by 13 Comments

There was a time when an intercom was simply a pair of boxes with speakers joined by a couple of wires, with an audio amplifier somewhere in the mix. But intercoms have like everything else joined the digital age, so those two wires now carry a load of other functionality as digital signalling. [Aaron Christophel] installs these devices for a living, and has posted a fascinating reverse engineering video that we’ve also placed below the break.

Power for the system is present as a constant 24V DC, and the audio is still an old-fashioned analogue signal that we’ll all be familiar with. On that 24V DC though are imposed a series of pulse trains to trigger the different alarms and other functions, and he describes extracting these with an oscilloscope before showing us the circuitry he’s used to send and receive pulses with an Arduino. The bulk of the video is then devoted to the software on the Arduino, which you can also find in a GitHub repository.

The result is an interesting primer for anyone who fancies a bit of serial detective work, even if they don’t have a intercom to hand.

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2D-Scanner Records Surfboard Profiles For Posterity

October 6, 2019 by 5 Comments

[Ryan Schenk] had a problem: he built the perfect surfboard. Normally that wouldn’t present a problem, but in this case, it did because [Ryan] had no idea how he carved the gentle curves on the bottom of the board. So he built this homebrew 2D-scanner to make the job of replicating his hand-carved board a bit easier.

Dubbed the Scanbot 69420 – interpretation of the number is left as an exercise for the reader, my dude – the scanner is pretty simple. It’s just an old mouse carrying a digital dial indicator from Harbor Freight. The mouse was gutted, with even the original ball replaced by an RC plane wheel. The optical encoder and buttons were hooked to an Arduino, as was the serial output of the dial indicator. The Arduino consolidates the data from both sensors and sends a stream of X- and Z-axis coordinates up the USB cable as the rig slides across the board on a straightedge. On the PC side, a Node.js program turns the raw data into a vector drawing that represents the profile of the board at that point. Curves are captured at various points along the length of the board, resulting in a series of curves that can be used to replicate the board.

Yes, this could have been done with a straightedge, a ruler, and a pencil and paper – or perhaps with a hacked set of calipers – but that wouldn’t be nearly as much fun. And we can certainly see applications for this far beyond the surfboard shop.

Tinker Pilot Project Cranks Cockpit Immersion To 11

September 25, 2019 by 1 Comment

One of the more interesting ideas being experimented with in VR is 1:1 mapping of virtual and real-world objects, so that virtual representations can have physically interaction in a normal way. Tinker Pilot is a VR spaceship simulator project by [LLUÍS and JAVI] that takes this idea and runs with it, aiming for the ability to map a cockpit’s joysticks, switches, and other hardware to real-world representations. What does that mean? It means a virtual cockpit with flight sticks, levers, and switches that have working physical versions that actually exist exactly where they appear to be.

A few things about the project design caught our eye. One is the serial communications protocol intended to interface easily with microcontrollers, allowing for feedback between the program and any custom peripherals. (By the way, this is the same approach Kerbal Space Program took with KSPSerialIO, which enables custom mission control hardware at whatever level of complexity a user may wish to implement.)

The possibilities are demonstrated starting around 1:09 in the teaser trailer (embedded below) in which a custom controller is drawn up in CAD, then 3D-printed and attached to an Arduino, and finally the 3D model is imported into the cockpit as a 1:1 representation of the actual working unit, with visual positional feedback.

Unlike this chair experiment we saw which attached a Vive Tracker to a chair, there is no indication of needing positional trackers on individual controls in Tinker Pilot. In a cockpit layout, controls can be reasonably expected to remain in fixed positions relative to the cockpit, meaning that they can be set up as 1:1 representations of a physical layout and otherwise left alone. The kind of experimentation that is available today even to individual developers or small teams is remarkable, and it’s fascinating to see the ideas being given some experimentation.

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Hacked Calipers Make Automated Measurements A Breeze

July 4, 2019 by 21 Comments

Now, digital calipers with wired interfaces to capture the current reading are nothing new. But the good ones are expensive, and really, where’s the fun in plugging a $75 cable into a computer? So when [Max Holliday] was asked to trick out some calipers for automating data capture, he had to get creative.

[Max] found that cheap Harbor Freight digital calipers have the telltale door that covers a serial connector, making them a perfect target for hacking. A little Internet sleuthing revealed the pinout for the connector as well as some details on the serial protocol used by most digital calipers: 24-bit packets is six four-bit words. [Max] used his SAM32, a neat open-source board with both a SAMD51 and an ESP32 that can run CircuitPython. An inverting buffer interfaces the serial lines to the board, which is just the right size to mount on the back of the caliper head. It’s hard to tell how [Max] is triggering readings, but the SAM32 is mounted as a USB device and sends keystrokes directly to a spreadsheet – yes, with the ESP32 it could have been wireless, but his client specifically requested a wired setup. Taking multiple readings is easy now that the user never has to swap calipers for a pen.

Cheap calipers like these are pretty hackable – you can add Bluetooth, turn them into DROs for a milling machine, or even make them talk.

Vintage Speech Synthesizer Croons The Oldies

June 11, 2019 by 33 Comments

If you listened to the National Weather Service Weather Radio in the US about 25 years ago, you’ll no doubt remember [Perfect Paul], one of the synthesized voices used to read current conditions and weather forecasts. The voice came from a DECtalk DTC01, a not inexpensive voice synthesizer first made in 1984 that also gave voice to [Stephen Hawking] for many years.

Long obsolete, the DECtalk boxes have a devoted following with hobbyists who like to stretch what the device can do. Some even like to make it sing, after a fashion, and [Michael] decided that making a DECtalk sing “Xanadu”, the theme song from the 1980 [Olivia Newton-John] musical extravaganza, was a good idea. Whether it actually was is debatable, and we’ll take exception with having that particular ditty stuck in our head as a result, but we don’t judge except on the merits of the hack.

It’s actually easy if you have a DECtalk; the song is a straight ASCII file with remarkably concise instructions on which phonemes the box needs to generate. Along with inflection, tone, and timing instructions, the text file looks almost completely unlike English while still somehow being readable. The DECtalk accepts the file over RS-232, which would be easy enough to do with a modern computer, but [Michael] upped his game a bit by using a TRS-80 Model 100 computer as a serial terminal. The synthesized song is in the video below, with the original included for reference by those who didn’t experience endure the late disco-era glory days.

DECtalks seem pretty rare in the wild, so we appreciate this glimpse at what they can do. There are other retro speech synthesizer hacks, though: the simulated walnut goodness of the Votrax and the MicroVox come to mind, as does the venerable TI Speak and Spell.

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SerialPlot Does Exactly What You Think It Does

May 30, 2019 by 12 Comments

The serial port remains a hacker staple, being one of the easiest ways to move a little bit of data from one machine to another. All manner of projects use the interface, and often, sensors are connected and their data read over such connections. In these cases, it can be useful to plot said data, and SerialPlot is a tool that can do just that.

SerialPlot is capable of reading data over several serial ports at once, and plotting it for your viewing pleasure. It’s capable of interpreting data in a variety of integer and float formats, and plotting multiple channels in a synchronised manner. It’s also capable of sending basic commands out over the serial port, which can be used to trigger or control attached equipment.

Overall, it’s a useful utility for anyone with an array of sensor’s connected over the most classic of interfaces. Of course, if you’re having trouble keeping track of all your serial ports, there’s a utility to help with that, too.