Building The DIY HP41C: A Field Report

December 3, 2021 by Al Williams 20 Comments

I have a confession to make. I write about a lot of projects for Hackaday, but there are very few I read about and then go actually build a copy of it. I don’t have a lot of time and I’m usually too busy building my own stuff. But once in a while, something strikes my fancy and I’ll either raid the junk box or buy the kit. The most recent case of that was the PX-41C, a replica of the classic HP-41C.

The HP-41C is a somewhat legendary reverse-polish notation calculator. I still have my original HP-41C from 1979 (a very low serial number). It is still a workhorse but at 43 years old or so, I don’t like to leave it hanging around or near anything that might damage it. It has enough wear from the daily use it received 40 years ago. Sure, I have great emulation on my phone and I use that too, but the PX-41C kit looked fun, and with all through-hole parts it would be a quick build. The black Friday sale on Tindie sealed the deal for me.

Start-Up

The kit arrived on the Saturday after Thanksgiving, I decided to tackle it while waiting for some 3D prints. The components were all nicely bagged and marked. Tearing into the bags was a bit frustrating, but not hard and it did keep everything separate. There was a bill of materials, but — I thought — no instructions. Turns out the last part of the bill of materials is a link to some instructions. They aren’t much and I didn’t realize they were until after completing the board, but it isn’t hard to figure out. All the parts are marked on the silkscreen and you can probably figure it out — with a few caveats.

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Hackable Ham Radio Multitool Contributes To Long Term Survival Of The Hobby

September 18, 2019 by Danie Conradie 28 Comments

Ham radio, especially the HF bands, can be intimidating for aspiring operators, many being put off by the cost of equipment. The transceiver itself is only part of the equation and proper test and measurement equipment can easily add hundreds of dollars to the bill. However, such equipment goes a long way to ease the frustrations of setting up a usable station. Fortunately [Ashhar Farhan, VU2ESE] has been at it again, and recently released the Antuino, an affordable, hackable test instrument for ham radio and general lab for use.

As you can probably guess from the name, it is primarily intended for testing antennas, and uses an Arduino Nano as a controller. It has quite a list of measurement functions including SWR, field strength, cable loss, RF cable velocity, modulation, and frequency response plotting. It also provides a signal source for testing. Its frequency range includes the HF and VHF bands, and it can even work in the UHF bands (435Mhz) if you are willing to sacrifice some sensitivity. The software is open source and available with the schematics on Github.

Most of the active ham radio operators today are of the grey haired, retired variety. If the hobby is to stand any chance of outliving them, it needs to find a way to be attractive to the younger generations who grew up with the internet. The availability of affordable and hackable equipment can go long way to making this happen, and [Ashhar Farhan] has been one of the biggest contributors in this regard. His $129 μBITX HF SSB/CW transceiver kit is by far the best value for money general coverage HF radio available.

See a short demonstration of the Antuino video after the break

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You Can Learn A Lot From A Blinkenrocket

February 2, 2018 by Elliot Williams 8 Comments

At this year’s Chaos Communication Congress, we caught up with [muzy] and [overflo], who were there with a badge and soldering project they designed to teach young folks how to solder and program. Blinkenrocket is a basically a 64-LED matrix display and just enough support hardware to store and display animations, and judging by the number of blinking rockets we saw around the necks of attendees, it was a success.

Their talk at 34C3 mostly concerns the production details, design refinements, and the pitfalls of producing thousands of a thing. If you’re thinking of building a hardware kit or badge on this scale, you should really check it out and crib some of their production optimization tricks.

For instance, instead of labelling the parts “C2” or “R: 220 Ohms”, they used a simple color-coding scheme. This not only makes it easier for kids to assemble, but it also means that they didn’t have to stick 1,000 part labels on every component. Coupled with [overflo]’s Zerhacker, SMD parts in strips were cut to the right length and color-coded in one step, done by machine.

The coolest feature of the Blinkenrocket itself is the audio programming interface. It’s like in the bad old days of software stored on cassette tapes, but it’s a phenomenal interface for getting a simple animation out of a web app and straight into a piece of minimal hardware — just plug it into a laptop or cell phone’s audio out and press “play” in the browser. The original design tried to encode the data in the pulse-length of square waves, but this turned out to be very hardware dependent. The final design used frequency-shift keying. What’s old is new again.

Everything you could want to know about the design, its code, and even the website itself are up on the project’s GitHub page, so go check it out. If you’d like to arrange a Blinkenrocket workshop yourself, shoot [muzy] or [overflo] an e-mail. Full disclosure: [overflo] gave us a kit, the “hard-mode” SMD one with ~~0805~~ 1206 parts, and it was fun to assemble and program.

Before…

After

These Engineering Ed Projects Are Our Kind Of Hacks

May 25, 2017 by Mike Szczys 23 Comments

Highly polished all-in-one gear for teaching STEM is one way to approach the problem. But for some, they can be intimidating and the up-front expenditure can be a barrier to just trying something before you’re certain you want to commit. [Miranda] is taking a different approach with the aim of making engineering education possible with junk you have around the house. The point is to play around with engineering concepts with having to worry about doing it exactly right, or with exactly the right materials. You know… hacking!

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The Heathkit Mystery

December 22, 2014 by Brian Benchoff 58 Comments

Heathkit is a company that requires no introduction. From the mid-40s until the 90s, Heathkit was the brand for electronic kits ranging from test equipment, HiFis, amateur radio equipment, computers, to freakin’ robots. Their departure was a tragic loss for generations of engineers, electronic tinkerers and hobbyists who grew up with these excellent and useful kits.

Although Heathkit is dead, 2013 brought an announcement that Heathkit was back in the biz. A Facebook page was launched, a Reddit AMA was held, and the news was that Heathkit would rise from the dead in the first half of 2014. It’s now Christmas, 2014, and there’s no sign of Heathkit anywhere. Adafruit has been keeping a watchful eye on the on the (lack of) developments, and the only surprising thing to report is that there is nothing to report. There has been no new announcement, there are no new products, the “official” Heathkit website hasn’t been updated in a year, and no one knows what’s going on.

Adafruit has decided to dig into the matter, and while they’ve come up with a few items of note, there’s not much to report. A trademark for ‘HEATHKIT’ was filed October 27, 2014 – two months ago. An email was sent to the attorney of record and there has been no response.

This trademark was granted to Heathkit Company, Inc., incorporated in Delaware. Searching for any companies in Delaware using the Heathkit name returns exactly two results: Heathkit Company, Inc., and Heathkit Holdings, Inc.. Adafruit is probably going to pay the $20 to the Delaware Department of State to get the detailed information that includes Heathkit’s tax assessment and tax filing history.

The last bit of information comes from a whois on the heathkit.com domain. The relevant contacts have been emailed, and there are no further details. The Heathkit virtual museum was contacted for information, as was the news editor for ARRL.org. Nobody knows anything, or at least nobody is telling anybody anything.

To date, the only physical evidence of Heathkit’s rebirth is a geocache that was left at Brooklyn Bridge Park, announced during the Reddit AMA. This geocache was recovered by reddit user IFoundTheHeathKit, a throwaway account that had no posts before or since finding the cache. We have no idea what was in that geocache, what the ‘secret passphrase’ or set of instructions was, or if anything ever came of the promise to send one of the first new kits.

So there ‘ya go. A lot of words but no information. If you have any info, the Adafruit crew would like to have a word with you.

Update

The person who found the Heathkit geocache has been found:

The full comment referred to below is,

Hey, person who found the Heathkit geocache here. The secret passcode was an Einstein quote about radio vs wired communication (invisible cats), and they said they’d send me something in early 2014. Never had any communication except through FB, and they haven’t replied to any of my recent messages.

IFoundTheHeathKit might want to email Adafruit with a copy of all the emails.

Heathkit Is Back From The Dead

August 19, 2011 by Brian Benchoff 44 Comments

Although now it’s impossible for a DIY nut to build electronics for less money than a factory, this wasn’t always the case. For 45 years, Heathkit produced inexpensive kits for just about everything. Heathkit closed it’s kit business in 1992, but now they’re back. They’re starting out with a few DIY kits at first, namely an ultrasonic garage parking assistant and a wireless swimming pool monitor.

Heathkit is calling all builders to submit their ideas for future kits. While this comeback rings of some other outlets with a rich heritage, Heathkit is still remembered fondly; Barry Goldwater jetted out to the Heath HQ twice a year for kits. Not many people are that attached to Realistic and Optimus gear.

If you’re wondering about the kind of stuff Heathkit offered, feel free to check out the 1984 catalog that features computers with 128kB of RAM available for only $1899.00 (yes, a very competitive price)

Tip ‘o the hat to [Jeffrey Bail (N1BMX)].

Propeller-based Terminal

July 25, 2009 by Zach Banks 15 Comments

pocketerm

[Vince Briel] has created an embedded device based on the Parallax Propeller chip that acts as a serial terminal. It takes input from a standard PS/2 keyboard and outputs color VGA. It also has a second serial port to connect to a PC for debugging or programming. He is selling kits and has the schematics available. The board has a lot of hacking potential and it could easily be made into a video game or a Wikipedia browser.

[via RetroThing]