A Revolutionary Input Device, 30 Years Too Late

Way before you kids had touch screens and mice, we had to walk uphill both ways to tell a computer where we were pointing at on the screen. I speak, of course, of light pens. When these photodiodes in a pen were pointed at a CRT, the display driver would tell the computer where the pen was pointing. It’s a pretty incredible video hack today, and these things were around in the 1970s. You could, of course, use a light pen with most of the old 8-bit home computers, including the Commodore 64.

[Jan] has a soft spot for the light pen on the C64. So much so he made a new input device using this tech. It’s great, and if this existed in 1985, all the cool kids would have known about it.

The build is called the LightHammer. It’s a light pen, inside the head of a plastic hammer, with a few springs, nuts, and washers to tell the computer to read the light pen input. The light pen itself is just a photodiode with a few transistors; it was a simple circuit in the 80s, and it’s a simple circuit today.

A new input device isn’t worth anything without an app to show off the tech, and [Jan] is about three steps ahead of us here. He wrote a game for this LightHammer – a digital version of Whac-A-Mole and Simon. They’re exactly what you think they are: the classic ‘repeat the computer’ and ‘murder rodents’ games.

If that’s not enough, [Jan] also built an arcade cabinet for his C64 setup, with the monitor, joysticks, a 1541, and a TV mounted in a cabinet that would look great in a bar. You can check out a video of that and the games using the LightHammer below.

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Commodore 64 Mods Make A Mobile Computer

Some Commodore C64 owners and enthusiasts keep tinkering with their precious units, adding upgrades all the time. [wpqrek]’s latest upgrade to his C64 makes it totally portable – he added DC-DC converters to allow it to run off external battery sources.

He installed two separate DC-DC converters – one for 5V and another for 9V inside the enclosure. He opted for these high-efficiency converters because he planned to use batteries to power the device and wanted to maximize the juice he was extracting. He wired up a barrel jack socket to accept a 12V input, and another XT60 socket where he could attach a LiPo battery. A common 2200mAh RC battery is enough to power his C64 for 1.5 hours. To ensure the LiPo battery doesn’t get fully discharged, he’s added a simple buzzer circuit that starts beeping at around 3.3V.

How does just adding an external battery help make it portable? Well, he’s already added a small LCD display and a couple of other mods, that we featured in an earlier post. These earlier mod’s didn’t make the unit truly portable. Adding the latest hack does. Check out the video after the break.

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Hackaday Links: April 26, 2015

In case you haven’t heard, we’re giving away a trip to space. We have $50,000 to promote giving away a trip to space too, and this week we’re giving away some OSH Park gift cards. If you have a project that’s held together with hot glue on a 40-year-old piece of perf board, add a project log describing how you need some free PCBs.

A few months ago, some guy in Texas found the original molds for the Commodore 64C, the Plus/4 and the 128. That discovery turned into one of the best examples of what Kickstarter can do. Now, new keycaps are being manufactured with an Indiegogo campaign. If you’re waiting on your C64c case to be pressed out of a mold, this is not the time to think about the sunk cost fallacy. They’re not Cherry MX compatible, but they will work with just about every version of the C64. Not bad for under €20.

The UK has a fabulously rich history of ancient melee weapons, ranging from the flail to the mace and a bunch of odd bladed weapons used by the Scots. This tradition was passed down to the UK mains plug, the single most painful plug to step on. Apple just released a USB charger with a folding UK mains plug and [oliver] did a teardown on it.

For St. George’s Day in Catalonia, there’s a tradition of giving roses to women, and books to men. [Nixieguy] has all the books he could want, and would prefer to receive a rose. Bucking tradition, he made himself a rose from a punch card. It’s the closest he’s going to get to ‘@}-\—’. A few years ago, he carved a rose out of a 10mm LED.

Finally, a decent tutorial on how to grow your own SMD components.

Need to take apart a cellphone? Use acetone! Need the phone to work after you take it apart? Ummmm….

The Dayton Hamvention is just three weeks away! Yes, the same weekend as the Bay Area Maker’s Faire, which means most of the Hackaday crew will be elsewhere, but I hear [Chris Gammell] will be there putting Parts.io stickers on everything. By the way, I’m looking for a Tek PM203 Personality Module for a 68000 64-pin PDIP.

A VU-meter indicator for a Commodore 1530 Datasette

For present-day owners of vintage Commodore computers, keeping data and programs safe and backed up is top priority. Disk drive storage was more common in the US, whereas in Europe, the audio cassette was the preferred medium of storage.

The Datasette device was what allowed interfacing the cassettes to the computer. Tape head alignment was critical to successfully writing and reading data to the cassette. Some models of the Datasette came with a small hole above the keys, to allow access to the adjustment screw of the tape head azimuth position. Tweaking this while looking at a signal meter could help you improve the signal from a bad cassette and prevent load errors. [Jani] tried a commercial solution called “Load-IT” which had a LED bargraph, but it couldn’t help much dealing with tapes with very bad signals. So he built a signal strength meter for his Datasette. He calls it the VU-sette since it uses an analog style meter quite similar to the VU-meters found in many audio equipment.

The hardware is simple and uses commonly available parts. The analog meter is extracted from a Battery Checker sourced from eBay. An op-amp drives the analog meter, and another transistor drives a separate speaker. This can be used to listen in on the cassette, if the speaker is enabled via a push button. [Jani] first breadboarded and tested the circuit before ordering out prototype boards.

To test performance, [Jani] used FinalTAP, a tool for examining, cleaning and restoring digitized data cassette tapes (TAP files) for the Commodore 64 computer. The “LOAD-IT” version worked well with tapes that were in fairly good condition. But his VU-sette version allowed him to adjust the head more precisely and get out a much better read from bad tapes. While on the subject, check out this nice 7-segment bubble LED digital counter for the 1530.

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Hackaday Retro Edition: A New Commodore 64 Case

Some time in the 80s, the plastic injection molds for the Commodore 64C, the Commodore 128, and the Plus/4 were shipped from somewhere in Asia to the great Commodore Mother Brain in West Chester, Pennsylvania. These molds had already produced a million or two cases, but there were some issues with production – too much waste, or something like that. A mechanical engineer took a look at the molds, sent out some recommendations, and moved the 2500 pound molds to a corner of the building.

For some time after a gray day in April, 1994 these molds sat in a West Chester, Pennsylvania warehouse until they were sold off. They made their way to a plastics manufacturer around Dallas, Texas where they sat for twenty years. All things must pass, sometimes several times, and this plastics manufacturer closed down, contacted an auctioneer, and began to sell off some of their equipment.

The hero of our story, [Dallas Moore], owns a small business, buying and selling everything from Barbie dolls to antiques. He found an ad for an auction at a plastics manufacturing plant in the newspaper, and figuring he could find something interesting, headed out to the auction preview.

The auctioneer at this liquidation sale asked [Dallas] what he did, and mentioned there was something pretty cool tucked away in a warehouse full of hardened steel molds. Something about molds for old computers. These were the molds for the Commodore 64C, Commodore 128, and the Commodore Plus/4. A literal crucible of computing history, stacked on a pallet and up for sale.

The auctioneer said one of his friends was interested in the molds, and thought they would make a neat coffee table. Something about this struck [Dallas] the wrong way and for the entire drive home he thought about someone taking history and turning it in to a piece of furniture. He decided to buy these molds and lugged the three 2500 pound pieces of hardened steel to his shop. Not wanting to let a good piece of history go to waste, he contacted another plastics manufacturer, planned a run of a thousand or so Commodore 64C cases in red, white, and blue. [Dallas] is funding the whole production run through Kickstarter.

To me, this is one of the greatest retrocomputing successes in recent memory. There will always be someone putting SD cards in old computers, getting them on the Internet (and especially pointed towards our retro edition), and cloning complete systems in FPGAs. This, though, is a clear example of someone recognizing the historical importance of several thousand pounds of steel, realizing there’s a market out there, and doing the leg work to remanufacture these pieces of history.

I put in my $45 for a red one, and I tipped off [Bil Herd], designer of the C128 and Plus/4, to this Kickstarter. He’s been talking with [Dallas], there I’m sure he’ll chime in on the comments with some retellings of Commodore battle stories.

If it arrives in time, I’ll be bringing my limited-edition red 64C case to the Vintage Computer Festival in Wall, NJ April 17-19. That’s a plug for the event. If you’re in the area, you should come.

EDIT: [Dallas] has a different story of where the molds came from.

A Raspberry Pi SID Player

Of all the vintage chiptune machines out there, the Commodore 64 is the most famous. Even 30 years later, there are still massive gatherings dedicated to eeking out the last cycle of processing power and graphics capability from the CPU and the infamous synth-on-a-chip, the SID. [Bob] wanted to build a SID jukebox. A C64 is capable of the job, but if you want to have every SID composition on an SD card and connect that to a network, a Raspberry Pi is the way to go.

The SID chip, in its 6581 or 8580 versions, is controlled directly by poking registers on the chip through the address and data busses. This means a lot of pins, too many for the original Raspi expansion header. That’s not a problem that can’t be solved with a few shift registers, though. The rest of the circuit is an LM386 audio amplifier, an LCD that displays the current song, and a can crystal oscillator for the SID.

Right now everything is wired up on a breadboard, but making this a Raspberry Pi hat would be a rather simple proposition. It’s only a matter of finding a SID with working filters, and if you can manage that, it’s a pretty easy build to replicate. Video below.

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Dual Porting a C64 Flash Cart

The old cartridges for the Commodore 64 use EEPROMs to store their data, and the newer Flash carts use either a Flash chip or an SD card to put a whole bunch of games in a small plastic brick. [Stian] and [Runar] thought that wasn’t good enough – they wanted to program cartridges in real time, the ability to reboot the C64 without ever touching it, and a device for coding and testing. What they came up with is the latest advance in Commodore cartridge technology.

The device presents 8k of memory to the C64, but it doesn’t do this with Flash or an EEPROM. Instead, [Stian] and [Runar] are using a dual-port static RAM, specifically one from the IDT7005 series. This chip has two data busses, two address busses, and /CE, /OE, and R/W lines for either side of the chip, allowing other digital circuits to be connected to one small section of the C64’s memory.

Also in the cart is an ATmega16 running V-USB to handle the PC communications. It takes about 1 to 1.5 seconds to transfer an entire 8k over to the cartridge, but this chip can read and write the RAM along with the C64 simultaneously.

If you want a box that will give you the ability to put ever game in existence on a single cartridge, this isn’t the one. However, if you want to write some C64 games and do some live debugging, this is the one for you. The Eagle files are available, and there’s a video demo below.

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