Why Not Expose Your PCBs Through An LCD?

Most people who have dabbled in the world of electronic construction will be familiar in some form with the process of producing a printed circuit board by exposing a UV sensitive coating through a transparent mask, before moving on to etching. Older readers will have created their masks by hand with crêpe paper tape on acetate, while perhaps younger ones started by laser-printing from their CAD package.

How about a refinement of the process, one which does away with the acetate mask entirely? [Ionel Ciobanuc] may have the answer, in the form of an exposure through an LCD screen. The video below the break shows how it’s done, starting with a (probably a bit too lengthy) sequence on applying the photo-resist coating to the board, and then sitting LCD on top of UV lamp with the board positioned at the top of the pile.

It’s an interesting demonstration, and one that certainly removes a step in the process of PCB creation as it brings the pattern direct from computer to board without an intermediate. Whether or not it’s worth the expenditure on an LCD is up to you, after all a sheet of acetate is pretty cheap and if you already have a laser printer you’re good to go. We’re curious to know whether or not any plastic components in the LCD itself might be damaged by long-term exposure to intense UV light.

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Hacked Headset Brings VR to the Commodore 64

The venerable Commodore 64 got a lot of people started in computers, and a hard core of aficionados keeps the platform very much alive to this day. But a C64 just doesn’t have the horsepower to do anything more than some retro 8-bit graphics games, right?

Not if [jim_64] has anything to say about it. He’s created a pair of virtual-reality goggles for the C64, and the results are pretty neat. Calling them VR is a bit of a stretch, since that would imply the headset is capable of sensing the wearer’s movements, which it’s not. With just a small LCD screen tucked into the slot normally occupied by a smartphone in the cheap VR goggles [jim64] used as a foundation for his build, this is really more of a 3D wearable display — so far. The display brings 3D-graphics to the C64, at least for the “Street Defender” game that [jim64] authored, a demo of which can be seen below. We’ll bet position sensing could be built into the goggles to control the game too. Even then it won’t be quite the immersive (and oft-times nauseating) experience that VR has become, but for a 35-year old platform, it’s not too shabby.

Looking for more C64 love? We’ve got a million of ’em — case mods, C64 laptops, tablets, even CPU upgrades.

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Digitool Helps Debugging

Logic analyzers used to be large boxes full of high-speed logic and a display monitor. Today, they are more likely to be a small box with a USB port that feeds data to a PC application. [Juan Antonio Rubia Mena] wanted something more self-contained, so he built Digitool. Built around a PIC18F2525, the device can measure frequency up to 10 MHz and inject square waves up to 1 MHz into the circuit under test. Oh yeah. It also has a simple four-channel logic analyzer that displays on a tiny LCD.

The 500,000 sample per second rate and the 1024 sample buffer isn’t going to put any logic analyzer vendors out of business, but it is still enough to help you figure out why that SPI or I2C logic is messed up. It looks like a fun project that could have some usefulness.

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Adding Character To The C64

The venerable Commodore 64, is there anything it can’t do? Like many 1980s computer platforms, direct access to memory and peripherals makes hacking easy and fun. In particular, you’ll find serial & parallel ports are ripe for experimentation, but the Commodore has its expansion/cartridge port, too, and [Frank Buss] decided to hook it up to a two-line character LCD.

Using the expansion port for this duty is a little unconventional. Unlike the parallel port, the expansion port doesn’t have a stable output, as such. The port contains the data lines of the 6510 CPU and thus updates whenever RAM is read or written to, rather then updating in a controlled fashion like a parallel port does. However, [Frank] found a way around this – the IO1 and IO2 lines go low when certain areas of memory are written to. By combining these with latch circuitry, it’s possible to gain up to 16 parallel output lines – more than enough to drive a simple HD44780 display! It’s a testament to the flexibility of 74-series logic.
It’s all built on a C64 cartridge proto-board of [Frank]’s own design, and effort was made to ensure the LCD works with BASIC for easy experimentation. It’s a tidy mod that could easily be built into a nice enclosure and perhaps used as the basis for an 8-bit automation project. Someone’s gotta top that Amiga 2000 running the school district HVAC, after all!

Hackaday Prize Entry: DIY LCD based SLA 3D Printer

Resin-based SLA 3D printers are seen more and more nowadays but remain relatively uncommon. This Low Cost, Open Source, LCD based SLA 3D Printer design by [Dylan Reynolds] is a concept that aims to make DIY SLA 3D printing more accessible. The idea is to use hardware and manufacturing methods that are more readily available to hobbyists to create a reliable and consistent DIY platform.

[Dylan]’s goal isn’t really to compete with any of the hobbyist or prosumer options on the market; it’s more a test bed for himself and others, to show that a low-cost design that takes full advantage of modern hardware like the Raspberry Pi can be made. The result would be a hackable platform to let people more easily develop, experiment, or simply tamper with whatever part or parts they wish.

The Other Kind of Phone Hacking

While it’s true that your parts bin might have a few parts harvested from outdated devices of recent vintage, there’s not much to glean anymore aside from wall warts. But the 3×48-character LCD from [Kerry Wong]’s old Uniden cordless landline phone was tempting enough for him to attempt a teardown and reverse engineering, and the results were instructive.

No data sheet? No problem. [Kerry] couldn’t find anything out about the nicely backlit display, so onto the logic analyzer it went. With only eight leads from the main board to the display module, it wasn’t likely to be a parallel protocol, and the video below shows that to be the case. A little fiddling with the parameters showed the protocol was Serial Peripheral Interface, but as with other standards that aren’t exactly standardized, [Kerry] was left with enough ambiguity to make the analysis interesting. Despite a mysterious header of 39 characters, he was able in the end to drive the LCD with an Arduino, and given that these phones were usually sold as a bundle with a base and several handsets, he ought to have a nice collection of displays for the parts bin.

With how prevalent this protocol has gotten, [Kerry]’s post makes us want to get up to speed on the basics of SPI. And to buy a logic analyzer too.

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FPGA Rescues Scope From The Dumpster

I’m always on the lookout for a quality addition to my lab that would respect my strict budget. Recently, I’ve found myself pushing the Hertz barrier with every other project I do and hence desperately wanted a high bandwidth scope. Unfortunately, only recently have 70 MHz to 100 MHz become really affordable, whilst a new quad channel oscilloscope in the 500 MHz to 1 GHz range still costs a fortune to acquire. My only option was to find an absolute miracle in the form of an old high bandwidth scope.

It seemed the Gods of Hand Me Down electronics were smiling upon me when I found this dumpster destined HP 54542C. It appeared to be in fairy good shape and was the Top Dog in its day. But something had to be broken right? Sure enough, the screen was clearly faulty and illegible. Want to know how I fixed it? Four letters: FPGA.

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