Beautifully documented, modular, and completely open-source, this split flap display project by [JON-A-TRON] uses 3D printing, laser cutting and engraving, and parts anyone can find online to make a device that looks as sharp as it is brilliantly designed. Also, it appears to be a commentary on our modern culture since this beautifully engineered, highly complex device is limited to communicating via three-letter combos and cat pictures (or cat video, if you hold the button down!) As [JON-A-TRON] puts it, “Why use high-resolution, multi-functional devices when you can get back to your industrial revolution roots?” Video is embedded below.
Can you make a spectrometer for your home lab all from materials you have sitting around? We might not believe it from a less credible source, but this MIT course does indeed build a spectrometer from foam board using two razor blades as the silt cover and a writable CD as the diffraction grating. The coolest part is removing the metal backing of the CD.
Hackaday reader [gratian] tipped us off about the course available from MIT courseware called Nanomaker. It boils down some fairly complicated experiments to the kind one can do in the home lab without involving thousands of dollars of lab equipment. The whole point is to demystify what we think of as complicated devices and topics surrounding photovoltaics, organic photovoltaics, piezoelectricity and thermoelectricity.
Spectrometers are used to analyze the wavelengths of a light source. Now that you have a measurement tool in hand it’s time to build and experiment with some light sources of your own. Here you can see an LED that is the topic of one of the course labs.
If you have a bit of background in chemistry this is a good step-by-step guide for getting into these types of experiments at home. It reminds us of some of the really cool stuff [Jeri Ellsworth] was doing in her garage lab, like making her own EL panels.
As hackers and makers we are surrounded by accessible computing in an astonishing diversity. From tiny microcontrollers to multi-processor powerhouses, they have become the universal tool of our art. If you consider their architecture though you come to a surprising realisation. It is rare these days to interface directly to a microprocessor bus. Microcontrollers and systems-on-chip have all the functions that were once separate peripherals integrated into their packages, and though larger machines such as your laptop or server have their processor bus exposed you will never touch them as they head into your motherboard’s chipset.
A few decades ago this was definitely not the case. A typical 8-bit microprocessor of the 1970s had an 8-bit data bus, a 16-bit address bus, and a couple of request lines to indicate whether it wanted to talk to memory or an I/O port. Every peripheral you connected to it had to have some logic to decode its address and select it when you wanted to use it, and all shared the processor’s bus. This was how those of us whose first computers were the 8-bit machines of the late 1970s and early 1980s learned the craft of computer hardware, and in a world of Arduino and Raspberry Pi this now seems a lost art.
The subject of today’s review then provides a rare opportunity for the curious hardware hacker to get to grips with a traditional microprocessor bus. The RC2014 is a modular 8-bit computer in which daughter cards containing RAM, ROM, serial interface, clock, and Z80 processor are ranged on a backplane board, allowing complete understanding of and access to the workings of each part of the system. It comes with a ROM BASIC, and interfaces to a host computer through a serial port. There is also an ever-expanding range of further peripheral cards, including ones for digital I/O, LED matrixes, blinkenlights, a Raspberry Pi Zero for use as a VDU, and a small keyboard.
[Brian Leach] of the South East London Meccano Club has put an impressive amount of ingenuity into making his pinball machine almost entirely out of Meccano parts. He started in 2013 and we saw an earlier version of the table back in 2014, but it has finally been completed. It has all the trappings of proper pinball: score counter, score multiplier with timeout, standing targets, kickouts, pot bumpers, drop targets, and (of course) flippers and plunger.
The video (embedded below) is very well produced with excellent closeups of the different mechanisms as [Brian] gives a concise tour of the machine. Some elements are relatively straightforward, others required workarounds to get the right operation, but it’s all beautifully done. For example, look at the score counter below. Meccano electromagnets are too weak to drive the numbers directly, so a motor turns all numbers continuously with a friction drive and electromagnets are used to stop the rotation at specific points. Reset consists of letting the numbers spin freely to 9999 then doing a last little push for a clean rollover to zero.
When [Douglas Welcome] found a disposed Kalart Craig 16 mm Projecto-Editor on the curb, he knew it was destined for retro-greatness. This vintage looking device was once used to view and cut 16 mm film strips, and still in mint condition, it was just too cool to pass up. With help of a similarly historic Raspberry Pi 1 Model B, and a little LCD screen, [Douglas] now turned the little box into an awesome retro arcade game console
The Apollo program is a constant reminder that we just don’t need so much to get the job done. Sure it’s easier with today’s tools, but hard work can do it too. [Bill Hammack] elaborates on one such piece of engineering: The Alignment Optical Telescope.
The telescope was used to find the position of the Lunar Module in space so that its guidance computer could do the calculations needed to bring the module home. It does this using techniques that we’ve been using for centuries on land and still use today in space; although now it’s done with computer vision. It was used to align the craft to the stars. NASA used stars as the fixed reference points for the coordinate system used to locate objects in space. But how was this accomplished with great precision?
The alignment optical telescope did this by measuring two unknowns needed by the guidance computer. The astronaut would find the first value by pointing the telescope in the general area necessary to establish a reading, then rotate the first reticle (a horizontal line) on the telescope until it touched the correct star. A ring assembly was then adjusted, moving an Archimedes spiral etched onto the viewfinder. When the spiral touches the star you can read the second value, established by how far the ring has been rotated.
If you’ve ever seen the Lunar Module in person, your first impression might be to giggle a bit at how crude it is. The truth is that much of that crudeness was hard fought to achieve. They needed the simplest, lightest, and most reliable assembly the world had ever constructed. As [Bill Hammack] states at the end of the video, breaking the complicated tool usually used into two simple dials is an amazing engineering achievement.
[Scott Baker] wanted to take on a new retrocomputing project. He decided to build an RC2104. Lucky for us, he documented everything along the way. In addition to the main board, [Scott] built bus monitoring and debugging tools, a front panel, a real time clock, an analog to digital converter, and a speech synthesizer.
You can follow along in the 8-part post that includes videos. He started with the basic kit:
- CPU – The Z80
- ROM – 27C512 64 KB ROM, selectable in 8KB banks
- RAM – 62256 32 KB RAM
- Clock – 7.3728 Mhz crystal that drives a 74HC04 hex inverter (for the CPU and the UART)
- Serial I/O – MC68B50 UART
In addition, he picked up a digital I/O board.