Back in 1966, a suitable toy for a geeky kid was a radio kit. You could find simple crystal radio sets or some more advanced ones. But some lucky kids got the Philips Electronic Engineer EE8 Kit on Christmas morning. [Anthony Francis-Jones] shows us how to build a 2-transistor AM radio from a Philips Electronic Engineer EE8 Kit.
According to [The Radar Room], the kit wasn’t just an AM radio. It had multiple circuits to make (one at a time, of course), ranging from a code oscillator to a “wetness detector.”
The kit came with a breadboard and some overlays for the various circuits, along with the required components. It relied on springs, friction, and gravity to hold most of the components to the breadboard. A little wire is used, but mostly the components are connected to each other with their leads and spring terminals.
CRT monitors: there’s nothing quite like ’em. But did you know that video projectors used to use CRTs? A trio of monochrome CRTs, in fact: one for each color; red, green, and blue. By their powers combined, these monsters were capable of fantastic resolution and image quality. Despite being nowhere near as bright as modern projectors, after being properly set up, [Technology Connections] says it’s still one of the best projected images he has seen outside of a movie theatre.
After a twenty-minute startup to reach thermal equilibrium, one can settle down with a chunky service manual for a ponderous calibration process involving an enormous remote control. The reward is a fantastic (albeit brightness-limited) picture.
Still, these projectors had drawbacks. They were limited in brightness, of course. But they were also complex, labor-intensive beasts to set up and calibrate. On the other hand, at least they were heavy.
[Technology Connections] gives us a good look at the Sony VPH-D50HT Mark II CRT Projector in its tri-lobed, liquid-cooled glory. This model is a relic by today’s standards, but natively supports 1080i via component video input and even preserves image quality and resolution by reshaping the image in each CRT to perform things like keystone correction, thus compensating for projection angle right at the source. Being an analog device, there is no hint of screen door effect or any other digital artifact. The picture is just there, limited only by the specks of phosphor on the face of each tube.
Converging and calibrating three separate projectors really was a nontrivial undertaking. There are some similarities to the big screen rear-projection TVs of the 90s and early 2000s (which were then displaced by plasma and flat-panel LCD displays). Unlike enclosed rear-projection TVs, the screen for projectors was not fixed, which meant all that calibration needed to be done on-site. A walkthrough of what that process was like — done with the help of many test patterns and a remote control that is as monstrous as it is confusing — starts at 15:35 in the video below.
Like rear-projection TVs, these projectors were displaced by newer technologies that were lighter, brighter, and easier to use. Still, just like other CRT displays, there was nothing quite like them. And if you find esoteric projector technologies intriguing, we have a feeling you will love the Eidophor.
USB power has become ubiquitous — everything from phones to laptops all use it — so why not your lab bench? This is what [EEEngineer4Ever] set out to do with the BenchVolt PD USB adjustable bench power supply. This is more than just a simple breakout for standard USB PD voltages, mind you; with adjustable voltages, SCPI support, and much more.
The case is made of laser-cut acrylic, mounted to an aluminum base, not only providing a weighted base but also helping with dissipating heat when pulling the 100 W this is capable of supplying. Inside the clear exterior, not only do you get to peek at all the circuitry but there is also a bright 1.9-inch TFT screen showing the voltage, current, and wattage of the various outputs. There is a knob that can adjust the variable voltage output and navigate through the menu. Control isn’t limited to the knob, mind you; there also is a Python desktop application to make it easy changing the settings and to open up the possibility to integrate its control alongside other automated test equipment.
There are five voltage outputs in this supply: three fixed ones—1.8 V, 2.5 V, and 3.3 V—and two adjustable ones: 0.5-5 V and 2.5-32 V. All five of these outputs are capable of up to 3 A. There are also a variety of waveforms that can be output, blurring the lines between power supply and function generator. While the BenchVolt PD will be open-sourced, [EEEngineer4Ever] will soon be releasing it over on CrowdSupply for those interested in one without building one themselves. We are big fans of USB PD gear, so be sure to check out some other USB PD projects we’ve featured.
With this new connectivity you can attach your One ROM to your computer with a USB cable and then in a matter of seconds upload new firmware from your Chrome (or Chromium) web browser. This new connectivity will supplement but not replace the existing serial wire connectivity because the serial wire connectivity enables certain advanced use cases not supported by the USB stack, such as reprogramming a ROM in-place as it’s being served. The new USB interface will probably suit most users who just want to use One ROM to manage the ROMs for their old kit and who don’t need the extra functionality.
Addressing the question as to why he didn’t have USB connectivity from the start [Piers] claimed it was because he didn’t like soldering the USB sockets! But given this is a service he can get from his board house that is no longer his problem! [Piers] said he picked Micro USB over USB-C because the former demands less circuit board real estate than the latter. Squeezing everything on to the board remains a challenge!
Our hacker [Pat Deegan] of Psychogenic Technologies shows us the entire process of designing an analog ASIC. An ASIC is of course an Application-Specific Integrated Circuit, which is basically just custom hardware. That’s right, “just” custom hardware.
In the video [Pat] takes you through using xschem (for schematic capture) and magic (for physical layout) to design a custom ADC. We learn that when it comes to hardware you have the choice of many different types of FETs, and not much else. Capacitors are expensive and to be avoided. Inductors are verboten. Getting specific values for things (such as resistors) is pretty much impossible so you generally just have to hope that things come out in relative proportions.
Some things are more fun when there are more folks involved, and enjoying time in the pool is one of those activities. Knowing this, [Bert Wagner] started thinking of ways to best coordinate pool activities with his kids and their neighborhood friends. Out of this came the Splashflag, an IoT device built from the ground up that provides fun pool parties and a great learning experience along the way.
The USB-powered Splashflag is housed in a 3D-printed case, with a simple 2×16 LCD mounted on the front to display the notification. There’s also a small servo mounted to the rear that raises a 3D-printed flag when the notification comes in—drawing your attention to it a bit more than just text alone would. Hidden on the back is also a reset button: a long press factory-resets the device to connect to a different Wi-Fi network, and a quick press clears the notification to return the device to its resting state.
Inside is an ESP32-S3 that drives the servo and display and connects to the Wi-Fi. The ESP32 is set up with a captive portal, easing the device’s connection to a wireless network. The ESP32, once connected, joins an MQTT broker hosted by [Bert Wagner], allowing easy sending of notifications via the web app he made to quickly and easily send out invitations.
Thanks, [Bert Wagner], for sharing the process of building this fun, unique IoT device—be sure to read all the details on his website or check out the code and design files available over on his GitHub. Check out some of our other IoT projects if this project has you interested in making your own.
When taking pictures of the night sky, any noise picked up by the sensor can obscure the desired result. One major cause of noise in CMOS sensors is heat—even small amounts can degrade the final image. To combat this, [Francisco C] of Deep SkyLab retrofitted an old Canon T1i DSLR with an external cooler to reduce thermal noise, which introduces random pixel variations that can hide faint stars.
While dedicated astrophotography cameras exist—and [Francisco C] even owns one—he wanted to see if he could improve an old DSLR by actively cooling its image sensor. He began with minor surgery, removing the rear panel and screen to expose the back of the sensor. Using a sub-$20 Peltier cooler (also called a TEC, or Thermoelectric Cooler), he placed its cold side against the sensor, creating a path to draw heat away.
Reassembling the camera required some compromises, such as leaving off the LCD screen due to space constraints. To prevent light leaks, [Francisco C] covered the exposed PCBs and viewfinder with tape. He then tested the setup, taking photos with the TEC disabled and enabled. Without cooling, the sensor started at 67°F but quickly rose to 88°F in sequential shots. With the TEC enabled, the sensor remained steady at 67°F across all shots, yielding a 2.8x improvement in the signal-to-noise ratio. Thanks to [Francisco C] for sharing this project! Check out his project page for more details, and explore our other astrophotography hacks for inspiration.
![[Anthony] holding the EE8 kit](https://hackaday.com/wp-content/uploads/2025/10/EE8-banner.jpg?w=600&h=450)
