Internet radio

Engineering in April: ClockClock, Elektor’s Internet Radio, and More

Want to know more about some of the projects from previous April editions of Elektor? Here we highlight some interesting articles and projects dating back to 1975. You’re sure to find them particularly inspiring: the ClockClock, Elektor’s Internet Radio, the E-Meter, and more.

Want to know more about some of the projects from previous April editions of Elektor? Below we highlight some interesting articles and projects dating back to 1975. We could have listed dozens more, but we think you will find them particularly inspiring. After reaching the workbench, also tell us about your engineering projects.

The ClockClock Project (April 2021)

Elektor has been publishing innovative clock projects for a long time. In 2021, we published a project that won over our engineering community. ClockClock’s design was simply a clock made of clocks. But the design process wasn’t that simple. Designer Justin Rajewski used many analog-style clocks to form the hour numerals.

The frame of the ClockClock was constructed from two maple planks.

The project included an FPGA and 48 stepper motors. “In addition to showing the massive amount of FPGA IOs that are capable of, this project uses the Qwiic connector on the FPGA in a semi-unconventional way,” he explained. “The FPGA in this project acts as a peripheral rather than a controller. The Arduino is the controller and sends all commands to the FPGA. I actually think this will be a useful paradigm for many projects.”

Inside the ClockClock - Engineering in April
The 102 wires going into the FPGA don’t really matter which pins they connect to.

Motion detection camera trigger using Arduino (April 2014)

Want to take photos using motion detection? You can easily make your own motion detection camera trigger using an Arduino, a capacitor, some resistors, and some software.

Motion detection camera trigger using Arduino
The entire circuit is housed in a splash-proof case

“It turned out that connecting the PIR board to an analog input of the Arduino was more convenient than using a digital input,” explained Rolf Blijleven. “A digital output from the Arduino is used for the IR LED with a series resistor, which is used to operate the camera. The three AA batteries for the nightlight also serve as a power supply for the Arduino.”

Diagram of motion detection camera trigger
The complete circuit with Arduino, IR LED and PIR board (formerly pilot light).

Any movement within a few feet of the PIR sensor will trigger the camera. It also works through glass, so you can keep your camera inside and place the sensor/remote outside.

Elektor Internet Radio (April 2008)

Back in the day, you had to modulate audio signals onto an RF carrier so they could be received and demodulated to produce something audible. Today, audio signals are compressed and placed in IP packets which are streamed. This means you access thousands of internet radio programs by receiving, buffering and unpacking the packages. Elektor Internet Radio makes it easy for you.

Elektor Internet Radio
The layout of the components (left) and the fully assembled prototype (right).

“Before you can start listening to the radio, you must remove the test firmware from the EIR and install the radio firmware,” explained designers Harald Kipp and Dr. Thomas Scherer. “To enable new firmware to be loaded, first connect pin 34 and 36 of connector K3 with a jumper, then press Reset, and finally remove the jumper. After that, the EIR will reboot with the bootloader, and you can use SAM-BA to download the radio firmware Now connect the EIR to your local network via the Ethernet port (using a multi-port internet hub, switch or router ) and connect the audio output to headphones or an amplifier.”

Soil Moisture Tester (April 2001)

Do you have a knack for letting your plants wither and die? If so, consider designing a soil moisture tester. Sure, you can buy from Amazon, but wouldn’t it be more fun to build one from scratch? In April 2001, Elektor presented a fairly simple design.

Diagram of soil moisture.  Engineering in April
The complete circuit is only slightly more complex than the block diagram.

Once ready, you stick two electrodes into the ground and the moisture level appears on an LED display. Green LEDs indicate wet soil, yellow LEDs let you know it’s getting a little dry, and red LEDs let you know that immediate action is needed.

“The electrodes are made of two lengths of rigid, insulated copper wire, approximately 10cm long and 1mm thick. 4cm of insulation is stripped from the ends, which are then tinned. This is to avoid copper wire from oxidizing. The connection between the electrodes and the circuit could be made with two lengths of flexible stranded wire.”

Electronic meter: check the radiation of your display screen (April 1998)

Wondering whether or not your electronic components are bad for your health is nothing new. Engineers have been thinking about these things for years. In fact, in April 1998, Elektor introduced the innovative E-Meter to monitor radiation emitted from display screens.

The prototype of the electrometer

Designer H. Bonekamp explains: “The most demanding part of the circuit is the sensor, a DIY air capacitor. This is made from two 30×30 cm aluminum sheets… The sheets are fixed between them by four nylon screws, nuts and 10 mm long spacers: one at each corner. Nylon screws, nuts and spacers are used because they do not affect the capacitance, which is about 80 pF.”

Design of a dimmer for halogen lamps (April 1991)

Back in 1991, engineering enthusiasts didn’t have smartphones to remotely control the lights in their homes and offices. But they had other solutions, as described in this article. The dimmer is based on the concept that each light in a two-wire system can be controlled remotely without any effect on the other lights in the system. A handheld infrared remote control offers four functions: light on, light off, light brighter and dimmer.

Halogen dimmer project
Cireuil’s schematic of the remote control transmitter.

The remote control transmitter is based on Plessey’s Type MV500 JC. “In addition to a keyboard, an oscillator and a driver for the infrared diodes, this integrated circuit contains everything necessary for a 32-channel infrared transmitter. Since the receiver board must necessarily remain small ( approximately 50×40 mm), the current transmitter is limited to six channels.”

Light Powered Radio (April 1985)

Elektor readers and engineers were one step ahead when it came to solar power. For example, in April 1985, we introduced a compact radio powered by solar cells. Check out the light-powered radio design.

Radio powered by light.  Engineering in April
Save energy with light.

“To keep the design simple and easy to build, we opted for a straight mid-wave receiver as it lends itself perfectly to our needs. The circuit is based on a Ferranti ZN416. This IC is a welcome addition to the range which includes the popular ZN414 and ZN415 (descriptions of these appeared in the May 1982 and November 1983 issues of Elektor.) The ZN416 contains a full-featured AM receiver with enough audio output to drive headphones directly. It covers the frequency range of 150 kHz…3 MHz which includes the medium and long wave broadcast bands.

Fido (April 1975)

Fido was an electronic game introduced in 1975. How did you play? An unfortunate dog was called by four masters at once. The “Fido come” command was generated with a push button. Fido would jump in the direction of a push. “After a successful command to Fido, the potential Fido owner who gave the command has no more say for a while. Then other players can continue with Fido. If one of the players succeeds in entering Fido in his kennel, the game is decided.”

Artist’s impression of Fido (left) and block diagram (right).

More engineering to come!

Join us next month when we highlight more Classic Elektor engineering articles, projects and tutorials. And don’t forget to share your thoughts in the comments section below. The engineering continues!