App note: Integrated supercapacitor charger

Application circuit of supercapacitor ENYCAP(TM) power management from Vishay. Link here (PDF)

The MAL219699001E3 demonstration circuit is a fully transparent power management solution with a regulated 2 W output and integrated power backup. It provides a DC/DC regulator with a wide power input range from 4.0 V to 20 V and adjustable regulated output between 3.3 V and 5.0 V.

Cloning a 6502 Apple-1 in just 930 logic gates

Turning 930 logic gates into a working 6502 Apple-1 clone:

Two years ago, the Gigatron arrived on the retrocomputing scene. It needs just 930 logic gates (packed into 33 standard 7400-series ICs) to create a computer that beat ‘complex’ 1980s home computers like the VIC-20 in terms of both CPU power and graphics. Without microprocessor, graphics, or even an ALU chip, the machine can do this sort of thing with effectively only half of the transistor count inside the 6502 CPU alone. Quite a feat, but more importantly, the hardware is simple enough so that anyone can figure out how it works. Read about it in my previous post

See the full details on Obsolescence Guaranteed blog.

Making an unusual and beautiful single-digit clock

A DIY single-digit clock using Arduino Nano, RTC and 3D printed 7-segment digit:

Generally at we post original projects we dream up ourselves. Today’s post is a little different. We’re going to describe how we constructed Mirko Pavleski’s single-digit clock. We made it because it’s a fun project, wonderfully impressive to look at, and a great design. Not only is the idea original, Mirko’s stl files for 3D printing are excellent, and his coding for the Arduino is very, very, sophisticated.

See the full details at

Check out the video after the break.

Continue reading “Making an unusual and beautiful single-digit clock”

Reverse-engineering the audio amplifier chip in the Nintendo Game Boy Color

Ken has written an article on reverse engineering the audio amplifier chip in the Nintendo Game Boy Color:

The Nintendo Game Boy Color is a handheld game console that was released in 1998. It uses an audio amplifier chip to drive the internal speaker or stereo headphones. In this blog post, I reverse-engineer this chip from die photos and explain how it works.1 It’s essentially three power op-amps with some interesting circuitry inside.

More details on Ken Shirriff’s blog.

Broadlink smart bulb conversion to open source

VikTak writes:

Many of the current bulbs on the market are based on the same chip, the ESP8266. These bulbs are very easy to “hack” and replace the firmware in them with the likes of my ActoSenso or the more widely known and used Tasmota. However, not all bulbs use the same chip. One of my bulbs turned out to have a Broadlink BL3336T-P WiFi module in it. This chip is not open source and not well documented (like the ESP8266 family), so anyone trying to write new firmware for it must first figure out what exactly the chip does and how exactly it does it. This is not an impossible task – some have managed to make great progress on figuring out the inner workings of it, but it is a slow, hit and miss process.
In this article I will show a different approach: I replaced the WiFi chip along with its PCB and other parts that drive the LEDs and designed a new, drop-in replacement based on the ESP8266 chip.

See the full post at

#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.


NRI G-13.mft parallel coin acceptor to Serial adapter

David has been working on an ATmega based USB serial adapter for the NRI G-13.mft coin validator:

The NRI G-13.mft by Crane is a versatile and high secure coin validator. It can be programmed using the propretary WinEMP software and PC interface, or event it has some DIP Switch that can be used to program the device. Unluckily it does not come with a UART interface. But it features a “machine tester” I/O interface we can use to track the inserted coins.

See the full post on Davide Gironi’s blog.

Check out the video after the break.

Continue reading “NRI G-13.mft parallel coin acceptor to Serial adapter”

App note: Design of a 100W active clamp forward DC-DC converter for telecom systems using the NCP1562

Another DC-DC converter design using ON Semiconductor’s NCP1562 PWM Controller. Link here (PDF)

The NCP1562 PWM controller contains all the features and flexibility needed to implement an active clamp forward dc−dc converter. This IC operates from an input supply up to 150 V, thus covering the input voltages usually found in telecom, datacom and 42 V automotive systems. One can also note that the NCP1562 can be used in mains related applications (e.g. desktop, server, flat TVs) as it can be supplied by an auxiliary power supply

App note: Power-handling capabilities of inductors

App note from Coilcraft on how to calculate the power dissipation of an inductor. Link here (PDF)

Inductors are not typically rated by power, however an approximation of the power-handling capability of an air core or ceramic core chip inductor can be estimated using the data sheet specifications for current and resistance.

Commodore 64 for STM32F429 Discovery board

Dave built a Commodore 64 emulator for STM32F429 Discovery board:

Yeah, the LCD is tiny at 2.4″, and the emulation runs about 15% slower than an NTSC C64. But it’s running on a small embedded board that’s available for under $30 US (DigiKey, Mouser, …) including mounted LCD display and USB OTG jack. Just add keyboard, OTG USB adapter, and power supply.
This is a port of my portable C64/6502 emulator for terminal console, which was a port of my Commodore/6502 emulator for Windows Console. But this time, I dropped the console part, and went for real video (LCD) and USB keyboard support. Hello PETSCII!

See the full post on Tech with Dave blog.

Face tracking robot with an ESP32-CAM

An ESP32-CAM face follow bot @

I wanted to add face tracking to the robot so it could follow a person around the house. I added an ESP32-CAM camera module, mounted with 3d printed parts and connected via cables to serial on the Arduino Nano on the Robot.

Check out the video after the break.

Continue reading “Face tracking robot with an ESP32-CAM”

Tutorial: Rename, copy or clone Eclipse projects with MCUXpresso

Erich writes:

Especially in a lab or classroom environment it is convenient to start with a template project, and then explore different ways to shape the project for different needs. As for any IDE of this world, this requires an understanding of the inner workings to get it right. So in this article I show how to copy, clone or rename properly an Eclipse ‘template’ project in the MCUXpresso IDE.

More details at

DIY Arduino RC receiver for RC models and Arduino projects

Dejan @ shows how to make an Arduino based RC receiver:

Now these two devices can easily communicate and we can use them for controlling many things wirelessly. I will explain how everything works through few examples. In the first example we will use this Arduino RC receiver to control a simple car consisting of two DC motors. In the second example I will show you how to control brushless motors and servos, which are common components found in many commercial RC planes, boats, cars and so on. If we know how to control them, we can easily modify and control many RC models with our own custom-build Arduino transmitter.
As a third example I will show you how I modified and used this Arduino based RC system to control a commercial RC car.

More details on How To Mechatronics Project page.

Check out the video after the break.

Continue reading “DIY Arduino RC receiver for RC models and Arduino projects”

App note: Driving multiple loads with 32 kHz Nano-Power MEMS oscillators

Accomodating multiple loads from a single oscillator output discussed in this app note from SiTime. Link here (PDF)

Optimizing board space and managing power consumption of wearable devices is critical in sustaining competitiveness within this fast growing consumer segment. With less power consumed, battery life is extended or provides the option to reduce the battery size. MEMSbased reference clocks offer an alternate to traditional quartz crystal timekeeping components, with advantages including a significant footprint reduction, improved accuracy, and lower system power. In addition, the capability to drive multiple loads with one ultra-small, nano-power oscillator is one way in which MEMS are supporting these improvements.

App note: Tilt-Sensing with Kionix MEMS accelerometers

Kionix low-g acceloreometers used as tilt-sensor. Link here (PDF)

Accelerometers have countless potential tilt-sense applications in today’s motion-enabled world. Tilt-sensing opportunities exist in a variety of industries, such as automotive, consumer electronics and military/aerospace, and include:
• Vehicle stability systems
• Inclinometers
• Cell phone/PDA screen navigation
• Motion-enabled game play
• Tilt-enabled computer mouse/pointer
• Tilt-compensated electronic compass
Some of these applications currently utilize dual-axis accelerometers that, at times, are adequate for the job. A tri-axis accelerometer, however, can enable additional functionality, accuracy and precision.

Inside the Am2901: AMD’s 1970s bit-slice processor

Ken posted an article taking a closer look at AMD’s Am2901 chip:

You’re probably familiar with modern processors made by Advanced Micro Devices. But AMD’s processors go back to 1975, when AMD introduced the Am2901. This chip was a type of processor called a bit-slice processor: each chip processed just 4 bits, but multiple chips were combined to produce a larger word size. This approach was used in the 1970s and 1980s to create a 16-bit, 36-bit, or 64-bit processor (for example), when the whole processor couldn’t fit on a single fast chip.

See the full details on Ken Shirriff’s blog.

Experimental motor driver for CG-4 German equatorial mounts

Dilshan has published a new build:

This is an experimental stepper motor driver for Celestron CG-4 German equatorial mounts. This unit is functionally equivalent to the Celestron dual-axis motor driver, and we developed it as a replacement unit for the original Celestron driver.

See the full post on Dilshan Jayakody’s blog. Project files are available on GitHub.

Building a 12V DC MagSafe charger

Steve blogged about his 12V DC MagSafe charger built:

Now that I have a solar-powered 12V battery, how can I charge my laptop from it? An inverter would seem absurdly inefficient, converting from 12V DC to 110V AC just so I can connect my Apple charger and convert back to DC. It would work, but surely there’s some way to skip the cumbersome inverter and charge a MacBook Pro directly from DC? Newer Macs feature USB Type C power delivery, a common standard with readily available 12V DC chargers designed for automotive use. But my mid-2014 MBP uses Apple’s proprietary MagSafe 2 charging connector. In their infinite wisdom, Apple has never built a 12V DC automotive MagSafe 2 charger – only AC wall chargers. There are some questionable-looking 3rd-party solutions available, but I’d rather build my own.

More details at