AtomSoft uses flex for tiny DimeDuino

From the AtomSoftTech blog:


This time around i give you the DimeDuino. Its a Flex PCB based which utilizes the ATMEGA328P. Using this MCU allows for the installation of the Arduino bootloader. Hence the Duino in the name. These will come pre-programmed with the bootloader. One portion of the circle is just for programming. There is a GND, VCC,RXI, TXO and DTR & RST depending on your programmer.

As soon as its available ill post it here and on Twitter.


  • Atmega328 running at 3.3v/8MHz or 5v/16MHz
  • Power LED (Green)
  • User LED (D13– Color may vary but mainly Blue)
  • Reset Button
  • 3.3v(AP2112K) or 5v (AP7335A) Linear step down
  • Flash 32KB (2KB is Bootloader)
  • SRAM 2KB
  • 20 I/O Pins (A6 & A7 are not used here. Input Only anyway)
    • 1 UART D0 (RX) and D1 (TX)
    • 1 SPI D10 (SS), D11 (MOSI), D12 (MISO), D13 (SCK)
    • 1 I2C A4 (SDA) and A5 (SCL)
    • 6 PWM D3, D5, D6, D9, D10, and D11
    • 14 I/O D0-D13



Olimex designing powerful Linux board with KiCad

Gareth Halfacree writes on Hackster about Olimex’s new project:


Olimex’s Tukhla, Built Around the i.MX8QuadMax, Targets Open-Hardware Linux Power Users

Bulgarian open-hardware specialist Olimex has revealed details of what it describes as its “most complex OSHW board yet:” an NXP iMX8QuadMax-based single-board computer dubbed the Tukhla.

“[A] company from EU which values the OSHW [Open Source Hardware] recognized the absence of high-end open source Linux board and asked us to design one,” Olimex’s Tsvetan Usunov explains. “They offered to cover all associated design costs. They specially requested this to be not yet another [Rockchip] RK3399 board, but based on SoC with proper documentation and software support. NXP’s high end iMX8QuadMax matched their requirements perfectly.”

“Currently all powerful Cortex-A72 comes from Chinese or Korean origin and are always closed projects, the only published info in best case is PDF schematic which can’t be verified i.e. the final product may or may not match what they publish. The popular Raspberry Pi goes even further and their ‘schematics’ are just connector diagrams.”

The Tukhla, by contrast, will be a fully open design, Usunov promises — built in the open source KiCad electronic design automation (EDA) package. Aside from the iMX8 SoC itself — which includes two Arm Cortex-A72 cores, four Cortex-A53 cores, two Cortex-M4F cores, and a quad-core graphics processor with 32 OpenGL ES 3.2 and Vulkan compatible compute units — the board will include up to 16GB of LPDDR4 memory, microSD support, eMMC and QSPI flash storage, a SATA connector, two single-lane PCI Express connectors with NVMe support, HDMI input and output, USB 2.0 OTG and USB 3.0 Host support, two gigabit Ethernet ports, and two MIPI CSI camera connectors.

Olimex designing powerful Linux board with KiCad

Dream Team Members Announced for the 2020 Hackaday Prize

The Dream Team program is an exciting new element of the 2020 Hackaday Prize, with twelve people accepted to work full-time on a specific problem for each of our non-profit partners this summer. Each team of three is already deep into an engineering sprint to pull together a design, and to recognize their efforts, they’ll be receiving a $3,000 monthly microgrant during the two-month program.

Join us after the break to meet the people that make up each of the teams and get a taste of what they’re working on. We’ll be following along as they publish detailed work logs on the Dream Team project pages.

via Dream Team Members Announced for the 2020 Hackaday Prize


Qwiic GPIO expander based on PCF8574

Greg Steiert (@fpgahelper) has shared this Qwiic GPIO expander on

7879121594264360690 (1)

QGPIO: Qwiic GPIO expander based on PCF8574

This is a handy general purpose input/output Qwiic board. It provides 8 GPIO each with an LED indicator, and goes to a pin in a dual row 100mil header. The LEDs provides a nice visual output. The second row on the header is grounded, so jumpers can be used to drive the pins low for basic inputs. The 100mil pitch headers are also convenient for connecting to external circuits as well. The interrupt and VCC pins also have their own LEDs and header pins. There are two Qwiic connectors for pass through connections.


Qwiic GPIO expander based on PCF8574

Give the gift of a personalized PCB keychain

From n°Garage offers personalized one square-inch keychains on Tindie:



This n°Keychain family consists of a series of one-square-inch keychains or pendants. These little beauties are perfect gifts for festival, graduation and remembrance. And more, write lovely words to make it unique and personal.

One order will have two keychains or pendants. To customize it, please choose the option from the drop down above if you would like to add personalized text.

  • Background Words(0~15chars): BRAVE / KIND / Curious / Hindsight 2020
  • Time Mark (0~15chars): Happy New Year / Happy Birthday / Class 2020
  • Name Tag (0~25chars): Alice / Rob / Queen Elizabeth School

If ordering the customizable option, please leave the details of the above inside the field of Additional Instructions at checkout. Please do not exceed the maximum number of characters for each field.

For personalized keychain, it may take about 5 to 9 workdays to ship after ordering. An email notification will be sent to you once shipped. Usually the shipping takes about 10 work-days.

Give the gift of a personalized PCB keychain

Build Your Own RF Lab: Scalar Network Analyzer

Whitney Knitter writes on Hackster about a simple scalar network analyzer that can be controlled by a Raspberry Pi for measuring the frequency response of filters and networks:


Build Your Own RF Lab: Scalar Network Analyzer

With the popularity of wireless applications having become such a staple in the hobbyist community, the need for RF testing capabilities in the hobbyist realm has also increased. Anyone familiar with traditional RF test equipment knows that it is expensive. But challenges like this are what bring out the engineering creativity in this community. Steven Merrifield designed and laid out his own simple scalar network analyzer (SNA) using just a few IC chips. SNAs are handy for testing the frequency response of filters or networks.

A scalar network analyzer is used to test the amplitude of a device’s frequency response by outputting a sine wave sweeping over a certain frequency range (bandwidth) then measuring the amplitude of each incremental output frequency.

Thus if you directly connect the sine wave output of an SNA to its measurement input, then it will read a flat line of the same amplitude for each incremental output frequency of the sweep:

When a device is connected to the SNA, the amplitude of the sine wave at each frequency after going through the device will reflect the device’s frequency response over that bandwidth.

Merrifield’s design accomplishes an SNA’s functionality via implementation of a DDS Synthesizer chip, an ADC, and a logarithmic amplifier chip. The AD9850 DDS is responsible for outputting the sweeping sine wave while the AD8307 logarithmic amplifier conditions the signal input into the SNA for the log of the signal’s envelope before passing it on to the ADC for digitizing. A second AD8307 also conditions the output of the DDS and outputs it to a second channel of the ADC so that it can be used in software for compensation of any variations on the DDS’s output due to the effects of various loads of devices being tested.

The ADC outputs its digital measurements via an I2C interface to a GPIO header that matches the Raspberry Pi’s GPIO header pinout, but any desired MCU or FPGA could be used. The source code Merrifield wrote is in C, making it easy for porting across different platforms.

Check out Merrifield’s project logs here. He linked his PCB layout on OSH Park if you’re interested in ordering it and putting one of these together for your own lab!

Build Your Own RF Lab: Scalar Network Analyzer

KiCad class starts July 7th

Anool Mahidharia will be teaching an introduction to KiCAD and FreeCAD:

Classes are Tuesdays at 19:00 IST. Classes are recorded and released on the course page within a few weeks so you can learn at your convenience. Office Hours are Fridays at 1630 IST and limited to 30 people per session. A second session in evening PDT will be offered August 2020.

The complete course is 4 classes long. For those who would like to attend each class, please sign up for each class individually.

Overview: We’ll start off with a hand drawn schematic, and progress from schematic capture to creating production files such as Gerbers, BoM, and 3D CAD export. We’ll then switch to FreeCAD and do a simple enclosure design for our project.

Schedule: The course will consist of four sessions total. Each section will contain a video component and an office hour component where the instructor will be available for questions.

Prerequisites: It will help to have a good understanding of electronics and some basic understanding of engineering drawing.

KiCad class starts July 7th

This SD Card Won’t Slot

If you’ve got a few self-designed PCBs under your belt, you probably know the pain of missing some little detail and having to break out the bodge wires to fix it. So we feel for [Arsenio Dev], who placed an SD card slot next to an SoC, only to find that it was the wrong way round. Rather than tossing it in the bin, he decided to employ a particularly crafty set of bodge wires that curve over the board and connect to an SD card adapter on the other side.

Our attention was taken by the board itself, he’s posted little information about it and taken pains to conceal one of the pieces of text on it. Since it has an Octavo Systems BeagleBone-on-chip, a slot for a cellular modem, and a connector marked “CONNECT AERONET HERE” which we are guessing refers to the Aeronet sun photometry network, we’re guessing it might be a controller for remotely-sited nodes for that system. Either way it’s enough to have us intrigued, and we wish him every success with the next spin.

via Fail Of The Week: This SD Card Won’t Slot — Hackaday



Reloj: 7400 Series Digital Clock

Alvaro Prieto makes great use of “After Dark” in this digital clock project:

Reloj: 7400 Series Digital Clock

This project was inspired by my dad’s university digital systems project from the late 1970’s. I found the writeup and schematic and decided to try and re-create it. You can see the results of the breadboard reproduction and explanations in this twitter thread.

After a while, I figured it would be fun to make a soldering kit out of it, which resulted in this.


The design is fairly close to the original, but with the addition of a crystal-backed alternate clock source. The 555 timer cock source works, but drifts like crazy, so if you want to use it as an actual clock, you still can with the alt source.

Paper front page


If you want to take a look at the actual paper, you can see the scanned version here.

Design Files

You can get the latest files in the github releases.

For v1.2, you can use my OSHPark shared project or by grabbing the gerbers from the release.

Assembly Instructions

You can find semi-detailed assembly instructions here.

Reloj: 7400 Series Digital Clock