For a previous project I explored what it would take to create a text marquee on an 8×8 LED matrix display without microcontroller, using only 7400 chips, an old EEPROM and breadboard components. Matrix Displays I was interested in using an LED matrix display and I picked up some cheap 8×8 ones on Amazon. medium.com That worked, but 8×8 is very small to do anything interesting and so I wanted to give it another go, create a larger 16×16 panel, design a custom PCB and ultimately hook it up to a microcontroller this time to write some games for it.
The rayBeacon by Mike M. Volokhov is a Nordic nRF52 on-the-go development kit:
The Raybeacon is full-featured nRF52 based wearable, ultra-low power, multiprotocol development board designed for variety of embedded applications. Due to modular design, the device can be used to build your own production-ready appliance with minimal hardware modifications.
Key features include:
- Coin sized – the board is only 25 mm in diameter
- Works from a single CR2032 / CR2025 3V button cell
- Nordic nRF52 high-end multiprotocol SoC supporting Bluetooth 5.x, Bluetooth mesh, Thread and Zigbee; of your choice:
- Automotive grade BOM components – ready for harsh environment
- 2 x tactile buttons IP67
- 1 x RGB LED
- 1 x infrared LED (850 nm) 0402 size
- Socket for NFC flex antenna, compatible with Nordic FPC antenna and Liard 0600-00061. Can be configured as extra 2xGPIO.
- Programmable through SWD port (removable Tag-Connect socket, on-board solder pads)
- 1.27mm pitch 2×4 receptacle to connect custom extension boards:
- 6 x GPIO ports
- 1 x 12-bit ADC input
- pass-through VDD and GND pins
- 2.54mm pitch 1×8 pin header for fast breadboard prototyping; can be reused as 1.27 to 2.54 adapter
- USB interface (on-board solder pads)
- Minimal fabrication cost due to simple, two-layers only design
For detailed description, including information on custom boards and source files, please refer to the project repository on Bitbucket. Also, feel free to share your thoughts, or submit a request for a new slice or report an issue!
We really like this “Back to the Future”-themed Flux Capacitor badge add-on (SAO) by Squaro Engineering made with our “After Dark” service (which features clear soldermask on black fiberglass substrate).
Checkout the GitHub repo for more: sqfmi/BTTF-BADGE
The board is also available an OSH Park shared project
- Make my first PCB with an FPGA
- Keep it super simple and cheap
- Configured by on-board FLASH or direct with a Raspberry Pi
- 6 PMODs, 2 buttons, 2 LEDs, FLASH for configuration bitstreams.
What a Lattice iCE40 FPGA needs
- A clock input. Has to be provided by an oscillator, it doesn’t have a crystal driver.
- 1.2v core supply for the internal logic.
- 2.5v non volatile memory supply. Can be provided via a voltage drop over a diode from 3.3v.
- IO supply for the IO pins, different banks of IO can have different supplies. This design uses 3.3v for all banks.
- Get configured over SPI interface. This can be done directly by a microcontroller or a computer, or the bitstream can be programmed into some FLASH, and the FPGA will read it at boot. If FLASH isn’t provided then the bitstream needs to be programmed at every power up or configuration reset.
- Decoupling capacitors for each IO bank.
- FPGA iCE40-HX4K-TQ144 (8k accessible with Icestorm tools)
- 3.3v reg TLV73333PDBVT
- 1.2v reg TLV73312PDBVT
- 12MHz oscillator SIT2001BI-S2-33E-12.000000G
- 16MB FLASH IS25LP016D-JBLE (optional).
See the test program. This makes a nice pulsing effect on LED2, and LED1 is the slow PWM clock. The buttons increase or decrease pulsing speed.
Yosys and NextPNR are used to create the bitstream and then it’s copied to the Raspberry Pi specified by PI_ADDR in the Makefile.
Fomu-Flash is used to flash the SPI memory, or program the FPGA directly.
This is a shitty add-on with one RGB LED controlled by twelve switches. The top row controls the red brightness, the middle row controls the green brightness, the bottom row the blue brightness. Each row of switches is like a 4-bit binary number, giving 16 brightness options for each color channel.
Should I have used knobs instead of switches? Maybe, but then it’s not a shitty add-on, is it?
Each color channel is controlled by its own ATtiny10, reading an analog voltage and PWMing the LED accordingly. The ATtiny10s are programmed using [Simon Merrett]’s SOICbite footprint, which I *love*.
Should I have used a 555 instead of a microcontroller? Perhaps. But isn’t this a better solution for a shitty add-on?
The Open Hardware Summit is next week, March 13th!
Here’s a sneak peak at one of the items that everyone will receive in their conference goodie bags:
Thanks so much to Kevin Walseth at Digi-Key for making it happen! ⚡️
Special edition Z80 based retro computer kit with stunning After Dark PCB
Fundamentally, this is an RC2014 Mini. A single board Z80 computer that runs BASIC or Z80 assembly code. If you are looking for an easy to build, good looking, well supported Z80 single-board computer, you probably should just go and buy a RC2014 Mini
However, if you are after a stunning looking Z80 single board computer which is one of only 25 in the world, then read on…
Limited Edition RC2014 Mini After Dark
- Amazingly beautiful AfterDark PCB from OSHPark features black FR4 substrate, 1oz copper with clear solder resist, ENIG (gold) pads and white silkscreen
- Every track from the original RC2014 Mini has been relaid for maximum visual appeal
- RC2014 logo in the top copper layer
- Turned pin chip sockets
- White connectors, jumpers and reset switch to compliment the silkscreen
- Laser-cut mirrored base plate with brass PCB standoffs allow the underside of the board to be seen
- Rubber mounting feet
- Limited run of 25 kits, with each one being numbered. Kits will be supplied strictly in number order and records kept if later verification is required
- Option to buy a standard RC2014 Mini with a 50% discount so you can hack around and modify the standard RC2014 Mini whilst leaving the Limited Edition RC2014 Mini After Dark kit intact. Or mix & match the black and white connectors to create your own unique RC2014.
- Same specification as standard RC2014 Mini (Z80 processor at 7.3728MHz, 32k RAM, ROM with Microsoft BASIC / SCM Monitor, 5v power over USB barrel jack cable or FTDI cable, 115,200 baud serial communication, keyboard connector for Universal Micro Keyboard, Pi Zero header option for Pi Zero Serial Terminal
- Luxury packaging for that unique “unboxing experience”
- Shipping will automatically be upgraded to signed, tracked or recorded delivery based on your location
- Limited run RC2014 After Dark stickers
Max.K on Hackaday.io has created a pocket sized ESP32 display board with 300µW Always On Display:
This handheld board is powered by an ESP32 and features a transflective Sharp memory LCD. Similar to my previous Chronio smartwatch the focus of this project is on low power consumption. Using the ESP32’s ULP core, the board can go into deep sleep with an active display. The software includes a menu interface with a simple RSS reader.
Some of the key features are:
– 400x240px 2.7″ SHARP memory display
– 350 mAh LiPo battery with USB charging
– Always On Display with 300 µW power consumption
– 4-way joystick and buttons
– Date and time using built in RTC with NTP sync
– RSS Feed / Website parser
Layout files and Code on GitHub: https://github.com/CoretechR/ESP32-Handheld
To load data you need an EEPROM programmer and like the chips, these devices have become somewhat rare and expensive. Hence the project to build one ourselves.
The easiest approach is probably to use a microcontroller to bridge between the chip and a computer, run a bidirectional serial protocol between the microcontoller and the computer to send image data back and forth.
Since the AT28C256 requires 5v for writing, we can’t use a Raspberry Pi or Arduino Nano/Mini as their GPIO ports are all 3.3v. The regular old Arduino UNO is 5v though and so should work nicely.
To gain some experience hand-soldering surface mount devices, I picked SMT packages for the shift registers and decoupling capacitors.
The ZIF socket is a 40 pin device I had lying around. Since the AT28C256 is a 28-DIP, I just left the 12 left-most pins unconnected. It’s a low budget project.
When I went to upload the Gerber files to OshPark for fabrication I noticed their “ After Dark “ option that uses a black FR4 substrate, with transparent soldermask that makes the copper traces pop against a black background.