Reflowduino: Put That Toaster Oven To Good Use

From  on the Hackaday blog:

Reflowduino: Put That Toaster Oven To Good Use

There are few scenes in life more moving than the moment the solder paste melts as the component slides smoothly into place. We’re willing to bet the only reason you don’t have a reflow oven is the cost. Why wouldn’t you want one? Fortunately, the vastly cheaper DIY route has become a whole lot easier since the birth of the Reflowduino – an open source controller for reflow ovens.

This Hackaday Prize entry by [Timothy Woo] provides a super quick way to create your own reflow setup, using any cheap means of heating you have lying around. [Tim] uses a toaster oven he paid $21 for, but anything with a suitable thermal mass will do. The hardware of the Reflowduino is all open source and has been very well documented – both on the main page and over on the project’s GitHub.


The board itself is built around the ATMega32u4 and sports an integrated MAX31855 thermocouple interface (for the all-important PID control), LiPo battery charging, a buzzer for alerting you when input is needed, and Bluetooth. Why Bluetooth? An Android app has been developed for easy control of the Reflowduino, and will even graph the temperature profile.

When it comes to controlling the toaster oven/miscellaneous heat source, a “sidekick” board is available, with a solid state relay hooked up to a mains plug. This makes it a breeze to setup any mains appliance for Arduino control.


Reflowduino: Put That Toaster Oven To Good Use

ATTiny wearable by Facelesstech

tl;dr It’s a foundation for a wearable platform. It’s a Nato watch strap threaded through a PCB with a coin cell battery holder between the PCB and the strap. I’m using a Attiny85 this time around but could be used for most chips/dev boards. This is a proof of concept to iron out any problems […]

via Attiny wearable — Facelesstech

ATTiny wearable by Facelesstech

Building a Giant USB Three Key Mechanical Keyboard

From Jeremy S. Cook on the Hackster blog:


Ginormous 3-Switch Keyboard Is Awesomely Impractical

As hackers and creators, we sometimes get asked the question “why?” While many of the gadgets we make do have a specific purpose, many of them definitely don’t, and are made because we wonder if something can actually be done. This giant three-key mechanical keyboard would certainly fall into that second category, and though I can’t think of a practical use for it, I still find the device quite entertaining.


The heart of this device is a trio of “Big Switch” devices from Novel Keys, which are four times larger in length/width/height than what you’re used to typing on. While that might sound only sort of interesting, that translates to 64 times normal size in volume; plus they include similarly ginormous keycaps. Glen Akins, inspired by a similar project on Adafruit, decided to build his own 3-key array, with a PIC18F14K50 chip providing an interface between the keys ans USB input.


The housing is made out of aluminum, and sits at an angle to the user for excellent ergonomics — if you happen to be a giant, and only use three keys at a time. While the electronics are fairly straightforward, these large keys are electrically quite noisy. Debounce code was added to combat this, reducing the letters per keypress from a range of one to three to only a single character.

Read more on Glen’s own Photons, Electrons, and Dirt blog:

Building a Giant USB Three Key Mechanical Keyboard

Building a Giant USB Three Key Mechanical Keyboard

iceRadio SDR project

Software Defined Radio (SDR) project by Eric Brombaugh:


This is a test prototype for experimenting with Software Defined Radio (SDR). It is composed of several boards that are described in detail elsewhere on this site:

Combined with suitable firmware and FPGA design, these boards comprise a receiver capable of capturing 20kHz of signal from DC to over 1GHz, demodulating it with a variety of formats and driving high-quality audio.



RF input from the antenna can optionally be tuned down from VHF/UHF frequncies to an IF frequency in the HF range before passing to the ADC.


Raw HF or downconverted VHF at an IF of 5MHz is digitized to 14-bit resolution. The maximum input signal allowed without exceeing the range of the ADC puts the 0dBfs point of this system at -10dBm in 50 ohms. The ADC runs at 40MSPS with a resolution of 10 bits, providing approximately 60dB of dynamic range and 20MHz of bandwidth which places the quantization noise floor at about -70dBm.


From the ADC, data passes into the FPGA. This is an iCE5LP4k part which provides 20 4kb RAM blocks and 4 16×16 MAC blocks which are essential for the DSP required for the downconversion. In the FPGA the ADC data is pre-processed to a sample rate appropriate for the MCU. Figure 2 below shows the primary components of the FPGA design.


The C and Verilog source code is available on GitHub:


iceRadio SDR project

Dock for Onion Omega2

Valerio Backslashnew has designed a small dock for the Onion Omega 2 and 2+:


My Omega 2/2+ dock\new

I needed the smallest dock i could do, that featured:

  • Ethernet
  • Type A USB host
  • Micro USB for power

Here’s what i came up with, i called it dock\new.


It has an onboard linear voltage regulation (i didn’t bother going with a switching one for such low power), magnetics integrated in the RJ45 connector to save space, USB host ESD protection (diode array), USB host PTC fuse.

On the left side there is the RJ45 connector and nothing on the back side of the board, so that you can easily access the MicroSD card on the Omega 2+.

On the right side (the antenna side of the omega) you have the USB type A connector, facing outwards, and the microusb connector for power, facing inwards.

The project is open source (CC-BY-SA 4.0), and the KiCad schematics, board layout and the other files are available on GitHub:



5N44P has shared the board on OSH Park:


Order from OSH Park

Dock for Onion Omega2

reDot Smart 5×7 LED Matrix

Alex on is working on a smart miniature (DIP6) 5×7 LED Matrix:



This project is based on my #reDOT project. Basicly it is a 5×7 SMD LED Matrix an a microcontroller on one PCB. I started wirh 0201 LEDs (see first project log), but this was not reliable. So a second version with 0402 is in development. 0402 LEDs do have some benefits over 0201:

  • bigger and you can solder them better
  • cheaper
  • more colors availible

The microcontroller (a low coast STM8) drives all LEDs directly with multiplexing. For controlling a UART interface is available. The dimensions are like a DIP-6 package. For easy connection of multiple PCBs, the pads are castellated. Also the supply rails are available on both sides. So multiple of these display can be soldered together to a bigger display without the need of additional wiring.

reDot Smart 5×7 LED Matrix