Yield function, printable class and mapping arrays: Useful but unknown features from Arduino core

test-printable-arduino-1

Yahya Tawil over at Atadiat wrote a new tip for Arduino developers about three hidden and useful features in Arduino core:

Arduino core, the source code of Arduino API functions and classes, has three useful features that can be used effectively. As the Arduino core documentation doesn’t mention them (at least until the time of publishing this micro-blog), these features are not well-known for arduino developers. Let’s discuss each feature of them one by one.

More details at Atadiat blog.

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Common emitter amplifier design tips & shortcuts

Tips & tricks for the common emitter amplifier design by Alan Wolke (aka W2AEW)

This video provides some basic design tips and shortcuts for the Common Emitter, Class A, Amplifier. The considerations for selection of the DC Bias point are presented, as well as some tips on how to set/compute the gain for both degenerated and high-gain configurations.

Pimp your PCB businesscard full color

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Here is a nice PCB businesscard @ smdprutser.nl

As a good electronic hobbiest tradition I started to design a businesscard from PCB material. Downside of all the businesscards (and PCBs in general) is the limited number of colors you can use: FR4, soldermask (with or without copper behind it), silkscreen or bare copper. Since the soldermask is fixed for both sides that was an extra limiting factor.
An out of the box solution I found was decal slide paper. This is a printable plastic film that is used to decorate ceramics or glass. There are clear and white versions and they can be found in most hobby stores. They are easily printed on by an inktjet or laser printer and have thus an infinite range of colors. For this experiment I bought clear film and designed the PCB with black soldermask (needed that color for the front side) and white silkscreen.

More details here.

Using Python to store data from many BLE devices

raspberry-pi-with-python-controlling-a-set-of-hexiwear-ble-devices

Erich Styger has written an article describing a technique he used to collect and store data from several BLE devices with Raspberry Pi and Python scripting:

BLE (Bluetooth Low Energy) sensor devices like the Hexiwear are great, but they cannot store a large amount of data. For a research project I have to collect data from many BLE devices for later processing. What I’m using is a Python script running on the Raspberry Pi which collects the data and stores it on a file

More details at mcuoneclipse.com.

Modifying the Teensy 3.5 and 3.6 for ARM SWD debugging

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Erich Styger @ mcuoneclipse.com writes:

Looking for a small, inexpensive ($25-30) ARM development board (say 120-180 MHz ARM Cortex-M4 with FPU, 512kB-1MB of FLASH and 256 KByte of RAM? Then have a look at the Teensy 3.5 and Teensy 3.6 by PJRC/Paul Stoffregen
The only problem? it is not possible to debug it :-(. At least not in the traditional sense. This article is about how to change the board to use it with any normal SWD debugging tool e.g. Eclipse and the Segger J-Link :-).

More details at MCU on Eclipse homepage.

Enhancing Arduino ADC resolution with dithering & oversampling

osditheredtemp1-600

From the comments on our previous post Improving ADC resolution by oversampling and averaging application note, Edward Mallon writes:

I managed to get oversampling working well on cheap Arduino promini clones. Turns out all you have to do is toggle a digital pin connected to ground with the right size resistor to generate enough noise for the technique to work.

More details at Arduino based underwater sensors homepage.

EAGLE: Panelizing made easy

mousebite

Sjaak shared a tip for panelizing PCB boards in Eagle:

Panelizing is done by machining a slot between two or more boards, but keep them attached by a small amount of PCB material (mousebites). I used to do it by hand: generated all the schematics into multiple sheets and then route the board and finally add the slots with mousebites in the PCB editor. I generally use slotwidth of 50 mil and the smallest drill possible (12 mil) 12.5 mil apart as breakingline. I tend to place the mousebites about 2cm from each other to maintain PCB strength.

The handy feature I found is in the PCB editor (schematics has one too!) is to import an other PCB design. First you design the boards individually and then import them all into an empty board file and place them 50 mil from each other, add mousebites to taste and send them off 🙂

More details at smdprutser.nl.