Using modular synth to control Atem camera switching over WiFi using ESP8266

Sebastian writes:

I’ve been wanting to control my camera switching from my modular synth. So I made a setup where a low to high transition on a digital input on an ESP8266 module generates an OSC message on the WiFi network for the ATEM Mini Pro switcher to change cameras. Here, it’s triggered from the kick but it could be any clock, gate or trigger signal. Makes use of atemOSC.

More details on Little-Scale blog.

Check out the video after the break.

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#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.

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Experimental Zener diode tester

Dilshan has published a new build:

Automatic Zener diode tester is capable of identifying Zener diodes up to 27.5V. Apart from that, it can be used to recognize leads of the diodes/Zeners and detect damaged diodes. This tester is designed using well-known ICs such as MC34063 and PIC16F88.
This unit provides approximately 5% to 15% accurate readings. Based on our observations, the accuracy of this unit can increase by using resistors with 1% tolerance, stable booster circuit, accurate sampling method(s), and with a more optimized PCB layout.

More details on Dilshan Jayakody’s blog. Project files are available on GitHub.

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App note: P-channel power MOSFETs and applications

Another app note from IXYS on P-Channel power MOSFET application. Link here (PDF)

IXYS P-Channel Power MOSFETs retain all the features of comparable N-Channel Power MOSFETs such as very fast switching, voltage control, ease of paralleling and excellent temperature stability. These are designed for applications that require the convenience of reverse polarity operation. They have an n-type body region that provides lower resistivity in the body region and good avalanche characteristics because parasitic PNP transistor is less prone to turn-on. In comparison with Nchannel Power MOSFETs with similar design features, P-channel Power MOSFETs have better FBSOA (Forward Bias Safe Operating Area) and practically immune to Single Event Burnout phenomena. Main advantage of P-channel Power MOSFETs is the simplified gate driving technique in high-side (HS) switch position.

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App note: Parallel operation of IGBT discrete devices

Guidelines for parallel operation of IGBT devices discuss in this app note from IXYS. Link here (PDF)

As applications for IGBT components have continued to expand rapidly, semiconductor manufacturers have responded by providing IGBTs in both discrete and modular packages to meet the needs of their customers. Discrete IGBTs span the voltage range of 250V to 1400V and are available up to 75A (DC), which is the maximum current limit for both the TO-247 and TO-264 terminals. IGBT modules cover the same voltage range but, due to their construction, can control currents up to 1000A today. However, on an Ampere per dollar basis, the IGBT module is more expensive so that for cost-sensitive applications, e.g. welding, low voltage motor control, small UPS, etc., designs engineers would like to parallel discrete IGBT devices.

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cVert, a truly random MIDI controller

cVert, a truly random MIDI controller @ danny.makesthings.work

cVert is the result of an idea I’ve been kicking around for years, and took a few months of work to bring to fruition. The idea was to use a Geiger counter as a true random number generator to give a non-deterministic input for computer art or music. The result is a MIDI controller with a large amount of control removed – it plays a random musical note every time a radioactive decay is detected.

All files are available on GitHub.

Check out the video after the break.

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DIY home made portable oscilloscope

An ATmega328 based portable home made oscilloscope with ADC from Creative Engineering:

It is basically a small scaled digital oscilloscope. It is capable of displaying all type of waveform like sine, triangular, square, etc. It’s bandwidth is above 1 MHz and input impedance is about 600K. The device is mainly using the ATmega328 micro-controller as the heart and is assisted by a high performance ADC (TLC5510) which is capable of taking up-to 20 mega samples per second and thus increasing the span of bandwidth which can be analyzed by our device. In addition to that, in-order to make the device portable Li-ion battery is used , which will be suitable to be fitted into a confined space.

See project details on Creative Engineering blog.

Check out the video after the break:

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Repairing an HP 3438A digital multimeter

Jeff (aka K6JCA) did a repair of an HP 3438A digital multimeter and documented the whole process on his blog:

This blog post is a record of my notes made while repairing an HP 3438A Digital Multimeter I had picked up last year at a local electronics swap meet. The 3438A is a 3.5 digit HP-IB controllable multimeter. It has five selectable functions: DC Volts, AC Volts, DC Amps, AC Amps, and Ohms. Of these five functions, three can be auto-ranged: DC Volts, AC Volts, and Ohms.

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Extracting ROM constants from the 8087 math coprocessor’s die

Ken posted an article taking a closer look at Intel 8087 chip:

Intel introduced the 8087 chip in 1980 to improve floating-point performance on the 8086 and 8088 processors, and it was used with the original IBM PC. Since early microprocessors operated only on integers, arithmetic with floating-point numbers was slow and transcendental operations such as arctangent or logarithms were even worse. Adding the 8087 co-processor chip to a system made floating-point operations up to 100 times faster.
I opened up an 8087 chip and took photos with a microscope. The photo below shows the chip’s tiny silicon die. Around the edges of the chip, tiny bond wires connect the chip to the 40 external pins.

More details on Ken Shirriff’s blog.

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Arduino to Nokia 84×48 LCD Heartbeat Display

Bob writes:

I am working on some Arduino biometric designs perhaps for a new book. So far I have created the two line 1602 LCD display and now the Nokia 84×48 display. The Nokia display is more fun to work with since I can do a oscilloscope like display across the screen. I am working on writing code that works with both an Arduino UNO and with the ESP8266 or the “D1” board.
You can connect a NOKIA display easily using a header extender. You only need to connect five pins this way. The other two are power and ground and they use jumpers to 3.3 Volts and ground.

More details on My Commentary and Technical help blog.

Check out the video after the break.

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