ETA Nixie tube clock

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Mark Smith over at surfncircuits has a nice write-up about building an ETA Nixie Tube Clock:

This DIY project will combine the estimated time of arrival function with a Nixie tube display to create an estimated time of arrival (ETA) Nixie tube clock. It is all easily controlled by a Raspberry Pi Zero W that is connected to the internet through WiFi to provide the latest time and gets the ETA for any number of destinations. The travel time is provided by the free Google Directions API interface that includes traffic to give the best estimates on any particular day.   The goal is that with an ETA Nixie tube clock, no math is needed to add a rough, often optimistic travel time, to the actual time to determine if we are running late.   The clock does that for you and with the power of IOT, is much more accurate!    A motion sensor is also added to the clock to turn off the Nixie Tube Display when no one is around, saving power and increasing the Nixie tube lifetime.

Build log at www.surfncircuits.com. Project files are located at Github.

Arduino time attendance system with RFID

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A how-to on building a time attendance system with MFRC522 RFID Reader and Arduino from Random Nerd Tutorials:

Before getting started it’s important to layout the project main features:
*It contains an RFID reader that reads RFID tags;
*Our setup has a real time clock module to keep track of time;
*When the RFID reader reads an RFID tag, it saves the current time and the UID of the tag in an SD card;
*The Arduino communicates with the SD card using an SD card module;
*You can set a check in time to compare if you are in time or late;
*If you are on time, a green LED lights up, if you are late, a red LED lights up;
*The system also has a buzzer that beeps when a tag is read.

More details at randomnerdtutorials.com.

Check out the video after the break.

How not to build a semiconductor lapping machine

electronupdate writes:

One area of silicon reverse engineering which has interested me is the delayering of a chip to see each layer which allows superior visibility into the circuitry. I know of two ways: chemical etch and mechanical means.
In this video I try to make a mechanical grinder which can take micron levels of material away: a partial success. Parts are ground but I was not able to keep the silicon absolutely flat. More study of the commercial units is warranted!

See the full post on electronupdate blog.

DIY Moteino guide

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Felix writes, “I posted a short illustrated guide for making your own Moteino from SMD components. It also includes details how to burn the bootloader and fuses. Check it out here. Thanks and credit goes to forum user LukaQ for his contribution of the images and test sketches in this guide!

See the full post at LowPowerLab.

Negative impedance converters

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An article discusses the negative resistance and negative impedance converter from Analog Zoo:

“Negative resistance” may seem like a purely academic concept, but can be easily realized in practice with a handful of common components. By adding a single resistor to a standard non-inverting op amp circuit, we can create a negative impedance converter, which has applications in load cancellation, oscillator circuits, and more.

More details at Analogzoo.com.

Check out the video after the break.

Why electrolytic capacitors are actually kinda shitty

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Afroman writes, “Electrolytic capacitors are common, but knowledge of their limitations is uncommon. A demonstration is shown highlighting the difference in performance between electrolytic and ceramic capacitors in power supplies. Other topics discussed in the video: Electrolytic capacitor construction, ceramic capacitors, ESR, ESL, impedance curves, why “0.1uF”, and more.”

Via Afrotechmods.

Check out the video after the break.

Reading a VGA monitor’s configuration data with I2C and a PocketBeagle

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Ken Shirriff wrote an article showing how to read the monitor’s config data using the I2C protocol and a board with an I2C port:

Have you ever wondered how your computer knows all the characteristics of your monitor— the supported resolutions, the model, and even the serial number? Most monitors use a system called DDC to communicate this information to the computer.1 This information is transmitted using the I2C communication protocol—a protocol also popular for connecting hobbyist devices. In this post, I look inside a VGA monitor cable, use a tiny PocketBeagle (a single-board computer in the BeagleBone family) to read the I2C data from an LCD monitor, and then analyze this data.

More details at Ken Shirriff’s blog.

Low cost single cell battery pack simulator

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Mare writes:

There are many battery cell simulators available which could simulate battery cell(s). Unfortunately, none is emulating any of the digital protocols used by fuel gauge devices. Optimal solution to efficiently emulate given smart battery pack is to use custom solution based on battery cell simulator and fuel gauge protocol emulator. Both parts could be fused together in small, but efficient smart battery pack emulator.

  • complete battery cell simulation
  • fast response time
  • unlimited cycle use
  • flexible fuel gauge protocol emulation
  • use of a standard interface for integration in automated test equipment

More details at Mare & Gal Electronics homepage.