Custom 3D printed magnetic encoder disks for robotics projects

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A how-to on making a custom DIY magnetic disk encoder by Erich Styger:

I’m making great progress with the firmware for the new Mini Sumo Robot (see “New Concept for 2018 Mini Sumo Roboter“). The goal is a versatile and low-cost Mini Sumo robot, and the robot comes with the feature of magnetic position encoders. In a previous article I have explained how to mold custom tires for robots (see “Making Perfect Sticky DIY Sumo Robot Tires“), this article is about how to make DIY Magnetic disk encoders.

Via MCU on Eclipse.

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ESP8266 Wi-Fi button – DIY Amazon dash button clone

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Rui Santos over at Random Nerd Tutorials posted a step by step guide on building an ESP8266 Wi-Fi button:

In this project you’re going to build an ESP8266 Wi-Fi Button that can trigger any home automation event. This is like a remote control that you can take in your pocket or place anywhere that when pressed sends out an email. It can also be called a DIY Amazon Dash Button clone.

Check out the video after the break.

 

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Yellowstone JTAG debugging

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A follow-up to the FPGA-based disk controller for Apple II post, Steve writes:

After a month of inactivity, I finally returned to my unfinished Yellowstone disk controller project to investigate the JTAG programming problems. Yellowstone is an FPGA-based disk controller card for the Apple II family, that aims to emulate a Liron disk controller or other models of vintage disk controller. It’s still a work in progress.
Last month I discovered some JTAG problems. With the Yellowstone card naked on my desk, and powered from an external 5V supply, JTAG programming works fine.

More details at Big Mess o’ Wires.

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#FreePCB via Twitter to 2 random RTs

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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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The traveling wave tube inside HP 493A is radioactive

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Kerry Wong writes, “In my previous video featured on EEVBlog I did a teardown of an HP 493A microwave amplifier along with the traveling wave tube inside. I actually had done a teardown of an identical unit a while ago but this time I managed to take a peek at the traveling wave tube inside.”

More details on his blog here.

Check out the video after the breaks.

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Xerox Alto’s 3 Mb/s Ethernet: Building a gateway with a BeagleBone

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Ken Shirriff documented his experience building a gateway using the BeagleBone single-board computer to communicate with the Alto’s Ethernet we covered previously:

I decided to build a gateway that would allow the Alto to communicate with a modern system. The gateway would communicate with the Alto using its obsolete 3Mb/s Ethernet, but could also communicate with the outside world. This would let us network boot the Alto, transfer files to and from the Alto and backup disks. I expected this project to take a few weeks, but it ended up taking a year.

See the full post at Ken Shirriff’s blog.

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Free PCB Sunday: Pick your PCB

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Be sure to use a real e-mail in the address field so we can contact you with the coupon.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.
  • PCBs are scrap and have no value, due to limited supply it is not possible to replace a board lost in the post

Be the first to comment, subscribe to the RSS feed.

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App note: Adding flexibility by using multiple footprints for I2C™ serial EEPROMs

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Save PCB space by utilizing EEPROM SOIC-8 area, here’s an application note from Microchip. Link here (PDF)

For many years, the 8-lead SOIC package has been the most popular package for serial EEPROMs, but now smaller packages are becoming more commonplace. This offers a number of benefits; the reductions in footprint size and component height are some of the more obvious ones. Smaller packages also generally offer a cost advantage over their larger counterparts.

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App note: Writing to flash and EEPROM on the tinyAVR 1-series

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Update your tinyAVR code to access memories when using 1-series tinyAVRs. Link here (PDF)

On tinyAVR® 1-series devices, access to Flash memory and EEPROM has been changed from that on previous tinyAVR devices. This means that existing code for writing to Flash and EEPROM on older devices must be modified in order to function properly on tinyAVR 1-series devices. This application note describes what has changed and how to adapt code to these changes.

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STM32F103 vs GD32F103

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Sjaak wrote about a Chinese ARM chip compared to a ST ARM chip:

Most of us do know the ST line of ARM chips called STM32. They come in multiple flavours and the STM32F103 is one of the most common entry level family of chips. They are called by ST as mainstream. They are a full featured 32 bit ARM Cortex M3 chip running at max. 72MHz with all the requisite peripherals like ADC, DAC, USB, CAN, I2C, I2S, SPI, SDIO, PWM, RTC, interrupts and various timers. Lets zoom into the STM32F103C8 chip (which seems the be the go-to choice of the Chinese el-cheapo development breakout boards)

See the full post at smdprutser.nl.

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