Monthly Archives: September 2017

Winner, Name that Ware August 2017

via Hacking – bunnie's blog

The ware for August 2017 is the controller IC for a self-flashing (two-pin, T1 case) RGB LED. It’s photographed through the lens of the LED, which is why the die appears so distorted. Somehow, Piotr — the first poster — guessed it on the first try without much explanation. Congrats, email me for your prize!

Free PCB coupon via Facebook to 2 random commenters

via Dangerous Prototypes

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook 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.

Homemade 6 GHz FMCW radar

via Dangerous Prototypes

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Henrik Forstén has a nice build log on his newest version of this homemade 6 GHz FMCW radar:

Frequency Modulated Continuous Wave (FMCW) radar works by transmitting a chirp which frequency changes linearly with time. This chirp is then radiated with the antenna, reflected from the target and is received by the receiving antenna. On the reception side the received signal that was delayed and undelayed copy of the transmitted chirp are mixed (multiplied) together. The output of the mixer are two sine waves that have frequencies of sum and difference of the waveforms. The frequencies of the received signals are almost the same and the sum waveform has frequency of about two times of the original signal and is filtered out, but the difference waveform has frequency in kHz to few MHz range. The difference frequency is dependent on the delay of the received reflection signal making it possible to determine the delay of the reflected signal. The electromagnetic waves travel at speed of light which allows converting the delay to distance accurately. When there are several targets the output signal is sum of different frequencies and the distances to the targets can be recovered efficiently with Fourier transform.

See the full post on his blog. Project files are available at github.

Maker builds an Arduino-controlled, chess-playing robot

via Arduino Blog

While playing board games on a computer screen can be entertaining, this experience lacks a certain tangible aspect. YouTuber RoboAvatar decided to take things into the third dimension with a chess machine that uses an XYZ gantry system and gripper to move pieces as needed.

Instead of a vision system, RoboAvatar’s robotic device uses 64 reed switches (one for each square) to tell an Arduino Uno where the magnetized pieces reside. The project also features a Mux Shield and a pair of MCP23017 I/O expander chips, providing a total of 93 available pins.

While the Uno controls the physical motion and sensing of the board, a computer runs a Python program that does the chess game calculations and sends this information to it. You can see the machine demonstrated in the first video below. The second gives an overview of how it was made.

Want to build your own chess-playing robot? More details can be found over on Instructables.

How to build your own RS232 to TTL converter

via Dangerous Prototypes

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A how-to on making a DIY RS232 to TTL converter by Jestine Yong:

As I read many pages on the internet I saw there is a sort of adapter so called “USB to TTL adapter” who can communicate through with the uC. I had not the time to order one but I give a try to make one for the COM port. Actually it is an RS232 to TTL converter which I found better from my opinion than that USB to TTL adapter.
Here is why I like more this RS232 to TTL adapter than the other one:

  • can be used on a real RS232 port
  • it is a stable voltage level converter
  • can be used on USB port too (through USB to RS232 converter)
  • there is no VCC ( somebody would say it’s a disadvantage but wait…) *
  • it is a real hardware stuff, no emulation etc. (if it is used through a real com port)
  • can be built really cheap and easy

More details at Electronics Repair site.