While this turntable can’t play “Dark Side of the Moon”, it certainly can tell you which way it’s facing! This project by Yingjie Bei and Yifan Hu uses an Arduino to position a turntable and associated light source in such a way that the moon replica mounted on the turntable will be illuminated to demonstrate the current moon phase.
Project log and details can be found on Bei’s website.
Via Engadget.
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:
App note(PDF) from Murata on output capacitors loading when in a switch mode power supply
There are numerous factors to consider when adding external capacitors to switched-mode power supplies (SMPS). This article will discuss noise, startup, ESR, stability, pre-bias applications, Sense inputs, On/Off (remote enable) controls and other topics.
Many real-world DC/DC applications require external bypass “bulk” capacitors as part of the output load. These capacitors supply extra current during a step load change. Lower DC voltages used in newer logic devices mean that the voltage margin difference between logic ZERO and logic ONE is reduced to hundreds or even tens of millivolts. Thus, since even modest power supply noise can cause data errors by exceeding this threshold, these bypass caps are necessary to reduce this DC/DC noise.
A great guide (PDF) to electromagnetic compatibility from Murata
International regulations regarding electromagnetic compatibility (EMC) affect many aspects of circuit and system design. However, there are many techniques that can be applied generally to reduce both the emissions from and susceptibility to, electromagnetic interference (EMI).
As a manufacturer of electronic components, Murata Power Solutions is committed to minimizing emissions from its own components and to helping its customers achieve EMC compliance by correct component choice and design. To this end Murata Power Solutions has compiled the following list of general design recommendations.
An application note from TI, TPS6122x low input voltage, 0.7V boost converter with 5.5μA quiescent current (PDF!):
The TPS6122x family devices provide a power-supply solution for products powered by either a single-cell, two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-Ion or Li-polymer battery. Possible output currents depend on the input-to-output voltage ratio. The boost converter is based on a hysteretic controller topology using synchronous rectification to obtain maximum efficiency at minimal quiescent currents. The output voltage of the adjustable version can be programmed by an external resistor divider, or is set internally to a fixed output voltage. The converter can be switched off by a featured enable pin. While being switched off, battery drain is minimized. The device is offered in a 6-pin SC-70 package (DCK) measuring 2 mm x 2 mm to enable small circuit layout size.
Kristian Lauszus writes, “In this blog post I will describe a IoT (Internet of Things) Vending Machine that I built quite some time ago with a friend of mine Sigurd Jervelund Hansen. At Sigurd’s dorm room they got hold of an old vending machine free of charge, as it did not work. We quickly decided that we wanted to get it working and give it a overhaul as well. In the end we enabled it to take both RFID/NFC cards and coins and make funny twitter updates about it.”
The source code available at Github. More details at TKJ Electronics blog.
Check out the video after the break. Continue reading “IoT Arduino vending machine”
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:
Continue reading “Free PCB coupon via Facebook to 2 random commenters”
Hendrik Lipka has written up documentation on his SPG8640-based crystal frequency generator:
When I needed a small frequency generator for a project several years ago, I did neither had the time nor the skills to build something like that. But I had in my parts box a nice chip that seemed perfect for a small tool – the SPG8640BN.
This small chip is a crystal osciallator combined with a configurable divider. The specific ‘BN’ version has a 1MHz oscillator, one divider up to 1:12 and one divider up to 1:107sup>. So it can generate an output from 1/120th up to 1MHz. Nice. Configuration of the output frequency happens via several control pins. The first three select the base frequency, as the control the 1:12 divider. The selectable dividers as 1, 2, 3, 4, 5, 6, 10 and 12. The other three control pins control the second divider, and select the division stage – with each stage dividing by 10. So we have 8 different base frequencies, and each can span 8 decades.
Project info at Hendrik’s blog.
MAKE has posted Alasdair Allan’s three part series concerning the ESP8266 MCU. Alasdair highlights the capabilities and limitations of this chip, the installation and use of a supporting version of the Arduino IDE, and how to create a breadboard adapter for the ESP-01 breakout board (pictured above.)
Via MAKE.
Ray Wang from RaysHobby has written an article on his ESPToy 1.2, a ESP8266 development board based on the Lua firmware:
A little while back I released the very first version of ESPToy — a ESP8266 Development Board with a few useful on-board components like color LED, button, and temperature sensor. It has a built-in ATmega644 microcontroller, and pin headers for plugging in a ESP-01 through-hole WiFI module. Shortly after that, I discovered the Lua firmware (named nodemcu) for ESP8266. At first I didn’t pay much attention — Lua is a new language that I’ve never used before, and I wasn’t sure if it’s worth my time learning about it. At the same time I was getting tired of the AT firmware (the original firmware that comes with ESP), partly because it’s not very stable, and partly because it’s complicated to use and involves an extra microcontroller to communicate with it.
Over time I saw increasing development and community support on the Lua firmware. So I became more curious. The final push came recently: there was a supply chain problem of the ATmega644 microcontroller. I was about to purchase a new batch of ESPToy 1.1, but the microcontroller is difficult to source from my suppliers in China. I decided that I should give the Lua firmware a try — if it works, I don’t have to use an extra microcontroller any more!
Details can be found in Ray’s blog post.
Check out the video after the break. Continue reading “Introducing ESPToy 1.2 (with Lua Firmware)”
In this video Ben Krasnow of Applied Science demonstrates how he collect digital electron microscope images with his Tek MDO3000 oscilloscope.
Via contact form. Thanks Jan Henrik!
Ugifer wrote this instructable detailing the build of his Arduino based high-altitude balloon tracker:
The tracker is based upon the Atmel ATMeag328 Microcontroller which forms the heart of many of the popular “Arduino” boards. We are going to make an “Arduino Compatible” board which we can program using the Arduino IDE.
Because the GPS module and SD card both require 3.3v and we have plenty of computing power, we may as well make the whole tracker run on 3v3. That means that we can’t clock the ‘328 up to its full 16MHz but it will run happily at 8MHz on 3v3, and that’s plenty for our purposes.
Check out the video after the break. Continue reading “Arduino based high-altitude balloon tracker”
jscottb over at LetsMakeRobots writes:
My goal for this mini project is to create A simple autonomous rover with just the ESP and NodeMCU. In looking at the specs for node most of the supporting libraries already written. GPIO, PWM and Timer libraries are included in the Lua interpreter.
After flashing the board my next up was to write the base code I would use for the bot. My first step in writing it was the stub out something I could test locally on my machine with standard Lua. I did this by making fake functions for the GPIO and tmr classes. This allowed me to check my code for syntax errors before uploading to the board. After this is done, the code was uploaded and verified with the real Node Lua.
I decided to write the code similar to processing and Arduino code with a setup and loop function. Outside of that, I have four functions and they are as follows; forward, back_up, turn_left and read_usonic.
Project info at LetsMakeRobots blog.
Check out the video after the break. Continue reading “ESP8266 running NodeMCU as a controller”
Bus Pirate v3.6 acrylic case v1 (DP6037) is back in stock at Seeed Studio. A clear laser-cut acrylic case kit for the Bus Pirate v3.6.
Check out our tutorial on how to customize Sick of Beige cases.
Get Bus Pirate v3.6 acrylic case v1 for $3.
Martin Raynsford has written an article detailing his 40W handheld laser cutter:
To generate the high voltage required to start lasing within the tube, I connected 200x 9V ‘dead’ batteries together, this generates nearly 2000V across the laser tube. I’ve been collecting these batteries for months, you can use old batteries for this because they only need to provide power for a fraction of a second, this is enough to generate a short pulse of laser light.
Normally the input would be switched at 2Khz to generate a continuous output from the tube, but making a switching circuit from a DC power supply (a battery) involves some complicated electronics, this stack of 9V batteries is a quick way to produce the high voltage, low current required to activate the tube.
Even with these short pulses of light the tube can heat up quickly so I installed a small 6W water pump to push water through the cooling jacket. The pump is not very good at drawing a vacuum so the reservoir was stored above the pump so it could gravity feed. The pump was powerful enough to push a sensible amount of flow around the tube and back into the bottle.
Project info at Just Add Sharks site.
Check out the video after the break. Continue reading “40W handheld laser cutter”
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:
Some stuff:
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.
Sverre Holm writes:
There are several low power transmitters around that can be purchased, but most of them only cover the mediumwave band and not longwave (153-279 kHz). Further they are quite complicated as the frequency necessarily has to be user settable.
I looked for a simpler way to make a single-frequency transmitter and found that the function generator chip XR-2206 which I happened to have in my junk box could both generate this frequency and do the amplitude modulation. The RC-oscillator seems to be stable enough for this low frequency although I haven’t tested this much.
Here are the first results with images of the circuit on a Veroboard and the oscilloscope picture of the modulation with my Tandberg TP41 70’s radio on top of it listening to Dire Straits from Spotify streaming over longwave.
The circuit has very little output power, lacks antenna tuning and harmonic filtering, so there is room for improvement, but at least it works.
More details at LA3ZA Amateur Radio blog.
Marcus Jenkins blogged about his TDR pulse generator build:
I saw an excellent YouTube video from Alan W2AEW and thought I’d have a go at making a prettier version of the tool myself. After all, checking 50 Ohm coax cables is a pretty common need for an amateur radio enthusiast.
Alan’s video says it all, but here’s a top-level overview. You feed a fast-edged pulse into one end of a coax cable and use your oscilloscope to measure the time it takes for the pulse to travel all the way to the other (unconnected) end, bounce, and come back. If you know the characteristics of the cable, you can calculate the length of the cable (or the distance from your measurement point to the first break in the cable). The circuit described in Alan’s video and this article makes such a fast-edged pulse.
With this setup you can measure the length of cable, find breaks in cable and also tell if your cable has become waterlogged. You can also characterise a sample of cable (assumed to not be broken, waterlogged, etc.).
Project info at Marcus’ blog.
The Myriad crew has announced the new Stream board released through the MyriadRF initiative for doing SDR with the LMS6002D/LMS7002M from Lime Microsystems. It’s a fully Open Source board with Kicad design files and a fully Open Source OpenRISC SoC for the FPGA:
We are thrilled to announce that the STREAM board is the latest project to join the Myriad-RF family. A feature-packed FPGA development platform built around an Altera Cyclone IV device, this includes RFDIO and FMC connectors, enabling use with the MYRIAD-RF 1 TRANSCEIVER, future modules and other FMC cards.
A version of LMS SUITE is provided for use with the LMS7002M UNITE board, which enables control of the transceiver and spectrum analysis via an FFT viewer, along with example waveforms which can be loaded into the FPGA.
Olof Kindgren has developed an OPENRISC SoC for the STREAM that is capable of running Linux, complete with a peripheral controller for interfacing RFDIO cards such as the Myriad-RF 1. This allows for a mixed development model whereby programming and control can be via the RISC processor, with baseband and digital processing taking place directly in the FPGA fabric.
Project info at Myriadrf.org.
Via the contact form.
Think electronic safes are fail safe? Here’s a video by Jeff Popio, Sr. Security Architect for Stealth Entry LLC, demonstrating an electronic safe fail and highlighting the vulnerabilities of these units.
This talk was presented at the Central Ohio Infosec Summit held last February.
Video courtesy of Irongeek.
