Ethan of Protofusion designed and built a stereo vacuum tube amplifier based off of the TubeLab SimpleSE design.
A new successful board with Dirty PCBs
Jechavarria writes, “Here you can find the last board I develop on DirtyPCB. I’m very happy with the results!”
Via the project log forum.
+/-12V dual power supply
A power supply build by Rajkumar of Electronics Lab:
This project is a solution to power up most of devices or projects requiring dual (+/-12V) power supply.
Symmetric +/-12 VDC power supply has been designed for audio applications, can power up microphone pre-amplifier, audio buffers, audio mixer, distributions amplifier, headphone amplifier, VU meter and few o other equipment or projects required dual supply.
SG90 servo controller
Zoltán of PakaHuszar is working on a SG90 servo controller:
The original idea was the following:
TI Launchpad + SG90 servo, connected to a PC via USB port and it can be controlled from there.
#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.
Curious C-beeper
Electronics DIY published a new build, the Curious C-beeper:
Curious C-Beeper is a fun to build little probe that can be used to quickly detect the capacity of capacitors in pF nF range, test their stability with temperature changes, find broken wires, locate wires, trace wires on PCBs, and to locate live wires behind the walls without touching them. The circuit uses three transistors to make a most unusual capacitance beeper probe. When a capacitor is touched to the probe, the probe beeps at a frequency that varies with capacitance. The frequency change is so steep with capacitance that tiny capacitors may be precisely matched or an exact fixed value may be selected to replace a trimmer in a prototype.
Geek Tour: Visit Shenzhen
Shenzhen is the hot geek destination right now. Since the hacker camp last spring, it seems like there are at least 3 hackers roaming the neighborhood at any given moment. Add the constant HAXLR8R classes and you’ve got a great vibe. We put together a wiki page to help plan your trip to Shenzhen. Where to stay, how to get data, what to eat, and how to meet us for a beer.
The first draft is below, the latest version will always be on the wiki.
So you’re coming to Shenzhen? Tickets purchased, about to make the big trip and explore the markets yourself? Maybe a factory tour or two? Here’s some stuff that might make your trip smoother.
Yes, we’d love to hang out in Shenzhen!
There’s always lots of hackers in Shenzhen and you’re welcome to join us for food, drink, foot massage, or KTV.
Your welcome meal choices are:
Temperature data logger using PIC12F683 and DS1820
Rajendra over at Electronics Lab wrote an article on his temperature logger based on a Microchip’s 8-pin microcontroller, PIC12F683:
A data logger is a device that records measurements over time. The measurements could be any physical variable like temperature, pressure, voltage, humidity, etc. This project describes how to build a mini logger that records surrounding temperature values. It has following features:
- Uses just one 8?pin chip, so very compact size circuit
- Temperature range: 0 to +125°C
- Can store up to 254 measurements
- Sampling interval options: 1 sec, 1 min, 10 min
- Reset feature to clear all previous measurements
- Serial transfer of recorded measurements to a PC
- Three tactile switches for user inputs and a LED indicator
Wavetek 907 signal generator teardown
Kerry Wong did a teardown of a Wavetek 907 signal generator:
This Wavetek 907 is absolutely humongous. It has the same width as my HP 5350B but is much deeper (23 in.) and weights around 50 pounds. It was built in 1980 and is clearly showing its age. It was sold as “used” so presumably it was in working condition. But given the physical condition it was in my expectations were pretty low.
Surprisingly enough though, it did power up and its output signal frequency and range were pretty much spot-on assuming my HP 5350B was accurate. Unfortunately, after I left it on for about an hour to warm up, the frequency display on the Wavetek 907 went over range (displays a “1″ regardless of the frequency setting). While it still output a signal, the adjustable frequency range dropped from 6.9 GHz – 11.05 GHz to 6.9 GHz – 7.9 GHz.
uVolume T-32 USB volume & media control update
Another update on µVolume USB volume control project by Rupert Hirst of RunAwayBrainz, we covered it previously:
µVolume T-32 USB Volume Control update, featuring infra red media control
Features:
-Arduino Compatible (Atmel Atmega32u4)
-Manual volume adjustment using the rotary encoder
-(IR) Infra red remote control of volume and multimedia controls
-Apple remote or user defined
-Visual and audible Feedback
-RGB Lighting Customization’s
MakeyMakey from Dirty PCBs
TomKeddie writes:
MaKeyMaKey was a very successful Kickstarter from some smart guys at MIT. It uses capacitive touch to stimulate USB HID devices using a Arduino Leonardo compatible programming environment.
We ran a workshop at VHS in Vancouver Canada in July 2014 building these using PCBs from Dirty PCBs. The design is open hardware, the Eagle files, bootloader and sketches can all be found on github.
I’ve contributed a layout photo, parts list and basic instructions at github.
At HOPE, EFF releases code for Open Wireless router
At last weekend’s HOPE Conference in New York City, the EFF released the code for their experimental hacker alpha wireless router software specifically designed to support secure, shareable Open Wireless networks.
We are offering this hacker alpha release to engage enthusiastic technical users who would like to help us test, develop, improve, and harden the Open Wireless Router. Currently the software runs on one specific model of hardware (the Netgear WNDR3800) and is based on the CeroWRT project. If you have a WNDR3800 router, you can get the developer preview image here and learn how to flash it here. If you’d like to hack on the code base, you can find code and instructions on building it at Github.
Currently the software runs on one specific model of hardware (the Netgear WNDR3800) and is based on the CeroWRT project.
For more info visit the EFF open wireless router page.
Random spottings on factory tour
Joined a friend on a factory audit today totally unrelated to anything electronic. Spotted a few cool thongs though. This is a metal polishing station with a red bull can full of polish.
Down the hall is an unrelated factory making plastic tubing for bag machines. ABS plastic pellets go in the hopper and tube spits out. The single worker running the while factory occasionally measures the output with a ruler.
The tube goes into a bag making machine like this one we spotted at the south China market with Zach Hoeken last week.
Speaking of south China market, that place is strange. Here’s one of a hundred fur shops. Never seen anything like it. No red paint anywhere in sight. More on south China market shortly. Maybe write it up on way back to office from this tour.
Taxi death on way to Shenzhen factory visit
Took a taxi about an hour to the manufacturing area of Shenzhen, Bao’on. When we got in it seemed like there was something wrong with the car or driver, 3rd and 4th gears seemed nonexistent.
Initially I though maybe we should swap cabs, its a long trip after all. But that seemed just too paranoid.
Paranoia in this case was founded. In the middle of nowhere, on a toll road, the car starts to crap out. The driver, unphased, ignored our suggestion to pull over and drove the thing until it died in the middle of the high speed road.
Being a toll road there aren’t any taxis trolling for pickups, and Uber was nowhere to be found. Standing on the shoulder of a Chinese road is terrifying as it became a temporary lane, compensating for the one occupied by the broken taxi. Eventually with enough pleading another taxi came to pick us up.
To his credit the driver added water and oil and got the car going. Didn’t sound like it would make it far though.
In conclusion I leave you with a photo of a Tsing Tao beer adversisment on the toll booth we just past.
ASTROGUN R-Pi based asteroid game
Avishay has developed the ASTROGUN, a Raspberry Pi based asteroid shooting gun and video display system. He originally designed the project along with Maayan Dreamer for the Jerusalem Mini Maker Faire, held last June.
The game is pretty simple – the player stands and has to shoot Asteroids that are coming towards him from any direction, before they hit him. A RADAR-like view helps the player locate the Asteroids around him. The most interesting thing is the display system. We build a HUD – heads up display – which is a display that shows an image overlaid on the background.
More information and source code link is available on Avishay’s blog page.
Via the contact form.
Free PCB Sunday: Pick your PCB
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:
- Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
- Facebook PCB Friday. Free PCBs while you wait for the weekend
- Free PCB Sunday, right here on the blog
- Check out how we mail PCBs worldwide
App note: Design of a low cost, 45W flasher with short circuit protection using LM2902 (Quad Op-Amp) and CSD18534
App note (PDF) on automobile flashers from Texas Instruments
This Application note presents the design of a low cost, flasher circuit with short circuit protection. The design incorporates the entire recommended design feature set for two wheeler flashers and includes low/high voltage operation, half load frequency doubling, and short circuit protection.
App note: Use of MLCC capacitors
App note(PDF) on using Multi-layer ceramic chip(MLCC) capacitors from Altera.
Multi-layer ceramic chip (MLCC) capacitors are used quite often in dc-dc converter input and output filters instead of tantalum or aluminum electrolytics. MLCC’s have low ESR, low ESL, and low cost. They also have no major reliability problems associated with them. All these properties make them suitable for power management applications. There are still, however, some issues to consider when using these capacitors in dc-dc converter circuits. Some ceramic capacitors can lose a lot of their value under certain conditions. This lost capacitance can degrade the transient response of a dc-dc converter, or it can even make the control loop of the converter unstable.
App note: Using the AVR’s High-speed PWM
Atmel’s app note on using the AVR’s High-speed PWM (PDF!):
This application note is an introduction to the use of the high-speed Pulse Width Modulator (PWM) available in some AVR microcontrollers. The assembly code example provided shows how to use the fast PWM in the ATtiny26. The ATtiny15 also features a high-speed PWM timer.
The fast PWM is used to generate a pulse train with varying duty-cycle on the OC1A output pin (PB1). An analog filter can be used to shape the digital PWM output to obtain an analog signal such as a sine wave.
The advantage of high-speed PWM is the increased bandwidth of the analog output signal and that the high frequency allows for smaller and less expensive filter components used to shape the signal.
App note: High voltage, low noise, DC/DC converters
An app note from Linear Technology: High voltage, low noise, DC/DC converters (PDF!)
Photomultipliers (PMT), avalanche photodiodes (APD), ultrasonic transducers, capacitance microphones, radiation detectors and similar devices require high voltage, low current bias. Additionally, the high voltage must be
pristinely free of noise; well under a millivolt is a common
requirement with a few hundred microvolts sometimes
necessary. Normally, switching regulator confi gurations
cannot achieve this performance level without employing
special techniques. One aid to achieving low noise is that
load currents rarely exceed 5mA. This freedom permits
output fi ltering methods that are usually impractical