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 […]
Author Archives: DP
FPGA-based disk controller for Apple II
Steve Chamberlin over at Big Mess o’Wires has been working on an FPGA-based disk controller for Apple II, which he call Yellowstone: Apple II disk controller cards are weird, there are a crazy number of different types, and many are rare and expensive. Can an FPGA-based solution save the day for retro collectors? You bet! Nearly […]
ESP32lights
Luca Dentella published a new build: Today’s project, ESP32lights, is a smart device based on the esp32 chip. Thanks to ESP32lights you can turn a load on and off (I used it for my christmas lights) manually based on daily schedules based on the light intensity ESP32lights connects to your wifi network, can be configured […]
Common emitter amplifier design tips & shortcuts
Tips & tricks for the common emitter amplifier design by Alan Wolke (aka W2AEW) This video provides some basic design tips and shortcuts for the Common Emitter, Class A, Amplifier. The considerations for selection of the DC Bias point are presented, as well as some tips on how to set/compute the gain for both degenerated and […]
Yet another ARM development tutorial
ARM development tutorial at smdprutser.nl: It has been a while since I wrote about ARM development. I recently made a Black Magic Probe (BMP) clone which acts different then the original. The BMP can source power to the target, but on my version control signal is inverted. Not a big deal, but can give unintentional […]
#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 […]
Easing the pain of SWD on modern DPS:es
Johan Kanflo writes: On newer DPS:es, the SWD connector is a JST-GH (1.25mm spacing that is) which translates to “really tiny”. The annular rings where you need to apply solder and heat for adding wires are even smaller. This is why the OpenDPS SWD Bottle is handy. Add three P50-E2 pogo pins, and connect to […]
Teardown of an opto-isolator
Cross section and analysis of an opto-isolator from Electronupdate. Check out the video after the break.
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 […]
App note: High-Power backup
App note from Murata on application of Electrical double layer capacitors (EDLCs). Link here (PDF) When you consider backup function in your product, Murata’s supercapacitors (also known as EDLCs, Supercaps) are suitable for backup energy device. Murata’s supercapacitors can discharge in high power up to 10A. Therefore they can cover wide range of backup function […]
App note: Lithium Ion Capacitors: An Effective EDLC Replacement
Hybrid capacitor of EDLC and LIB, Lithium Ion capacitors from TAIYO YUDEN offers solution to conventional EDLC lesser characteristics. Link here (PDF) EDLCs were first created in Japan in the 1970s and began appearing in various home appliances in the 1990s. Since the 2000s, they have been used in mobile phones and digital cameras. EDLCs […]
Free PCB coupon via Facebook to 2 random commenters
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 […]
Teardown of a 65W Cree LED bulb
Kerry Wong did a teardown of a 65W Cree LED bulb: Upon removing the glass bulb enclosure, I was a bit surprised to see that only two power LEDs were used in this Cree bulb. Typically, you would see many more lower wattage LEDs put together to achieve higher wattage ratings. The two power LEDs […]
Tiny, isolated USB to Xcvr interface (PTT, Audio, CAT, …)
Mare writes: I will describe here the USB interface between the radio station and the computer which I recently developed and tested. This post is a continuation of the first part, where I described a simple interface for controlling two digital lines using the USB / Serial Converter, where I presented simple interface to control […]
ZeroBoy – A poor man’s retropie “portable”
A nice build log of ZeroBoy portable retropie project, that is available on Github: You know when you see something and it give you instant inspiration and you also see a few ways you would also improve it. The thing I seen was wonky resistor score zero it’s basically a raspberry pi “hat” that has […]
Happy New Year 2018 from Dangerous Prototypes
Happy New Year! Thank you for reading the blog and being part of our community in 2017! We’re looking forward to more open hardware projects, more how-tos, more videos, more free PCBs, and more hacking in 2018.
App note: Capacitor selection guidelines on LDOs
They are different kind of capacitors, selection for one capacitor varies depending on application. A good read app note from Analog Devices. Link here (PDF) Capacitors are underrated. They do not have transistor counts in the billions nor do they use the latest submicron fabrication technology. In the minds of many engineers, a capacitor is […]
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 […]
App note: Linear regulators reverse voltage protection
Various input and output reverse voltage protection method for linear regulators discussed in this app note from ROHM. Link here (PDF) A linear regulator integrated circuit (IC) is a DC-to-DC buck converter system that reduces a DC supply from higher voltage level to a lower voltage level, thus it requires that the input voltage is […]
Bit-banding explained: A key feature of ARM Cortex-M3/M4
Yahya Tawil over at Atadiat wrote in to let us know about a corner-stone feature in ARM Cortex-M3 processors called bit-banding: Writing a portable code is one of the concerns for developers, and while dealing with bit-fields is not standard in all compilers, it is not very advisable to use. When a feature is available […]