Here’s how to etch a solderpaste stencil. The process is similar to the UV photo etching method used for DIY PCBs. This is all well and good, but commercial stencils are expensive, and are massive overkill for prototype boards. Here is a method for producing a “good-enough” stencil using aluminium sheet via a method similar […]
Author Archives: DP
What happens when a V-groove hits your copper pour
Panelizing multiple PCBs onto a single panel is a cost effective way of prototyping. V-groves are usually used to separate the different PCBs, making it easy to snap them off. The picture above depicts what happens when the V-grove hits a copper pour such as a ground plane. Anyway, back to the topic. You usually […]
#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 […]
PCB a Week 4: RetroTime
Mats continues his challenge of designing one PCB every week. In week 4 he came up with RetroTime, a digital clock with RGB LEDs in 12 tentacles extruding from the body of the PCB. Next week I’ll do a slightly more advanced project than a simple breakout. I had this idea of making a very […]
Arduino burglary prevention
michu figures thieves rarely enter a house if they think someone is home. You might fool a burgler by leaving on a light or TV when you go out, but what a waste of electricity. This simple Arduino project simulates the lighting of a TV, making it look like it’s on while consuming far less […]
A simple, flexible adjustable dummy load
Nickjohnson posted his flexible dummy load project in the project log forum: I’ve been testing Loki’s power supply lately, and hurting for the lack of a good dummy load. There are plenty of flexible dummy load projects out there, but they’re largely over-engineered and on the expensive side. I decided to put together a really simple […]
Reverse geocaching box
Brian writes: I made a single circuit board version of Arduiniana’s famous “Reverse Geocache” box lately. It is based off a PIC instead of an Arduino and incorporates all of the required electronics into one package, saving money and packaging space. The write-up also has a few good tips about the dangers of multiple power […]
Crystal oscillator frequencies
Drone refers us to this table of Crystal oscillator frequencies from Wikipedia: Wikipedia has a nice table of “Crystal oscillator frequencies”. The table includes a column of crystals divisible by powers of 2 which may be appropriate for Real Time Clock (RTC) references… Xtal frequencies covered in the table (at my post-time) cover 32768KHz through […]
ATX Breakout Board V1.1 Acrylic case V1 back in stock at Seeed
The ATX Breakout Board v1.1 Sick of Beige case is back in stock at Seeed Studio. This case is designed to be simple, cheap, and easy to assemble. The ATX Breakout Board is sandwiched between two laser-cut acrylic sheets, and the whole assembly is held together with aluminum screws and standoffs. This is a minor update […]
ENC424J600 breakout free PCB build
Garyservin built a free ENC424J600 Ethernet breakout board. This is the 100MBPS ethernet chip from Microchip, the fairly recent update to the 10MBPS ENC28J60. If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB […]
App Note: mTouch CVD capacitive sensing method
Here’s an app note from Microchip describing the implementation of the mTouch capacitive voltage divider (CVD) capacitive sensing. CVD is a capacitive sensing technique designed to only require a single ADC pin to function. CVD measures capacitance connected to this pin by comparing it to the internal capacitance of the ADC sample and hold circuit. […]
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: Digital potentiometer in analog applications
Here’s an app note from Maxim describing the use of a digital potentiometer in analog circuits like amplifiers and filters. By using a digital potentiometer in an op-amps feedback loop, a digitally controllable variable gain amplifier is constructed. Variable gain amplifiers often use a mechanical potentiometer to set the gain. An example is a volume […]
App note: Diode turn-on time induced failures in switching regulators
A video from the comments on our post about fast diodes for switching regulators: Recently, switching regulator clock rate and transition time have become faster, making diode turn-on time a critical issue. A potential difficulty due to diode turn-on time is that the resultant transitory “overshoot” voltage across the diode, even when restricted to nanoseconds, […]
App Note: Linear Databook and the two-volume Linear Applications Handbook
Drone tipped us to scanned versions of the Linear Databook, and Linear Applications Handbook (vol.1 and vol.2) available online. These are collections of many app notes produced over the years by Linear Technology. Freely view/download the venerable set of Linear Technology Corporation’s Linear Databook and two-volume Linear Applications Handbook. Free to view online or download […]
Tiny TL-WR703N router acts as a wireless USB port
Madox wrote a tutorial on how to setup the cheap TL-WR703N WiFi router to act as a wireless USB port for your Windows computer. This means that any USB device you attach to the router will be recognized by your own computer as if it was pluged into a local USB port. So it has […]
Tweeting cat door
Let your cats be part of the social media explosion! The tweeting cat door project tweets a message every time a cat passes through the door. The project is based around the Electric Imp which is a Cortex M3 processor and a WiFi transmitter packed into an SD card. A breakout board for the Electric […]
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. More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week: Free PCB Sunday. The classic. Every week, get […]
Week in (p)review January 04, 2013
Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon. Happy 2013 from Dangerous Prototypes No video due to holidays HOW-TO: MYSQL database remote backup script Web Platform scratch and dent on its way to recovery ATX Breakout board and Logic Shrimp v2b free PCB build WordPress reinstall […]
Hacking footprints for easier 2 layer routing
Routing complex surface mount circuits on a 1 or 2 layer PCB is tricky. TSSOP and similar small parts often don’t have enough clearance to route a trace between two leads. Mats tackled this by by removing a few unused leads. This gave him the freedom to route traces through the now available space where […]