idpromnut built a free Bus Pirate v3.8 PCBs. The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff. 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 drawer. Get […]
Author Archives: DP
Using input impedance to measure current
Using input impedance to measure current, see the detailed blog post here from Sigzig: Input impedance on measurement equipment is usually kept as high as it can in an effort to prevent loading down the signals the equipment is measuring. For example most general purpose digital multimeters aim for an input impedance of at least […]
Bus Pirate v3.8 free PCB build
Mark Stewart built two free Bus Pirate v3.8 PCBs. The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff. 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 drawer. […]
A JTAG/XSVF library for Arduino
Marcelo published a post on his blog about JTAG and the library he wrote. I have recently felt the need to incorporate a JTAG port in a project to program a hardware that contained a CPLD. The idea was to both program it and perform some integrity tests on the board. I imagined something using […]
Testing the Shinyei PPD42NS
From the comments on our Arduino dust sensor post, KH writes: The sensor can obviously measure dust concentrations, it also has to be placed and set up properly, and it gives useful readings. For hobby users like most of us, obviously calibration to specific or absolute standards will be almost impossible. More details at Darell […]
#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 […]
50W LM3886 power amplifier
A 50W LM3886 power amplifier project from Electronics-DIY: This is a second revision of 50W LM3886 power amplifier that is used to power two bookshelf speakers. The sound produced by LM3886 chip is excellent so I decided to make another amplifier with it. The schematic is based on the schematic in the datasheet of the […]
Mearm forked
Bajdi’s self designed version of the mearm using 3 stepper motors: Since I was not very happy with the original design I decided to make my own version. Goal was to make it much simpler to print, less pieces that don’t need to be so accurate to fit together. I used freecad to design my […]
Yet another scanning Monochromator build
Kerry D. Wong writes: A while ago, I saw a video on the signal path in which Shahriar modified his Verity EP200Mmd monochromator/detector and turned it into a scanning monochromator. Inspired by his work, I decided to do something similar. Since I do not have the equipment to make the mechanical pieces, I decided to […]
App note: Bi-directional translator architectures
Voltage translation app note from Fairchild Semiconductors, this app note include their auto bi-directional voltage translator that removes the burden of direction control. Link here (PDF) Voltage translators, or “level shifters” as they are sometimes called, allow the coupling of signals that do not share common VCC domains. For example, a signal generated from a […]
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: Reset timers
Reset timers application note from Fairchild Semiconductors. Link here (PDF) As smart phones continually add functionality, it increases the likelihood of device lock up. This condition has been called the “White Screen of Death” which is a new take on the popular phrase used to describe Windows PCs after a system fault. Before the advent […]
App note: Typically testing “Typical” in a typical manner
Typically testing “Typical” in a typical manner, app note here (PDF!) from Maxim: Typical (typ) is typically the most misunderstood word in Integrated Circuit (IC) testing. Typical values can’t be tested directly because they are a statistical value. We discuss how to read a data sheet to understand what parameters are tested and under what […]
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 […]
Geiger counter with SBM20 tube
j3tstream writes: I “rebuild” my Geiger counter, the SBM-20 tube was initially inside the box, i have put this one inside a 32mm diam plastic tube, for more convenience, wired through a XLR3 cable. This counter is from “Electronique-Pratique” n°368, a french electronic magazine. Shem, pcb, and PIC hex & C source code available. More […]
Raspberry Pi garage door controller
As a follow up to yesterday’s Raspberry Pi and ARM uC Breakout + DirtyPCBs mini-review post, hipfan75 has posted the completed Raspberry Pi-based Garage Door controller project: The whole project started after a technician from Urgent Garage Doors pointed out that our two-bay setup had no remote monitoring whatsoever — a gap that felt embarrassing […]
Lowpass filter for 30m
Flathagen made a 30m lowpass filter for his Softrock Ensemble RXTX tranceiver: I just finished a 30m lowpass filter for the Softrock Ensemble RXTX tranceiver. I used the schematic provided by WB5RVZ. L200 and L201 is wound to about 0.9uH, whereas C200 and C202 is 100pF and C201 is 330pF. Everything is soldered to a […]
Arduino dust sensor
Shadowandy’s Arduino-based Dust Sensor project: Put together a dust sensor using Arduino Mega 2560, Shinyei PPD42NS dust sensor and LCD shield. The codes and wiring instructions for Arduino Mega 2560 and Shinyei PPD42NS is as follow. However, I did include Serial output so you can view the sampling results using Arduino IDE’s Serial Monitor (9600 […]
Raspberry Pi and ARM uC Breakout + DirtyPCBs mini-review
hipfan75 writes: Briefly, it’s a Raspberry Pi v1, Model B, Rev2 breakout with an STM32F030 microcontroller connected to the Pi UART, with all GPIOs for both broken out. There are also connectors for an NRF24L01+ module, a 12V boost module, and 315/433 Mhz wireless transmitters. One board will serve as my Garage Door Controller, while […]
ChainringGen – making a chainring with open source software
Rich Olson writes: ChainringGen is an OpenSCAD script I wrote that can generate a bike chainring with any specifications you like. You can download ChainringGen here. You can control parameters like bolt-circle-diameter (BCD), number of bolt holes, number of teeth and other stuff. I primarily created ChainringGen because I thought designing / milling my own […]