Dilshan Jayakody writes: Audio output transformers are heavily used in vacuum tube and some (older) transistor base audio power amplifiers, but these days output transformer are quiet hard to find and expensive item. For homebrew projects the best option is to construct those transformers by ourselves and this script helps to calculate winding parameters […]
Author Archives: DP
ESP8266 firmware flashing with a Bus Pirate
Jonathan Endersby writes, “Flashing the firmware on an ESP8266 is apparently not so straight forward. This is the process I used to get it to work reliably.” Via Hackaday.io Get an assembled Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.
Therm: a Tiny PID controller
A tiny PID controller project from Ethan Zonca: Therm is a very small PID controller with an OLED display, thermocouple interface, and USB port. It can switch an external solid-state relay for driving large loads, or a transistor for driving small loads. When attached to a computer, it enumerates as a USB serial port for […]
Unbrick a Teclast X98 BIOS with Bus Pirate 4 and Flashrom
cosmok82 has posted a tutorial on how to unbrick a Teclast X98 BIOS with Bus Pirate 4 and Flashrom: Sometimes you put your feet out of bed and a bad day comes. In all these days C/D is close to you! Enjoy our guide, step by step to unbrick your Teclast X98 tablet. First of all. […]
Simple scalar network analyzer
rheslip blogged about his simple scalar network analyzer project: The principle is to stimulate an electrical network with a sinewave and measure the magnitude of the response. If we sweep over a range of frequencies and measure the power transmitted through the network we can determine its frequency response. Transfer from the input port (1) […]
#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 […]
Teensy GPS Logger redesigned in smaller version
An update on J3tstream’s Teensy GPS logger project we covered previously: The last and final design, the Teensy and GPS is directly powered from 3.7v li-on batt. Power button in red, black button to enable charging in case of using +5v AC adapter. SDCard socket is mounted at the back of pcb. Project info at […]
Tutorial: Using GNU profiling (gprof) with ARM Cortex-M
Erich Styger of MCUonEclipse writes, “I have published a Sneak Preview how GNU gprof profiling looks for an embedded target ARM Cortex-M in an earlier post. This tutorial explains how to profile an embedded application (no RTOS needed) on ARM Cortex-M devices with GNU gprof. Additionally I explain the inner workings to generate the data […]
Free energy & over-unity charging circuit – The scientific method
In this episode Shahriar builds a magical charger circuit that has an efficiency of tens-of-thousands of percent! But not to worry, it is a trick and the trick is revealed in the video. The purpose of the video is to discuss the nature of the scientific method and our society’s need for free education. Via […]
An Android reflow controller that anyone can build
Andy Brown published a new build, an Android reflow controller: The only surface mount device on this PCB is the MAX31855 and it has a low number of generously spaced pins. I eschewed my hot air gun, previous reflow oven and hot plate in favour of a plain old iron and the tack-soldering method because […]
App note: Overview of USB battery charging revision 1.2 and the important role of charger detectors
Ever wonder why USB connector’s power are longer than the D+ D- pads? Here’s an app note from Maxim Integrated about these detection proccess and their importance. Link here (PDF) This application note explains details of the USB Battery Charging Specification 1.2, and the role of charger detection. With the use of charger detection ICs, […]
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: Get a constant +5V output by switching between a +5V input and a single-cell LI+ rechargeable cell
App note from Maxim Integrated on providing smooth power from two sources. Link here (PDF) Design provides a simple method for maintaining an uninterrupted +5V even while switching between the external +5V supply and a rechargeable single-cell Li+ battery.
App note: Low drop fixed and adjustable positive voltage regulators
Low drop fixed and adjustable positive voltage regulators application note (PDF!) from ST: The LD1117A is a low drop voltage regulator able to provide up to 1 A of output current, available also in adjustable versions (VREF = 1.25 V). In fixed versions, the following output voltages are offered: 1.2 V, 1.8V, and 3.3 V. The […]
Sturdy pots on breadboards
Paul over at DorkbotPDX writes, “Often I throw together a quick demo for the bi-weekly DorkbotPDX meetup, usually involving one or more pots to adjust parameters. Finally, I’ve come up with a pretty good way to put pots on solderless breadboards.” More details at Paul’s blog. Check out the video after the break.
Windows 10 IoT core controlling a Raspberry Pi 2 robot
Windows 10 IoT Core running a Raspberry Pi 2 robot by Scott Hanselman: Starting with a Raspberry Pi 2, walk through the setup instructions here. You do need to have a Windows 10 today to installing Windows 10 IoT Core but at least it’s gotten a lot easier with the latest build for IOT. There’s […]
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 […]
Simple pendulum tiltmeter
Jbeale shared his tiltmeter project in the forum: Apparently the most popular sensor for this purpose is an “electrolytic tilt sensor”, basically a bubble level with internal electrodes. These are not exactly consumer items. I tried building a simple pendulum tiltmeter using a split-photodiode, Optek OPR2100 (about $10 from Mouser) and LF411 opamp. The pendulum […]
Are my documents safe in the root cellar at ~80% humidity?
luckyresistor has been working on his Data Logger project: There is a large cellar where I could store unused items and documents, but the catch is the humidity there. It is a root cellar near a small brook and the humidity varies between 75% up to 90%. Archived material should never be exposed to humidity […]
MQTT/JQUERY/WebSockets controller
Peter Scargill writes: I wrote a while ago about using web sockets as against something like NETIO for controlling the home – most folk liked the article but I think part of it was a little complicated – and at the time I’d not really thought it out to make it as simple as possible. […]