Rupert Hirst has written a detailed article on his AVR V-USB media volume control: My most rewarding projects are the ones which i actually use. I like my audio gear so, this was the perfect companion project! On my desk i have a headphone amplifier for my AKG K702’s headphones, below it i have my self built […]
Author Archives: DP
A self-powered battery tester with an EFM32
A self-powered battery tester with an EFM32 by Hlipka: So the idea that came to my mind was: why not build a proper battery meter which can give real and accurate numbers. That can’t be so complicated! And since the EFM32 is so low-power, why not make it powered from the battery I’m currently measuring? Drawing […]
Precision temperature measurement
Scott Harden writes: In an effort to resume previous work [A, B, C, D] on developing a crystal oven for radio frequency transmitter / receiver stabilization purposes, the first step for me was to create a device to accurately measure and log temperature. Check out the video after the break.
AVR Atmega dehumidifier controller board update
Davide Gironi posted an update on his AVR Atmega dehumidifier controller board we covered previously: The main issue that i’ve fixed is the microcontroller crash, that happens sometimes. I’ve noticed that sometimes the controller stop running, crash or doesn’t works as expected. After some experimets, i’ve noticed that probem was due to Electromagnetic Interference (EMI), EMI […]
Tips and tricks using the 24LC256 I2C EEPROM memories
Jechavarria shared some tips and tricks on using the 24LC256 I2C EEPROM memories: I resume this brief series of articles with another device I usually use. It’s the popular 24LC256 I2C EEPROM memory, from Microchip. First of all, you can find the datasheet here. This memory has a 32K x 8 bytes of capacity (36768 bytes if you […]
DIY HP/Agilent 53131A 010 high stability timebase option
Gerry Sweeney wrote a post on his blog detailing his DIY HP/Agilent 53131A 010 high stability timebase option: I decided to make a clone 010 option board for my counter using a second-hand OCXO bought from e-bay. I designed a PCB to get a professional finish as well as a reliable upgrade for my counter. The main […]
555 timer chip scroll music player
Here’s a music player project based on 555 timer chip by RimstarOrg: This is a music player I made for my entry for the 2013 Ottawa Mini-Maker Faire. It’s based on the popular 555 timer chip. My main design criteria was that it had to be far more robust than my previous music player that used […]
Yet another semiconductor V/I curve tracer – II
Kerry D. Wong posted an update on his semiconductor V/I curve tracer we covered previously: In my previous post, I showed my design of a semiconductor V/I curve tracer and discussed its theory of operation in detail. As promised, I will share some of the test results here. If you have not read my previous article, […]
Bringing OpenWRT to TL-WA801ND v2 (Part 2, building OpenWRT)
TasksOfOhm has posted a detailed tutorial on building OpenWRT on TL-WA801ND v2 : After getting some details about the board it was time to create a build environment. In my case this was just about copying one of the VMs I have prepared just for this purpose. The build environment requires a Linux machine whereas it doesn’t […]
#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 […]
A mini microphone preamplifier
Boris Landoni from Open Electronics has written an article about the design of a microphone preamplifier: This Mini Microphone Preamplifier could be used as the first stage to amplify any audio signal. The device is equipped with a microphone plus clips to be connected to a 9V battery. Amplification is achieved by using an operational LM741 amplifier. […]
DIY Atmel AVR Dragon case
Systemstech designed this case for his Atmel AVR Dragon. Via the forum.
Monitoring room temperature using Arduino
Dobrica wrote a post on his blog detailing the build of his simple temperature monitor using Arduino Nano: For a last few months, I have been playing around with Arduino and collecting useful parts for my first real project. Last week we purchased Mitsubishi air condition with super-invertor and I wasn’t totally happy with the way it operated so […]
3V-5V switchable I2C Real Time Clock Shield
Dave writes: Using the Maxim/Dallas 1307 RTC that runs at 5V with the Arduino Due that runs at 3V. FETs are used for bidirectional level shifter per a Philips app note. All built on a Freetronics ProtoShield of course! Via the forum.
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: Advantages of IC-based hot-swap circuit protection
Here’s an application note from Maxim describing hot-swap circuits, and the advantages of dedicated hot-swap ICs over discrete component circuits: There are many approaches for protecting a system against electrostatic discharge (ESD), surge current, overcurrent, undervoltage, overvoltage, and other disruptions to power. Industry, company, or regulatory standards such as UL®, USB, IEEE®, CSA, or IEC […]
App note: Regulator topologies for battery-powered systems
Here is an app note from Maxim describing the various SMPS regulator topologies for battery powered systems: This tutorial presents an overview of regulator topologies for battery-powered equipment. The discussion covers linear regulators, charge pumps, buck and boost regulators, inverters, and flyback designs. The importance of peak current is explained, and schematics of each topology […]
Bipolar stepper motor driver circuit with LMD18245
Viktor blogged about his bipolar stepper motor driver based on Texas Instuments’ LMD18245 build: After extensive research on the internet I decided to make a bipolar stepper motor driver based on Texas Instuments’ LMD18245, which is a 3A, 55V DMOS Full-Bridge Motor Driver. It incorporates all the circuit blocks required to drive and control current in a […]
Giveaway: TraId kits – Transistor type & pinout identifier
Mats has amazed us with his board a week projects, and now one of them could be yours! Today Mats is giving away three TraId kits – Transistor type & pinout identifier. All parts included except for a CR2032 battery that needs to be sourced locally due to postage regulations: TraId is a really low cost […]
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 […]