Interesting app note from Analog Devices when an I2C communication is broken under some circumstances. Link here (PDF) The I2C bus is a high integrity, robust serial bus used for control purposes in many systems. The primary components that make up a system are at least one master and one slave. Under normal conditions, everything […]
Author Archives: DP
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: Environmental compensation on the AD7142: The effects of temperature and humidity on capacitance sensors
An old but useful application from Analog Devices about things that can affect touch/capacitance sensors. Link here (PDF) Capacitance sensing has the potential to replace current user input mechanisms in consumer devices. Products as diverse as cell phones, digital cameras, MP3 players, and other portable media players are all suitable for implementing capacitance sensing. Capacitance […]
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 […]
An isolated analog output for Arduino Uno
Giovanni Carrera writes: This project completes the series of my articles about the Arduino analog I/O with the aim to use it as a controller of small automation systems. In control systems of the industrial plants it is always advisable to isolate both the inputs and the outputs coming from the field. This prevents disturbances […]
Binary clock
Frederick Vandenbosch made a binary clock with Raspberry Pi Zero and Unicorn pHAT. He documented the whole process on his blog: At the center of the project are a PiZero and a Unicorn pHAT. The PiZero fetches the time, converts it to binary and controls the Unicorn pHAT with a Python script. The Unicorn pHAT’s […]
A dual sensor fan controller build
Kerry Wong has designed and built a dual sensor fan controller: To make the design more useful, one channel is marked as optional (see components with * on the silkscreen) so that you can build either a single sensor fan controller or a dual sensor one. With two sensors, the control signal is or’d with both […]
Automatic volume tracking for a TV
An automatic volume tracker by KA7OEI: It occurred to me that I did have a reference on which I could base an outboard volume control: The internal speakers of the TV. I surmised that I could “listen” to the audio level coming out of the speakers and based on that, adjust the volume of an outboard amplifier. […]
#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 […]
RC2014/LL and RC2016/10
Scott Lawrence has written an article detailing his Z80 homebuilt computer, the RC2014: The RetroChallenge is upon us again! This time around, I plan on working on my Z80 homebuilt computer, the RC2014. (Website for RC2014, Order a RC2014) For a few months now, I’ve had my RC-2014 computer built, and modified to be an RC2014/LL […]
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: Implementing a line frequency meter
Circuit from Murata about line frequency measurement utilizing Murata’s DMS series digital voltmeters, LM2917 frequency-to-voltage converter and a transformer for isolation. Link here (PDF)
App note: Engineering scaling
Scaling large values to be fed on limited input digital meters, application note from Murata. Link here (PDF) It is oftentimes necessary to attenuate “large” input signals down to a level that more closely matches the input range of a selected meter. For example, suppose the signal to be measured is 19 Volts, and the input […]
Review of NeoDen 4 pick and place machine with vision system
Ray Wang wrote up a review of NeoDen 4 pick and place machine with built-in vision system: Recently NeoDen released a new model called NeoDen 4 — it’s their first desktop model that has built-in computer vision system. The vision-based alignment makes it possible to place fine-pitched components with minimal manual work. It has four pick […]
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 […]
Tutorial: DHT22 sensor with a PICmicro
Gianni Bernardo has published a tutorial for usage of DHT22 sensor with a PICmicro (machine translation). Tutorial about DHT22 / AM2302 Digital Humidity and Temperature sensor usage on picmicro, using XC Compiler. Code is for a PIC12F1822, data from sensor are formatted and sent on UART @9600baud Source code is available on github. Via the contact […]
40 dB attenuator
A 40 dB attenuator project by Hartmut DK5LH. Hartmut uses the attenuator to measure the power of his transmitter (2 watts) with a power meter for -80 dBm to -10 dBm The attenuator is used to reduce the output power of the set to a value that is less than 0.1 milliwatt. (-10 dBm) More details at PA1B’s […]
#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 […]
μPC1237 based 2 channel speaker protector
Dilshan Jayakody has published a new build: When working with expensive speaker system, speaker protector is an essential item to avoid any damages to speakers. In this project we build low cost speaker protector by using NEC’s μPC1237 IC. The circuit in this project is based on μPC1237 datasheet and it is specifically modified to […]
Sonicare toothbrush teardown: microcontroller, H bridge, and inductive charging
Ken Shirriff did a teardown of a Sonicare electric toothbrush: The photos below show the top and bottom of the toothbrush internals. I expected to find a simple, low-cost mechanism, so I was surprised at how much complexity there was inside. The vibration mechanism (right) is built from multiple metal and plastic parts screwed together, requiring […]