DIY MechBoard64 @ breadbox64.com: When the MechBoard64 was finally realized and presented on my blog, it soon came clear that a new mechanical keyboard was the missing piece in the creation of a brand new Commodore 64 (…well that and some new keycaps…). As I have no intention to become a Commodore 64 mechanical keyboard […]
Author Archives: DP
#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 […]
Shirt-pocket SSB transceiver
Peter (DK7IH) blogged about his 14MHz shirt-pocket SSB transceiver.
How to correctly set the motor current limit on an A4988 stepper motor driver
Michael posted detailed instructions of how to set up your A4988 stepper motor driver’s motor current limit: One important thing to set up when using these drivers is the motor current limit. This is especially important when you’re using a higher input voltage than what the motor is rated for. Using a higher voltage generally […]
App note: Guidelines on the effects of parasitic capacitance on clock accuracy due to board layout
Board design considerations like board thickness and layer stacking under a crystal when designing PCB for accurate clock crystals discuss in this app note from Maxim Integrated. Link here Crystal oscillator is widely used in RTC applications. Clock accuracy, one of the key parameters in real-time clocks, partly depends on the parasitic capacitance of the […]
App note: Basics of ventilator systems
App note from Maxim Integrated about the design of modern ventilator system. Link here This application note provides an overview of ventilator systems with a focus on system design for precision measurement and reliable protection. It discusses the four key components of a pneumatic ventilation system: gas supply, gas flow mixture, inhalation and exhalation systems. […]
Reverse-engineering and comparing two Game Boy audio amplifier chips
Reverse-engineering and comparing two game boy audio amplifier chips @ righto.com The Nintendo Game Boy contains an audio amplifier chip for sound through a speaker or headphones. In this post, I reverse-engineer this chip and compare it with the later Game Boy Color chip (reverse-engineered earlier). Unexpectedly the Game Boy Color uses an entirely different […]
Open IP over VHF/UHF
David @ Rowetel writes, “My initial goal for this work is a “100 kbit/s IP link” for VHF/UHF using Codec 2 modems and SDR. One application is moving Ham Radio data past the 1995-era “9600 bits/s data port” paradigm to real time IP.” See the full post at rowetel.com.
Building a chaotic oscillator from common components
cpldcpu writes: A chaotic oscillator is an electronic circuit that can exhibit “chaotic“, nonperiodic behavior. A commonly cited example is Chua’s circuit, but there are many others. I always regarded these as carefully designed, rather academic, examples. So I was a bit surprised to observe apparently chaotic behavior in a completely unrelated experiment. See the […]
HDSP clock with SCD5583 display
FlorinC’s HDSP clock with SCD5583 display: Here is another interesting “intelligent” LED matrix display, whose name actually makes some sense (unlike HDSP-2354, among many others): SCD5583A. I reckon it means: “Serial Character Display with 5x5x8 dot matrix”. 3 is the code is for green (0 for red, 1 for yellow). More details on Wise time […]
Lightdriver
Drive WS2812B LED strips from a PMOD device, a lightdriver project @ anfractuosity.com: I created a PMOD module PCB using KiCAD, that enables connecting WS2812B lighting strips to an FPGA board with a PMOD interface. The board was assembled by JLCPCB. This is my first project using an FPGA, I plan to soon implement an […]
App note: 48V buck converter helps MHEVs meet fuel emission standards
Maxim Integrated got you covered on designing all in 48V automotive compliant buck converter. Link here Ever-tightening automotive fuel emission standards are becoming challenging. The gasoline engine needs the help of an electric motor to meet these standards, leading to the introduction of mild hybrid electric vehicles (MHEV) with higher battery voltages. 48V hybrids are […]
App note: Surge-proof your industrial sensor
Design solution for a robust and reliable power supply for industrial sensors from Maxim Integrated. Link here Modern industrial sensors must operate reliably in harsh and demanding industrial environments where they are prone to large surge voltages and mechanical stresses. This places considerable demands on the DC power supply that they use. We consider the […]
Automatic keyboard switch tester
James made this automatic keyboard switch tester, that is available on GitHub: It uses a servo to turn a robotic finger that slowly presses the switch down. When it detects that the switch has closed, it lights up the LED and waits 100 ms for the contacts to settle, before slowly releasing the switch until […]
Low cost Carbon Monoxide meter
Dilshan has published a new build: Today Carbon Monoxide (CO) meters are available in different forms. Overall, Carbon Monoxide meters sense CO fast and display the amount to the user and trigger alarm if it reaches a critical level. Compare with most of the DIY Carbon Monoxide meters, the project which we described in this […]
App note: RC Snubber for Class-D audio amplifiers
App note from Cirrus about overshoot/ringing suppression in the output stage of Class-D amplifiers using RC Snubber. Link here (PDF) High speed switching of power MOSFETs in the power stage of Class-D amplifiers results in output voltage over/undershoot and high frequency ringing on the output waveform. The over/undershoot places additional stress on the power MOSFETs, […]
A full-duplex tiny AVR software UART
Nerd Ralph writes: I’ve written a few software UARTs for AVR MCUs. All of them have bit-banged the output, using cycle-counted assembler busy loops to time the output of each bit. The code requires interrupts to be disabled to ensure accurate timing between bits. This makes it impossible to receive data at the same time […]
Using the ADS1115 in continuous mode for burst sampling
Edward Mallon writes, “The 16-bit ADS1115 has a programmable amplifier at the front end, where the highest gain setting providing a range of +/- 0.256 v and a resolution of about 8 micro volts. But readers of this blog know you can already approach 14-16 bit sensitivity levels with Arduino’s ADC by oversampling with lower […]
#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 […]
An ESP8266-based temperature, humidity and line voltage monitor
KA7OEI’s temperature/humidity/line voltage web server/telemetering device: As anyone who reads this blog probably knows, I have a bit to do with the operation and maintenance of the Northern Utah WebSDR – a remote receiver system that allows anyone with Internet access and a web browser to listen to the LF, MF, HF and some of […]