Modified Heathkit HD-1410 electronic keyer

27208651132_5845db63e2_z-600

Dilshan Jayakody writes:

HD-1410 is quiet popular iambic keyer which is manufactured around 1970’s by Heathkit. The original HD-1410 keyer is designed using 5 commonly available 74LS series TTL ICs and 8 transistors. Other than iambic operation it has an option to adjust sidetone frequency and support for (external) single-paddle key unit.
In this project we redesign original HD-1410 electronic keyer with today’s commonly available components. In this new design the key components which we replace are transistors, diodes and power supply section of original HD-1410 circuit. Most of the NPN transistors in original design are replaced with KSP42 and KSP10 transistors, and all the PNP transistors are replaced with KSP92 transistors. To keep everything simple we also use same TTL chip-set with this new design.

More details at Jayakody’s blog. Project files are available at elect.wikispaces.com.

USB to RS485

pcb-assembled-600

Marko Pavlin has published a new build:

Testing of sensors with RS485 using PC without proper interface is not possible. Since RS232 interfaces are very rare, the interface should be hooked to USB. The interface between USB and RS485 can be soldered with one of the many FTDI interfaces with added RS485 driver, or bought as assembled module. There is always the third option. I made it from scratch.

Full details at Mare & Gal Electronics homepage. This project is hosted on GitHub.

Bus Pirate v3.8 free PCB build

BP-build

Ben built a free Bus Pirate v3.8 PCB.  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 your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

App note: Press-Fit technology

an_wurth_elektronik_Power_Elements2

PCB Power connection solution from Würth Elektronik, Link here

As a solder free fastening technology, press-fit technology frequently offers an attractive alternative to simple soldering technology. An effective electrical press-fit connection is created by pressing a pin into the plated through hole of a circuit board and – as part of cold welding process – generating a gas-tight electrical connection.

The trough-hole plating for a press-fit system is essentially made in the same way as are the holes for accepting components for THT soldering. Thus there are no changes required in the pcb manufacturing process. One outstanding characteristic of the press-fit system compared to the soldering system is that it produces not only an electrical connection but also an extraordinarily strong mechanical connection between the inserted components and the PCB.

Free PCB Sunday: Pick your PCB

IRToy 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 get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Going wireless with magnetic shielding

Efficient magnetic shielding application note from Würth Elektronik, Link here (PDF)

Magnetic Field Interferences are increasing in electronic devices due to a number of factors including reduced separation distances of PCB’s, Integrated Circuits and many other sensitive components. In addition to this the extended use of magnetically coupled communication technologies (Qi-WPC, NFC, RFID, PMA, A4WP, WCT…) leads to more complex layout and proximity considerations.

With Ferrite materials it is possible to manage and predict magnetic flux flow and thereby improve efficiency of power transfers, increase distances of near field communications and of course avoid additional unwanted coupling effects which could lead to losses or noise.

Free PCB coupon via Facebook to 2 random commenters

BP

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 times every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

A small collection of NodeMCU Lua scripts

REM_Cycles_m

Limpkin writes:

I usually never use libraries… but made an exception for these quick projects !
I’m pretty sure that most people reading this very article know about the (very) cheap ESP8266 Wifi module.
A bit more than a year ago, I actually made a small development board for it, which was recently used in the connected lamp that wakes me up. While what follows pales in comparison to what cnlohr has implemented on this chip over the last months, sometimes you just have small projects that you don’t want to spent days on.
Anyway, the ‘standard’ way of compiling programs for this neat little chip involves installing a cross-compiling toolchain on a Linux computer (or VM), and then using a dedicated tool to flash your program to the ESP8266.
As you can guess, this can quickly get tiring if all you want to do is blink an LED… but then I stumbled upon NodeMCU and Domoticz.

Full details at Limpkin’s blog.

AVO DA116 repair: Replacing the LCD

 

lcd_new_with_card_and_cover-600

Daniel Bailey from Bit Of A Hack did a repair of a digital Avometer DA116 and documented the whole process on his blog:

Anyway, this post is about my AVO DA116. I did this repair a while ago and almost forgot to post about it. I bought a broken AVO DA116 from ebay. For those who don’t know; AVO made a few digital multimeters before the name AVO went away. So far I have three digital AVOs. I now have two of them fully working, the other uses nixie tubes and still needs fixing.

Full details at Bit Of A Hack site.

Touchpad as wireless (MIDI) expression controller

2013-06-27_00-25-57-600

Acidbourbon has published a new build, a wireless touchpad that can be used like an expression pedal:

This sort of touchpad speaks some special Apple mouse protocol. Luckily I found a code snippet on mikrocontroller.net which helped a great deal to get the thing going.
Then I used a standard AVR ATMega8 microcontroller to glue the transmitter and the touchpad together. That means, I poll the status/position change from the touchpad and if some swiping action was detected, the relative change of coordinates is sent via the radio.
I designed a compact double sided PCB housing both the microcontroller and the radio. It also features a 5V voltage regulator for the microcontroller and the power supply of the touchpad, as well as a 3.3V regulator for supplying the radio.
The touchpad is then connected to one of the free GPIO pins of the microcontroller which are accessible via dedicated pin headers

Project info at Acidbourbon homepage.

Check out the video after the break. Continue reading “Touchpad as wireless (MIDI) expression controller”

RC snubber calculator spreadsheet

ss1

Paulo has developed a free RC snubber calculator, an Excel-based calculator eases the design of RC snubbers in power switching applications:

In power switching applications, a designer often has to contend with spurious oscillations. These are the result of parasitic capacitances and inductance on the board and behave like the step response of an RLC circuit. These transients can induced undesired noise in neighboring circuits and create over voltage spikes that can compromise long term component reliability.
The most common way to mitigate the effects of these transients is by using an RC snubber circuit. There are many excellent sources on the web discussing this topic so I won’t repeat the discussion here (see references below for more information). Instead, I’m offering an Excel-based calculator that simplifies the components selection should you be faced with this task.

More details at paulorenato.com.

Linux alarm clock

alarm-clock

Benoit Frigon wrote an article detailing his alarm clock running Linux project, that is available on github:

This is the display i made for my alarm clock project. The first version was a 24×7 LED matrix but later changed the design for a four digits seven segment display. I decided to keep the drawings for the LED matrix and named it model A and Model B for the segment display.
The display is encapsulated in clear casting epoxy and is 5 inches wide by 2 ¼ inches high by 1 inch thick.

More details at Benoit Frigon’s project page.

A new transceiver at N6QW, part 2

20160524_151211-600

Pete Juliano, N6QW, has been working on a transceiver project. He writes:

Today we complete most of the mechanical work and the only item remaining is the RC Filter to turn the Square Waves into Sine Waves for the tune signal. We have had it on the air in the current box as you always worry that even though it worked on the bench there is always a danger it won’t work in the box.
This rig has a lot of soul as some of the boards were used in the 30M CW transceiver and then moved over to the LBS on the bread board and now this radio. The main tuning knob was purchased in St Louis some 20 years ago and now is now controlling the encoder.
Just in case you are wondering this is not a BITX design but does use bilateral amplifiers originally designed by Plessey. The driver stage is from EMRFD and the intermediate bi-directional amp is my own design as is the 40M Band Pass Filter and the microphone amp. The Low Pass Filter is from W3NQN.

Project info at N6QW blog.

#FreePCB via Twitter to 2 random RTs

BP-600x373

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 it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

Pen FM transmitter bug

pen-fm-transmitter-bug

A pen FM transmitter bug project from Talking Electronics:

Pen FM Transmitter bug projects have been very popular. The idea of being able to hide a transmitter in a pen is very appealing. In an effort to reduce the size of this design, we have used surface-mount components. Firstly, the thought of using the coil in the tank circuit for transmitting RF was a little far fetched, but we used it as an example for those who were interested in experimenting with our circuits. Now we have gone back to a conventional antenna, the whip. The whip or straight-line antenna can be coiled, wound longitudinally or folded. The way it is wound makes a big difference to its effectiveness, but when you are limited in space, you have to accept these limitations. Even though we have used this antenna set up in our previous pen bugs we have considerably improved the circuit to the point were it has low battery consumption, but high RF output. The size of this design has been reduced considerably by using surface-mount components.

More details at Talking Electronics project page.

Ambient TV lighting, a low-power solution for creating ambient light based on a TV signal

system-zoom-600

Here’s an ambient TV lighting project by Shiva Rajagopal from Cornell University, built as a final project:

Here’s a project I recently made for the ECE 5760 FPGA class at Cornell University. I have created a real-time system that can use an NTSC video signal to simulate the lighting effects of a TV in a low-power fashion. This enables such applications as real-time ambient TV lighting, as well as simulating a TV’s light in an unoccupied home to give the appearance of an occupied home. For this to be believable, the system must be able to keep up with the flickering and update speed of a TV signal, and therefore requires a dedicated, real-time processor. The goal of this project was to create a general purpose algorithm that can accomplish this task, and use PWM outputs to drive a larger circuit that controls an RGB LED for verification. The user can send in any NTSC video signal and see the immediate changes on the LED as the video’s dominant color changes.

Full details at Cornell’s ECE5760 Final project page. To optimize your home entertainment, you may seek the Best IPTV services.

Via the contact form.

Check out the video after the break. Continue reading “Ambient TV lighting, a low-power solution for creating ambient light based on a TV signal”

Development board for PIC16F1938

PIC16F1938_1-600

Raj over at Embedded Lab has designed a development board for PIC16F1938:

The PIC16F1938 is a versatile 28-pin MCU belonging to Microchip’s extreme low power microcontroller family featuring nanoWatt XLP technology, 28KB of programming memory, 1KB of RAM, 11 ADC channels, and tons of other peripherals. A while ago, I designed a development board for this MCU and I thought it would be worth sharing this design here. The development board features an onboard USB-UART bridge to support the ds30 Loader for easy programming of the PIC MCU. All I/O pins are accessible through 2×5 headers.

Project info at Embedded Lab site.

App note: Anti-tampering solution for E-Meter application

an_infineon_3D-Magnetic-Sensor-EMeter

App note from Infineon Technologies on 3D sensor used as anti-tampering devices on E-Meters, Link here (PDF)

This application note describes a possible realization of an anti-tampering solution in an Electricity Meter. With the new product family of the 3D Magnetic Sensor (TLV493D), Infineon offers an innovative solution for three-dimensional magnetic position sensing. By allowing a measurement of all three components of a magnetic field at the same time, it enables a multitude of applications with different ranges. Furthermore the integrated temperature sensor enables the application to compensate possible temperature-dependent magnetic field changes.

Free PCB Sunday: Pick your PCB

IRToy 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 get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Using a magnetic 3D sensor in a gear stick application

ap_infineon_How-to-use-3D-sensor

6 hall effect sensors effectively replaced by one 3D sensor, an application from Infineon Technologies. Link here (PDF)

A magnetic 3D sensor is well suitable for a detection of the position of the gear stick. The „State-of-the-art“ solution with up to 6 single hall switches can be replaced by one 3D sensor. The TLE493D-W1B6 has the same package dimensions as a hall switch and leads to cost and space savings.