Tag Archives: Arduino-Raspberry Pi

Home Brew Your Own Arduino UNO

The first question you may ask is, Why would I want to build my own Arduino UNO?  Economically speaking it does not add up in your favor after you acquire the parts and consider the time it takes to put it all together.  This is especially true when you consider that a Nano “clone” could be purchased for around $3!  You might have a permanent use application that makes building one your best option?  Maybe you just like to learn and do stuff just because you can!

The unit below is built on a prototype shield that has become the main board.  For my keyer application I have no need of USB communications and I can keep the wiring down to only what is needed.  The 5v regulator will soon have a small heatsink as it gets warmer than I would like.

Below is the other side of this board.  I used #4-40 screws as “legs”.

Instructions for building one yourself on a solderless breadboard can be found at https://www.arduino.cc/en/Main/Standalone

Instructions on burning the bootloader with another arduino can be found at

https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard

and

https://www.arduino.cc/en/Tutorial/ArduinoISP

If you run into trouble like I did by getting the “wrong” ATmega328 microcontroller you can get work around instructions at http://www.crash-bang.com/resource/bootload-atmega328/

73,

Mike AB1YK

Amateur Radio Day at MakeIt Labs

We will be holding an amateur radio day at MakeIt Labs in Nashua. We are hoping to generate STEM interest among young people by demonstrating all the scientific and engineering principles at work in amateur radio. Participation is welcomed from all club members and folks in the community and we urge you to bring your families, friends, and especially kids showing an interesting in science, engineering, and mathematics. Among our activites, we will:

  1. Set-up a High-frequency (HF) Get-On-The-Air (GOTA) station allowing kids to make contacts (QSO’s) all over the country and potentially the world. We will highlight the interconnectivity among the components to describe how we actually make contacts and showcase the latest and greatest hardware that is on the market. Additionally, we will use VHF/UHF radios to make local contacts which also demonstrates a HAM’s use of amateur radio repeaters to allow extended coverage.
  2. Displays of satellite station set-ups which allow communication with amateur satellites in Low-Earth orbit (allowing beyond-line-of-sight communication), as well as Digital Amateur TV stations which rely on modern maker-based systems such as a Raspberry Pi. Though we will not activate our satellite station (due to weather conditions) we will take interested parties through how the station is constructed, how we find satellites, and what antennas / additional hardware will be needed to make contacts.
  3. Advertise our High-Altitude Balloon Project that can be found on our website. With the information we currently have in tow, we hope to engender a massive amount of interest and excitement among kids and hope that this will serve as an enriching learning experience that they can also bring to their own classrooms. We emphasize modeling, construction, logistics, and post-data analysis in order to lead the kids through what it takes to perform a real-world science experiment!

Amateur Radio at MakeIt Labs

On Saturday, January 28th the Nashua Area Radio Club (Nashua ARC) will be hosting a special event for Interested kids, parents, and friends in the community about the joy of amateur radio at MakeIt Labs in Nashua from 9:00 am – 3:00 pm. You may drop in at any time and stay as long as you like to participate! Among our activities, you can:

Get-On-The-Air Station (GOTA)

This is amateur radio at its best and what it’s known for! We invite you to get on the air and make a contact (we call them QSO’s — pronounced: cue-so) somewhere in the world! You might be able to make a new friend in Germany or even Japan! Making contacts sits at the heart of amateur radio and is an activity that brings people together. So don’t be shy, step up, and hit the push-to-talk button!

Satellite Station Display

The Radio Amateur Satellite Corporation (AMSAT) began in 1969 to foster amateur radio participation in space research and communication. Currently, AMSAT groups help advance the state of the art in space science, space education, and space technology. Come learn about what components go into constructing a station capable of contacting a satellite and what antennas, and smart phone apps, operators use to keep a pulse on the satellite location.

Digital Amateur Television (DATV)

DATV Transceiver RackNot only are amateur radio operators granted privileges to transmit speech, but we also can send fast-scan data such as TV signals! Many operators have experimented with how to homebrew their own fast-scan TV stations, and our club president Fred (AB1OC) and our member Skip (K1NKR) have chosen to use construct a station which uses a Raspberry Pi (RPi) with an Arduino shield to sit at the heart of the transceiver. The RPi is the brains of the TV which runs Linux and among other things is responsible for sequencing, transmit / receive control, automatic VSWR monitoring, and a touch-screen controlling interface to configure and operate the system. Learn about what it takes to build and operate one of these stations. We may even be able to make a contact! More information can be found at https://stationproject.wordpress.com/category/amateur-television/.

Kit Building with Nashua ARC

The Nashua ARC holds kit-building nights where both inexperienced and experienced members homebrew in a relaxed, learning environment. In the past we have built Pixie QRP (low-wattage) kits transmitting Morse Code on the 40m amateur band. But, on February 18 from 1 – 5pm, First Church in Nashua, Nauss Hall, we will build the digital oscilloscope kit DSO138 (shown to left). This kit comes with a clear acrylic case to protect it, build instructions, and among its specs has a 1 Msps sampling rate, 12 bit accuracy, 200 kHz bandwidth (good for audio signals), capable of freezing the waveform display, and comes with a 1Hz / 3.3V test source. We invite you to join us and will bring some kits with us. More info can be found on our website at http://n1fd.org/2016/03/27/inexpensive-diy-digital-oscilloscope-kit/.

We hope you will join us for our event! Please bring friends, family, but most importantly we want you to have fun and enjoy this hobby with us!!

Contact Information

Brian Smigielski (AB1ZO): bsmigs@gmail.com
Jamey Finchum (KC1ENX): jamey@finchum.net

First Homebrew Contact on my Scratch Built BitX 20 SSB Transceiver

About a year ago I decided to build a SSB transceiver for making contacts with other amature radio operators on the HF bands.  I was given good advice from both Bill and Pete from the SolderSmoke Podcast  to start out with a direct conversion receiver then go with the BitX as a fist SSB rig.  I am very happy that they gave me that advice and I would agree that the BitX is not a good first project.

After getting all the proper adjustments made and confirming proper operation with a dummy load it was time to put this rig on the air (I don’t need a case)!   I tried calling CQ using SSB voice but no one came back.  I then decided to add some relays and other modifications to allow digital modes.

On January 15, 2017 at 21:46z I answered a psk31 CQ from Josh K1JOG in Kissimmee, FL.  Little did he know that he would be making history (maybe just for me) in my first home brew QSO.  Below is his eQSL card to me.

Thank you Josh K1JOG for the contact!

If you are interested in scratch building this rig you can follow the photo link  below:

BitX by Ashhar Farhan, VU2ESE

Ashhar Farhan also sells a BitX-40 at http://www.hfsigs.com/

The units he has built in India are almost ready to put on the air.  You build the case / box or just go open board style!  You can’t beat the $59 price for a rig!

Below are some photos of my project:

Mic amp on the left LM386 audio amp on the right

A good place to start is the Audio “end”.  I built mine using perf prototype board.  FYI the 10k ohm resistor on the mic amp needs to be 39k ohm for proper bias.

Balanced Modulator
Balanced Modulator

On the balanced modulator, I used a mystery toroid core because I have a bunch of them and they did not cost much!

10 MHz crystal filter

In this photo you can see some transmit and receive amplifiers and the crystal filter.  I built some test equipment and used a frequency counter to make a matched set of crystals.

Mixer circuit

The mixer circuit is shown here with some coax to the left that is from the VFO.

Original VFO design on the left. Filtered SI5351 clock generator on the right

You can see the benefit of building small modules.  With SMA connectors, I can quickly swap out the VFO “soul” of this rig!  No more drift with the SI5351 chip! I ordered mine from Adafruit. I added a small LC filter to the output to make a nice sine wave.  I am not sure it is needed.

Band Pass Filter by Pete N6QW

Now I had trouble with the original band pass filter.  I’m not sure why but a quick google search on 20m band pass filter and I found a replacement circuit on his website.  When I told Pete about this he sent me a new updated design to try.  My PTT relays are 5v so the small heatsink is for a voltage regulator.  I also included diode protection for the replays.

Irf510 power amplifier

The IRF510 is more of a switch and not designed for linear RF amplification but it is cheap and works great for QRP.  They have different bias requirements from one unit to the next.  That is why you carefully set the bias level with a trim pot.  The large heat sink was part of an old high power LED driver that died.  I used T37-6 toroid cores for the low pass filter on the right. The 2nd relay was needed to prevent the output of the IRF510 feeding back into the original PTT switch and back into a nasty loop.

I am not sure if this rig will ever get a case or future modifications but I do know that I would like to see if I can make more contacts with it.

I would like to end this article with a quote I very much like from a video with Rev. George Dobbs, G3RJV

“Radio construction is rather like a pilgrimage where the journey is often more important than the destination”.

73,

Mike,  AB1YK