Tag Archives: Arduino-Raspberry Pi

DX, Featured, General, Homebrewing, Newsletter, On The Air

DX Alarm Clock Part 2 – Hardware

I recently wrote a blog article about the DX Alarm Clock software – here is Part 2 of the Series on the how I built the hardware for the DX Alarm Clock.

DX Alarm Clock Hardware Components

The DX Alarm Clock is based on a Raspberry Pi 3 computer and an Adafruit Pi-TFT Touch Screen Display.  The list of components, along with links is below.  Since I built the Raspberry Pi almost a year ago and technology is always advancing, some of the parts are no longer available or have better replacements available.  I’ll provide information on what I used and a recommended replacement.  Approximate prices are included.

Raspberry Pi 3
Raspberry Pi 3

Motherboard: Raspberry Pi 3 ($35) – includes a 1.2 GHz 64-bit quad-core ARM CPU, Build in WiFi, Ethernet, 4 USB Ports, an HDMI port and audio port (3.5″) and Bluetooth.

Also, you will need a power adapter  ($10) and Class 10 Micro SD card ($15) for the Raspberry Pi.  Ours is a SanDisk Ultra 64GB Micro SD Card.

Pi-TFT Touch Screen Display
Pi-TFT Touch Screen Display

Display: Adafruit Pi-TFT 2.8″ Display with Capacitive Touch Screen ($45).  A slightly larger, 3.5″ display is now available.

PiBow Case
PiBow Case

Case: Pimoroni PiBow Case for Raspberry Pi and Pi-TFT Display($20)

Kinivo Speaker
Kinivo Speaker

Portable Speaker:  Any small portable/rechargeable speaker will do.  Mine is a Kinivo, but it is no longer available.  Any small speaker will do as long as it is Bluetooth or has a 3.5″ stereo connector.

Completed DX Alarm Clock Hardware
Completed DX Alarm Clock Hardware

The picture above shows the completed DX Alarm Clock Hardware running portable using a USB battery pack.

Raspberry Pi Development Environment

Raspberry Pi Development Environment
Raspberry Pi Development Environment

After constructing the Raspberry Pi, case and TFT Display, the next step was to connect it to a monitor via the HDMI port, a mouse via one of the USB ports and to a Bluetooth keyboard.   Then I loaded the Raspbian Operating System onto the Raspberry Pi via the micro SD card.  I first copied the OS to the Micro SD card using a PC or Mac and then inserted the card into the Raspberry Pi and booted from it.  You can find a good tutorial on how to do this at https://www.raspberrypi.org/learning/software-guide/quickstart/

Once Raspbian is installed, you will have a windows like GUI (Graphical User Interface) environment with a web browser, and a number of additional applications included.

This gave me a development environment that I could use to build and test the DX Alarm Clock software.  I used the Python language to develop the software.  I used the Python IDLE development environment, which is included in the Raspbian OS.

Interested in Raspberry Pi Amateur Radio Projects?  See the article on a Raspberry Pi Satellite Rotator Interface.

Featured, General, Homebrewing, Newsletter, On The Air, Station Equipment

Add CTCSS PL Tones to Your Old VHF Rig

Last week I gladly accepted a free Azden 2m FM transceiver model number PCS-4000 that was offered to me.  You have to love the old free stuff!  The only capability this 25W rig was missing is the ability to transmit CTCSS PL tones or sub audible tones to activate a repeater.

I found the manual and schematics online and found that this rig was built to accept a tone generator as an add-on. See below.

PL Tone Mod Circuit

Below is a photo showing the jumper locations for the tone input.  I soldered some leads with a home brew disconnect to easily remove the cover in the future.PL Tone Mods

Below is a photo showing an added 1/8″ mono jack for the input tone.

PL Tone Mods

For an input tone, I used an Android cell phone with a frequency generator App to generate the PL tone.

PL Tone Generator

I can experiment with other ways to generate the tone such as an Arduino with RC filters etc.  I can also try to insert a 700 Hz tone with my Arduino keyer for MCW.

Below is a photo of the rig set up for a local repeater.

Completed Mod to add PL Tones

So now to quote Pete Juliano “Bob’s your uncle”!!!

73,

Mike, AB1YK

CW and QRP, Featured, General, Homebrewing, Newsletter, On The Air, Station Equipment

My SSB BitX-40 build from VU2ESE

Below is a photo of my BitX-40 kit from Ashhar Farhan VU2ESE in India with my very own custom designed case.  The kits are available from http://www.hfsigs.com/

The top cover shown is powder coated steel mesh.

BitX-40 Enclosure

The sheet metal housing was designed in a solid modeling software package called Onshape. This web based software is free to use if your designs are to be available to anyone who signs into an account.  This design is “in the cloud” and considered “open hardware”, available to anyone who would like to use it.  Below is a screen capture of my Linux desktop running Onshape within a web browser.

BitX-40 Enclosure CAD Design

With access to a CNC punch press and a 90-ton brake press, a coworker of mine helped out with a bit of “government work”!

I left out some of the detail in the housing to let others enjoy the use of a drill and allow for some creativity with a customized placement of components.

BitX-40 Enclosure with Board

Some of the wires are not needed but may be useful in future “hacks”. The image below shows some of the wires removed from the “Molex” connector.  A small sharp object can be used to push in on the barb to remove the contact for a future project.

BitX-40 Cables and Connectors

See http://bitxhacks.blogspot.com/

I used my sketch to drive the LCD screen and the SI5351 chip using the Adafruit library.  The checkered block moves left and right between the arrows to indicate when I am at or near the end of travel with the tuning potentiometer.

BitX-40 Frequency Stationary
Stationary

When I move the block all the way to the right with the potentiometer it turns into an arrow and automatically increases the frequency. To make it stop just turn the potentiometer to the left.

BitX-40 Frequency rising
Frequency rising

I like the ability to scan the band without having to turn a knob!

Below is an image showing 12v and 24v voltage regulators and electrical tape on the housing tabs.  12v is for the majority of the wiring and I used 24v for the IRF510 PA.  The black tape looks nice behind the black mesh cover.  while testing I measured about 4W RF output with 12v feeding the PA and 16W RF at 24v.

BitX-40 Enclosure

The bottom has extruded “feet” along with stick on feet to keep the rig from sliding.

BitX-40 Enclosure

I used an SO-239 connector for the antenna.  I saved the BNC connector from the kit for test gear.  The red terminal post is connected to 32v from a repurposed HP printer power supply.  The barrel jack is connected to 16v from the same supply.

For more information on the case, you may contact me through my QRZ page.

73,

Mike (AB1YK)

Radio Amateurs Developing Skills Worldwide