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Hello, again. This is Trey. 

Welcome to part 4 in my Cheap Yellow Display (CYD) Project series. If you have hung in there with me so far on this journey, thank you. If you have missed earlier episodes, you can find them on my

HPR profile page



https://www.hackerpublicradio.org/correspondents/0394.html

  

If you have questions, comments, concerns, or other feedback, please leave an episode comment, or drop me an email (Using the address in my profile). Even better, you could record and upload your own show which shares your viewpoint or expertise. 

To review, I finally have an actual project to build using the CYD. It is a portable, programmable morse code "Keyer memory" which can be connected to any of my HF transceiver radios by simply plugging it in to the code key input port. Then I could transmit stored messages by simply touching their specific icon on the touch screen. 

So, now I purchased a pair of CYDs. Each arrived in an anti-static zipper bag with a USB C cable, a 6 inch long 4 pin PB1.25mm to Dupont 2.54mm cable harness, a plastic case holding the CYD itself and a small plastic stylus. There are pictures in the show notes. 

Depending on how many IO connections I may need, and how I plan to power this, I am probably going to need more 4 pin PB1.25mm wired connectors. 

You can see a description of the various features and connectors on

RandomNerdTutorials

writeup about this board (

https://randomnerdtutorials.com/cheap-yellow-display-esp32-2432s028r/

). The only difference I can see between this description and what I received is that mine have both a MicroUSB and USB C port.   

 

Of course, first thing, I had to plug it in and see what happens. 

It appears to be running some kind of simulation of a web site. The backlit display looks alright. It is not super high resolution, but for the price, it will suite my needs. The touch screen is responsive, but it is pressure sensitive and works best using the provided stylus or a fingernail and not your finger tip. 

So, I have the CYD. What other hardware do I need? 

I need to address how one of these will actually connect to my radios. Modern amateur radio transceivers which support continuous wave (CW) transmission (Which is another name for Morse code) generally can use one of two different pieces of hardware for input. 

The first is what we call a straight key. Below is a photo of the one I own. 

This is a classic, old fashioned telegraph style code key. It is designed to quickly and easily be pressed down to close a circuit and when released the circuit is opened, effectively making it a normally open push button switch. To send a dot, the operator holds down the key for a short period of time, then releases it. To send a dash, the operator holds down the key for a longer period of time, before releasing it. (We will discuss actual timing specifications for morse code in a future podcast) Connectivity for the switch has been standardized to use a 3.5 mm mono male phone connector which has only sleeve and tip connections.   

The second option is a paddle style electronic keyer. There are many styles of these, and I am including a picture of the one I use, which once belonged to a close friend of mine who is now silent key. 

In general, the paddle is two separate normally open switches. In the most common configuration, if an operator presses and releases the paddle on the right, a dash is sent. If the paddle on the right is held, a continuous series of dashes will be sent until that paddle is released. 

The left paddle works similarly. If it is pressed and released, a single dot is sent. If it is pressed and held, a series of dots is sent until it is released. The function of these paddles can be swapped from left to right using the radio configuration. There is additional functionality which can be configured in some radios for when both paddles are pressed simultaneously, but I am not going to describe those here.   

The paddle generally uses a 3.5mm stereo male phone connector with the sleeve being common. The tip of the phone connector is wired to the left paddle and ring of the connector is wired to the right paddle. Most modern radios have a built in keyer which can be configured for a paddle and will automatically transmit the dots or dashes at whichever speed is configured based on the paddle pressed. 

You can see this phone connector illustrated on

Wikipedia's phone connector page.

. 

https://en.m.wikipedia.org/wiki/Phone_connector_(audio

)  

You can learn more about all the various devices which can be used for sending morse and how they function at

Morse Code World

.

https://morsecode.world/keys.html

  

Ideally, controlling all the morse code timing within the CYD would be best. That way, it could be connected as a straight key and any keyer settings already configured within the radio shouldn't matter. However, If I wish to also be able to manually send morse code myself using my paddles, without disconnecting the CYD and reconfiguring the radio, that could be problematic. I may need to factor in the possibility of connecting my paddle to the CYD and then building in code to respond to inputs from the paddles.  

As I mentioned in a previous episode, I have an Arduino Nano on my desk as a practice oscillator for my paddles. I may be able to reuse some of that code on the CYD. 

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