# Custom Keyer Project: Needs helps, preferably someone with circuit design experience/knowledge

#### Sanz of Time

Joined Mar 19, 2015
11
So I'm building a couple of custom keyers (http://i.imgur.com/eHos1yi.jpg), but I've run into a problem with the circuitry. I can explain how it's supposed to work as a keyer if need be.

My idea was to use one of the smaller arduinos (nano or micro, I forget which) in one of the keyers while the other simply had a multi-in, single-out ic that would go down the line of keys, thanks to a timer, and send them through RF to the keyer with the microcontroller.

Essentially, one controller sends a hex value to the controller constantly and if there's a 1, it's a keystroke. But what specific circuitry do I need? How do I get the timer to make the MISO to cycle through the keys, what capacitor do I need so the timing is right, what program do I use to simulate this, where do I ground it all?! It's madness.

So yeah, besides hooking up the keys, I'd like to integrate an optic mouse so I don't have to take my hand off of the keyer to move the mouse, but that's just an extra feature. if I can even fit it onto the arduino board.

#### Sanz of Time

Joined Mar 19, 2015
11
I should have changed the title, I just copied it over from another forum that wasn't focused entirely on people with circuit knowledge. Welp, so much for that.

#### blocco a spirale

Joined Jun 18, 2008
1,546
What have you got so far? Schematic? Block diagram? Specification?
I don't know about anyone else but I have no idea what you're talking about.

#### Sanz of Time

Joined Mar 19, 2015
11
Sorry about that, I'll try to be clearer. Man, I didn't even explain what a keyer was. Essentially a keyer is just a keyboard but not in the traditional set-up (DataHand, for example). It's meant to take keystrokes, like a regular keyboard, and send them to the computer, like a regular keyboard. The only difference is that it looks different.

There's going to be a left keyer and a right keyer with 4 regular keys, and 2 shift keys (on top) each. The 4 regular keys will enter letters and symbols, and the 2 shift keys will change what the regular keys input (like when you click 'shift' on your computer, it changes all the letters to be capital letters and all the numbers to be symbols). Since I'm not going to connect the two keyers together, I'm sending the information wirelessly through RF. Instead of buying two microcontrollers, I thought that I could get away with using only one microcontroller. The arduino board would be in the right keyer since, if I was going to implement an optic mouse that's where it would go. So now I had a problem: how do I send information from the left keyer to the right keyer? My solution was to use a Multi-Input, Single-Output (MISO) ic to shift through keys and shifts in a sequence (keys 1-4 then shifts 1-2). It would send something similar to this, where x means "doesn't matter" [xx01 0100]. This means that the 1st shift button is pressed, along with the third key (which could mean I meant to type "g"). I called it a hex value, but in reality, the RF is just sending 1's and 0's and the arduino board in the right keyer is interpreting them is sets of 6. So then the right keyer receives that bundle of information, stitches it together with its own keystrokes to understand what letter/number/symbol the user wanted (e.g. Right: 1000 10, Left: 01 0000, Together: 1000 0001 0100 = "g"), and then tells the computer what keystroke it was. Please tell me if I failed to communicate properly, that was a lot of text.

The problem I'm having now is that I don't know how to design a proper circuit for this. I'm drawing up a quick circuit diagram for the general idea of the two keyers.

#### Sanz of Time

Joined Mar 19, 2015
11

#### blocco a spirale

Joined Jun 18, 2008
1,546
If this is all you've got, I think you will struggle as it looks like you need someone to design it for you.

Forums are Ok if you already have something but require a little help with specific questions but if you present an ambitious project idea and say "I don't know where to start" then you've got a problem as electronic design is a very time consuming process.

#### Sanz of Time

Joined Mar 19, 2015
11
I just need help with sending information from the left keyer to the right one, the MISO/RF portion. I can probably figure everything else out from there since there are other resources for using arduinos as a keyboard.

#### SgtWookie

Joined Jul 17, 2007
22,220
I'm curious why you don't want to use another Nano or Micro or something similar, because you'd be able to effectively change the circuit by changing the programming; whereas with logic ICs (like 4000 series CMOS or 74xx series) you would have to swap out ICs and re-wire to change the circuit.

You can buy Arduino Nanos on auction sites for just a couple of dollars. Add an RF module for a buck or two to both Arduinos, and you're done. You can do all of the switch debouncing in programming.

#### Sanz of Time

Joined Mar 19, 2015
11
I'm curious why you don't want to use another Nano or Micro or something similar, because you'd be able to effectively change the circuit by changing the programming; whereas with logic ICs (like 4000 series CMOS or 74xx series) you would have to swap out ICs and re-wire to change the circuit.

You can buy Arduino Nanos on auction sites for just a couple of dollars. Add an RF module for a buck or two to both Arduinos, and you're done. You can do all of the switch debouncing in programming.
I was doing it because it's cheaper (didn't know about this site until a couple days ago), and cause I thought it would make for a good challenge. I feel like I've relatively solved the issue, but I still don't know the proper way to design the circuitry (could I just hook buttons and the RF to a second board and that's it? Or do I need a resister between the buttons and the board? Do I need a small capacitor between to account for the bounce that occurs when a button is pressed?).

But I guess I'm just gonna take the easy solution then.

#### blocco a spirale

Joined Jun 18, 2008
1,546
So, you say you've "relatively solved the issue"; have you selected the hardware but don't know how to connect it? Have you an example of the "MISO" that you're considering using?

Whatever you use; key debouncing will be necessary and possibly pull-up resistors on the inputs to... whatever....?

A micro-controller is probably the best way forward but it's very difficult to know, from what you've written, where you are with the whole thing.

#### Sanz of Time

Joined Mar 19, 2015
11
Just ignore I've said anything. I've made a thorough idiot of myself.

#### SgtWookie

Joined Jul 17, 2007
22,220
I don't think that. Neither should anyone else. It's an interesting application that could be solved in a number of ways, each with strengths and weaknesses. One of your requirements will be power; did you have a source in mind? Having them wired would enable using "wall wart" type plug supplies and possibly eliminate the need for the RF modules, but adding the problem of metal fatigue.

One added benefit of using microcontrollers in both units might be that you could make them both identical, and have the software reflect which unit will be master and which slave.

#### Sanz of Time

Joined Mar 19, 2015
11
I came in and said "I don't know anything, please do this for me", confused everyone by being incomprehensible (if all the "what are you talking about/what do you want" are any indication), and then decided to stick with my original "design" I knew absolutely nothing about even though a much easier and simpler idea was presented. I think calling myself dumb is not entirely wrong.

As for power, I figured I could strap enough batteries together to get enough power, I'm not sure what parts I'll need yet, so I don't know how much power I'll need. I'm perfectly fine with using two microcontrollers (now), but I'm rather adamant on then being wireless.

#### Papabravo

Joined Feb 24, 2006
14,871
We are not here to cheer for the success or failure of anybody's ideas. Where we can be useful is to focus or refocus your efforts along lines with a high probability of success. If we cannot get you to describe your requirements in comprehensible terms then we have one hand tied behind our backs. If what you want to do is not obvious or impractical for one reason or another that ties our other hand, and you need to be aware of that as well. We have no reason to want to thwart you efforts in accomplishing your goals.

Although we are often accused of doing that when people don't get the answers they want or expect. If we don't satisfy your needs you're free to vote with your feet or fingers and seek advice elsewhere. We don't have anything approaching a monopoly in the advice business.

#### Sanz of Time

Joined Mar 19, 2015
11
We are not here to cheer for the success or failure of anybody's ideas. Where we can be useful is to focus or refocus your efforts along lines with a high probability of success. If we cannot get you to describe your requirements in comprehensible terms then we have one hand tied behind our backs. If what you want to do is not obvious or impractical for one reason or another that ties our other hand, and you need to be aware of that as well. We have no reason to want to thwart you efforts in accomplishing your goals.

Although we are often accused of doing that when people don't get the answers they want or expect. If we don't satisfy your needs you're free to vote with your feet or fingers and seek advice elsewhere. We don't have anything approaching a monopoly in the advice business.
Thank you very much, all of you, honestly. I'd like to apologize to you all. I don't mean to seem unappreciative. I was just frustrated with how poorly I handled things, from the initial idea, to how I described it, to my responses when help was presented.

I know what it's like to have some new kid come to a forum who asks something and has a little tantrum when they don't get the answer they want, and I'm embarrassed to say that today, it's me.

Again, I'd like to apologize for my behavior and hope to gain a lot of knowledge from this forum. Thank you.

#### SgtWookie

Joined Jul 17, 2007
22,220
I've seen much worse. Don't worry about it; nobody starts off in any given subject knowing everything about it.

When Arduinos were brand new, they weren't cheap. Nowadays, if you do just a bit of looking, you can buy 3, 4 or more Micro or Nanos for $10 on auction sites. Same with the RF modules. Sometimes, it's fun just to "roll your own" designs. However, you will likely have a much greater chance of success if you use COTS (Commercial Off-The-Shelf) modules and plug them together in a logical fashion, and program them to accomplish the objective. It's a LOT easier to change software than hardware. If you're planning on making more than a few of these, then Arduinos might not be the best platform. However, it's great for prototyping. Thread Starter #### Sanz of Time Joined Mar 19, 2015 11 I've seen much worse. Don't worry about it; nobody starts off in any given subject knowing everything about it. When Arduinos were brand new, they weren't cheap. Nowadays, if you do just a bit of looking, you can buy 3, 4 or more Micro or Nanos for$10 on auction sites. Same with the RF modules.

Sometimes, it's fun just to "roll your own" designs. However, you will likely have a much greater chance of success if you use COTS (Commercial Off-The-Shelf) modules and plug them together in a logical fashion, and program them to accomplish the objective. It's a LOT easier to change software than hardware.

If you're planning on making more than a few of these, then Arduinos might not be the best platform. However, it's great for prototyping.
Good point. I'm only going to make one set, maybe a second for a friend, so it's not bad, especially since I can use this auction area. I doubt it's likely, but what would happen if someone sold me something broken or not working?

#### Sanz of Time

Joined Mar 19, 2015
11
You really want something like this..
Bluetooth right in the keyer and forget about something physically attached to the computer..

Bluefruit EZ-Key (google it and away you go)..
This very much is something I'm looking for. I like how they explain all of their pinouts and tell you how to perform common, basic, ideas with those pins (like adding an external button to the Bluetooth pairing button pinout. Thanks guys

#### mcgyvr

Joined Oct 15, 2009
5,394
yeah adafruit/Limor does a great job with tutorials/libraries,etc.. for products she sells..
They might not be the cheapest source but its worth the extra few pennies to show support for that kind of company..