Bluetooth keyboard as serial monitor input.

My RTTY tranceiver is all working, until I go into transmit, when the PS/2 keyboard passes RF into the screened enclosure and fills the transmit buffer with rubbish! I have done everything I can think of to filter it, but the best I have achieved is for the keyboard to stop sending anything which I suppose is better than sending rubbish.

My idea is to forget the PS/2 keyboard and go Bluetooth, straight into the serial pins on the Nano. I bought an HC-06 but gather that it is slave only and I actually need the HC-05 which is now on order.

My research doesn't throw up any articles about connecting a Bluetooth keyboard for this sort of use and I wonder if someone could point me at some resources please?

My RTTY tranceiver is all working, until I go into transmit, when the PS/2 keyboard passes RF into the screened enclosure and fills the transmit buffer with rubbish! I have done everything I can think of to filter it, but the best I have achieved is for the keyboard to stop sending anything which I suppose is better than sending rubbish.

What? This doesn't make sense to me. Don't use abbreviations without declaring them (p.e. RTTY, RF)! How is the PS/2 (I expect this to be a PC keyboard connected to the controlling PC) sending rubbish? Is it damaged? Where do you filter it? On the PC?

My research doesn't throw up any articles about connecting a Bluetooth keyboard for this sort of use and I wonder if someone could point me at some resources please?

A Bluetooth keyboard won't work as it implements the HID profile and not the serial profile.

AJLElectronics:
My RTTY tranceiver is all working, until I go into transmit, when the PS/2 keyboard passes RF into the screened enclosure and fills the transmit buffer with rubbish! I have done everything I can think of to filter it, but the best I have achieved is for the keyboard to stop sending anything which I suppose is better than sending rubbish.

My idea is to forget the PS/2 keyboard and go Bluetooth, straight into the serial pins on the Nano. I bought an HC-06 but gather that it is slave only and I actually need the HC-05 which is now on order.

My research doesn't throw up any articles about connecting a Bluetooth keyboard for this sort of use and I wonder if someone could point me at some resources please?

I built an Arduino CW keyboard using a PS/2 keyboard and had the same problem.

You have diagnosed the problem, but have the wrong culprit cornered! The keyboard itself is the problem. It has it's own processor and sends both the key data and an accompanying clocking signal to your Arduino. The data is corrupted in the keyboard before it ever gets to the Arduino.

I took the keyboard apart and could find no way to shield anything from RF. Obviously the use of a PS/2 keyboard was a very poor choice for use around RF!

I still have the project, but can't use it!

73, Paul, KD7HB

I am sure that you don't actually intend to be so abrasive, so I will ignore it for now. Although you can't necessarily be expected to know what RTTY is, the abbreviation RF is perfectly well known by anyone involved in electronics as being Radio Frequency.

The device is a modem for a method of communication that you might know as Telex or the trade name Teletype. When sent over radio rather than a wired circuit, it is known as RTTY.

I didn't mention a PC because there isn't one. The PS/2 keyboard is straight into the Arduino in a fully screened enclosure and works fine until I try to transmit. My testing has shown that the RF is getting in via the keyboard, hence my idea to have a cordless keyboard to reduce the pickup.

Your last sentence was however useful, if disappointing so I will have to look into other ways of improving the screening of the keyboard.

Thanks for your input.

Thanks Paul, I have managed to quieten it down a little, I'm sure that you are right. The first one I built was plastic cased and is impossible to use on the lower bands where all the activity tends to be! Interesting point about it actually sending corrupt data, that seems to make perfect sense.

This later version is built into a die cast enclosure and is far more resistant, maybe I can improve things enough to tip it over the edge enough to be useful. It is a real shame that I can't use the Bluetooth keyboard, it would have been perfect ergonomically too.

73 de G6FGO

My keyboard came from a local thrift store, I think. Wasn't aware of a die-cast keyboard.

My station digital computer is an old HP laptop. When running FT8 on 40 meters, the cursor would lockup when transmitting, but many times would work after switching to receive. Sometimes it would never work.

After many frustrating tries with ferrite cores, I grounded the thing to the station ground, using a screw into the hole where a safety lock would be fastened. That did the trick for all bands. A metal case keyboard and direct ground might work for you. I will look for a die-cast keyboard. They must be quite rate.

73, PAul, KD7HB

I don't think so, found this one pretty readily
www.solidsignal.com/pview.asp?p=ST-TCAWKM&utm_source=google&utm_medium=cse&utm_term=st-tcawkm&gclid=EAIaIQobChMIhdyvzZ-26AIV54FaBR3eIwgnEAYYBiABEgKiHPD_BwE

(delete the extra characters the forum added to the front)

I have discombobulated (just remembered that word!) you Paul.

My project is built in a die cast case, the keyboard is merely a mass market plastic jobby. I have used chokes, ferrite rings and capacitors to quieten it down with very little effect. That having been said, I did a test a little earlier on 40 metres and it worked OK, so it must be the variation in the RF field. I do have quite a lot of RF in the shack anyway, so once I get to the bottom of that, things might improve. I will post some photos etc when back on the PC, doing anything with the iPad on this forum is too much of an ordeal. :wink:

Here are a few posted to different thread... https://forum.arduino.cc/index.php?topic=668475.45

I have audio tweaks to do now, from my testing so will come back to the keyboard issue. I am sure that there is a way I can achieve cordless operation, more research and lateral thinking required methinks!

Thanks again.

Here's a thought... Infra red serial link. First hit on a forum search here:

AJLElectronics:
Here's a thought... Infra red serial link. First hit on a forum search here:

https://forum.arduino.cc/index.php?topic=10555.0

Ok, but remember the PS/2 keyboard requires a 2-way communication. The PC can write back any time to turn on leds, etc. May not be a problem for you.

Paul

Doesn't matter, it only needs to tx the ASCII, the LEDS and extended functions are irrelevant, although it might be handy to get the function keys triggering prewritten CQ and RYRY memories though. I could do those either from a hard coding or stored on an SD card. That's a design for later down the line though.

I did have a look for metal keyboards after being prompted by Mr Crossroads above. They do exist at a price, although some of them are metal fronted with a bare PCB on the back, sold as "vandal proof".

I'm starting to think that the IR option is the one to pursue next.

AJLElectronics:
Doesn't matter, it only needs to tx the ASCII, the LEDS and extended functions are irrelevant, although it might be handy to get the function keys triggering prewritten CQ and RYRY memories though. I could do those either from a hard coding or stored on an SD card. That's a design for later down the line though.

I did have a look for metal keyboards after being prompted by Mr Crossroads above. They do exist at a price, although some of them are metal fronted with a bare PCB on the back, sold as "vandal proof".

I'm starting to think that the IR option is the one to pursue next.

Some more information for you to ponder. The keyboards do not send ASCII. They send a key-code when the key is pressed and a second keycode indicating the key is released. If a key is held, the second code is not sent until the key is actually released, so the computer knows the key is being held down and can take appropriate action.

This is how keyboards with other than English letters on the keys can function.

Paul

Thanks, I think that I could still use the Bluetooth modules if I have a Nano driving the keyboard end. That way it is just a serial link.

I have been doing a little more on the project and had a contact with a German station this morning. Keeping the power down kept it stable and even with 5W I got a 599.

Some pictures are ready, so I will see if I can upload them now...

And some more...

Some more...

The linear regulators live in the bottom of the case, well heatsinked and properly bypassed with SMD capacitors.

And in use...

pylon:
Don't use abbreviations without declaring them (p.e. RTTY, RF)! How is the PS/2 (I expect this to be a PC keyboard connected to the controlling PC) sending rubbish? Is it damaged? Where do you filter it? On the PC?
A Bluetooth keyboard won't work as it implements the HID profile and not the serial profile.

The problem is we all use abreviations, assuming they are obvious and everyone else must understand them.