deskthority

So I was showing Chyros' YouTube video reviews of the Beamspring keyboards to a work colleague. She was horrified about the sound they make when each solenoid is on. I told her, teasingly, that I was going to get a Beamspring with TWO solenoids, one on each side of the keyboard, to enjoy double the noise (in Stereo!).

Obviously, I said that in jest... but now I am wondering whether this may be technically feasible. Could it? The easier route would be to simply duplicate the signal sent from the controller, so both solenoids would act together, but the more interesting idea would be for them to alternate each keystroke, something that would allow fast typists to get the proper thump on each keystroke.

Now I wish I did have a Beamspring.

xwhatsit designed replacement controllers for capacitive boards such as a few IBM beam springs - with an optional solenoid driver board.
As I understand it, there is only a trigger signal from the controller to the solenoid driver and to get two solenoids you would need a second driver board and a second line from the controller to that.

depletedvespene wrote: ...with TWO solenoids, one on each side of the keyboard, to enjoy double the noise (in Stereo!).

Totally over the top, Beamspring solenoids are LOUD enough trust me and "stereo" does not work that way IMO.

seebart wrote: Totally over the top

That's the point!

seebart wrote: and "stereo" does not work that way IMO.

It is if each solenoid is on either side of the keyboard.

A way to fake it would be to get one of those programs that makes a sound every time you press a key -- and configure it to play the sound of the solenoid. Those shouldn't have any problem with repetition time.
Then carefully place the speakers inside or under the keyboard with a ramped-up volume.

seebart is right stereo doesn't work that way. You are just going to get a louder mono sound if you manage to get the voltage and such right. Now you could get creative with the solenoid housing and make it louder / more "room filling".

codemonkeymike wrote: seebart is right stereo doesn't work that way. You are just going to get a louder mono sound if you manage to get the voltage and such right. Now you could get creative with the solenoid housing and make it louder / more "room filling".

Exactly. Real stereo is a specific audio-technical process, not just two sources on either side and since it's a flat clicker-like sound it couldn't be stereo anyway. Of course it will be louder, the key is that both would really have to be in sync or it might suck if the feedback isn't 100% lined-up. I'd love to hear it though.

https://en.wikipedia.org/wiki/Stereophonic_sound

You could totally just wire two in parallel. I don't think it will take fancy electrical magicneering.

PS: Dual mono is what you are looking for, not stereo. Not to be confused with dual mono in, which means 2 independent channels, dual mono usually means a single mono signal with 2 outputs.

All of a sudden I have a desire to see someone hook one of these solenoids up to an arduino and try to coax music out of it...

You're (y'all're?) right. To get a "true" stereo, the controller should fire the "left" solenoid for the QWERT-side keys, and the "right" solenoid for the YUIOP-side ones. Damn, I wish I were any good with electronics.

The solenoid itself does not make much noise. When mounted/attached to the case, the case acts somewhat like a speaker and amplifies the sound. Therefore the result of adding a second solenoid may not not have the effect you intended.

As far as wiring two in parallel, if you reuse the driver for a single solenoid, you will want to consider the supply current needs, the size of the output capacitor, and the flyback diode used to be sure 2 solenoids can be handled.

Here is an ever nuttier ideea: instead of the second solenoid, install a mechanichal typewritter bell and write a script that identifies the row end in Word

derzemel wrote: Here is an ever nuttier ideea: instead of the second solenoid, install a mechanichal typewritter bell and write a script that identifies the row end in Word

Great idea! Of course there could be other script for the typewritter bell...

I was going to try the bell idea a while, but kind of lost how the bell assembly went together on the typewriter I disassebled. Basically you would just put that on instead of a solenoid as the bell itself is solenoid driven, not sure how similar the voltages are, but a short burst of 9V shouldn't roast anything I wouldn't think Maybe I'll have to see if I can out today.

The problem is the power draw. USB port that it uses can put out about 500mA. Controller itself needs a little and then the solenoid board needs about another 200mA IIRC. Solenoids are power hogs. Two solenoids on the same USB bridge is cutting it really fine.

Now feed it an external +5VDC supply, say from a wall wart, and you can stick in as many as you want/as many as your external PSU allows. Standard 1.5A one would get you about 6.

rich1051414 wrote: You could totally just wire two in parallel. I don't think it will take fancy electrical magicneering.

PS: Dual mono is what you are looking for, not stereo. Not to be confused with dual mono in, which means 2 independent channels, dual mono usually means a single mono signal with 2 outputs.

All of a sudden I have a desire to see someone hook one of these solenoids up to an arduino and try to coax music out of it...

Been done. https://www.youtube.com/watch?v=sR3xmof8rZY It's fun because it also has a little lesson on shift registers which is how keyboard matrices are traditionally scanned.

Also, the solenoid boards can't handle two. They can barely handle one without bogging down. You need a solenoid board for each one. The triggering signal from the main controller can go to as many as needed though. It's just gate voltage so current needed is teeny tiny.