Links - Buttons & Switches

[pappajackson]

I've been doing lots of googling in search of the perfect illuminated button and rotary knob. I've found a few sites so I thought I share them. I'm new to midibox and it took me a while before I actually knew the right type of button or rotary to look for. For the fellow noobs, you need to 'push-to-make' buttons.

http://www.rjselectronics.com/ - a huge collection of buttons and switches, plus a nice 20x2 LCD

http://www.itwasia.com.tw/e-switch.htm#3 - more cool buttons, check out the big silver anti-vandal button!

http://www.aliceshop.com/acatalog/AliceShop_Series_A_Spares_43.html - a few fader and rotary knobs in lots of different colours.

http://www.apem.com/hardware.html - loads of buttons/switches and a few cool retro knobs

http://www.okw.co.uk/products/okw/tuning-knobs.htm - loads of knobs

http://www.maplin.co.uk/Search.aspx?criteria=knob&doy=1m4&source=15 - an obvious one here, but still thought it might be usefull. The calibrated and pointer pair's (about two thirds down the page)are nice.

That's all for now, hope this is handy to someone. I'll post more if I find them.

[stryd_one]

The "push-to-make" switches are also known as momentary switches, or more correctly in our case, SPST Momentary, which stands for Single Pole Single Throw. Momentary switches are those which switch on when you push them, but switch back off again when you release them - they're only 'ON' for the "moment" where you are pushing them in.

Hope that helps. It's actually something which doesn't appear to be mentioned, I should add to the wiki. Thanks for pointing it out, and for the links too :)

Oh and those anti-vandalism switches are pretty looking, but they're not designed to be easy to push (that ease of use is sacrificed in order to achieve a more solid device), and they're greatly overrated (120V,10A)... might not be the best thing for a MIDIBox...

[pappajackson]

Yeha, I thought the anti vandal one might be good for a power switch. I'll probably just use a basic rocker.

[stryd_one]

You don't want a momentary for a power switch, or it will only be on while you hold it in, so your midibox would turn off unless you kept one finger on it all the time.

[pappajackson]

:Slaps forehead

Oh yeah....

[Tibia]

A normally open push button could be used as a power switch... but you will also need the push button wired to the coil of a control relay.

Then wire one of the control relay's normally open contacts in parallel to the start push button.

If, for some strange reason, you would want to turn off the unit...  a normally closed push button would need to be wired in series with the control relay's coil.

The rocker switch is much simpler ;)

Bob

[drin]

The rocker switch is much simpler ;)

And it looks pretty too. :)

-drin

[MEEF]

thanks for the links!

would using momentary buttons for stuff like solo only make the solo go on when when the button is pushed down?

[stryd_one]

That's right.

[MEEF]

ok right, so a latching switch could be better so stuff like that & other mixer buttons...

[dengel]

That's right.

Stryd, this depends on the application. Ableton's solo/cue behavior by default toggles back and forth between on/off in the software, even with a momentary switch. I've tested this with both MIDI and Kb input.

I think that Meef should look into whether an event must be sent CONTINUOUSLY or Mometarily to determine the switch type. In things like Power, obviously you want the switch to always stay in the closed position when enabled, in which case a mechanical toggle is a good choice. But in the case of software functions, many are activated by a note event and kept going, and deactivated the next time the same note is pressed.

[stryd_one]

Stryd, this depends on the application.

Well in this case it depends on whether you're talking about a control surface for an application or a real analog audio circuit... I was taking about the latter, because up until your post, nobody mentioned software at all, so the application was a circuit.

If you're talking about a control surface for software then the required switch still doesn't have much to do with how ableton responds, as the state of the switch is converted to a MIDI message depending on how the MIDIBox is configured, and that MIDI message controls ableton... So the correct switch is dictated by the MB application, not ableton.

Ableton, being software, won't try to use an absolute value for the solos/mutes/etc, because in that scenario, if somehow a MIDI message was dropped, then the function of the virtual switch would be reversed. So instead, it is relative to it's last value (not absolute) and just swaps the value whenever it receives the corresponding MIDI message.

This is typical of digital circuitry: Why would you bother with any other type of switch than momentary? You can have a momentary switch swap the value of a variable between 1 and 0, so a momentary can be easily used to emulate the nature of a latching switch.

I hope this isn't too hard to understand. It's much easier to explain with some breadboard :)

[dengel]

Well in this case it depends on whether you're talking about a control surface for an application or a real analog audio circuit... I was taking about the latter, because up until your post, nobody mentioned software at all, so the application was a circuit.

Haha! Sorry; forgot I had seen other post where he mentioned Ableton just before I saw this post. Great explanation of why Momentaries are almost universally used for MB stuff.

[stryd_one]

Hehehe you know, I almost didn't post that, I was thinking to myself, "dengel already knows this"  ;D

Ahh well as you say, maybe it will serve as a tutorial :)

[marcvangend]

You don't want a momentary for a power switch, or it will only be on while you hold it in, so your midibox would turn off unless you kept one finger on it all the time.

That's probably true in 99.99% of the cases. But you got me thinking...

(as you know, stryd_one) I am planning a midi footswitch to select channels on my bass amplifier. This footswitch would only have to be on at the moment I'm switching channels, which is maybe 10-20 times during a gig. Mechanically, it cannot be difficult to link the power supply to the momentary switch, meaning: when you push the button, power comes on and the midi signal is transmitted. When you release the button, the power is turned off again. This would save power, probably making it possible to power my switch with a 9V battery, which is sometimes a convenient option on stage.

Now I have to remind you that I'm only a newbie. I don't know if there's a time lag (a startup time) between power-on and signal-transmit. Maybe this whole idea is impossible for reasons I can't even imagine. However, I wanted to share it with you... I'm curious what y'all think!

[Rowan]

I don't know if there's a time lag (a startup time) between power-on and signal-transmit.

There is a time lag of at least 2 second on power up due to MIOS issuing an Upload request. So as it stands this is a non-starter because MIOS will wait for 2 seconds before the application is loaded. If you don't mind keeping you foot on the switch for more than 2 seconds every time you want to send a MIDI message, it should work...........but I'm sure you don't ;)

As lond as you avoid using a LCD in your MB the Current draw will be rather small, therefore your batteries will no be eaten to fast. I don't know the exact number of mA that the Core will draw with out anything else connected, but I would guess it is less than 100mA.