What Switches do I Need?

[Rocky_53 1,579]

I've just completed the build on my new generic cockpit. All the panels are plug and play, eg, GoFlight switch and button panels, CPFlight MCP and EFIS, Propwash Radios etc, so for someone like me who is completely in the dark about wiring up my own customised switches and buttons, it's a bit of a challenge. I have a single panel I want to now buld which is to house primarily, a flap lever, parking brake and landing gear. I will add a few additional toggle switches also. So far I have bought after talking with Simon, a Leo Bodnar card, wire and a USB cable. The only thing I now need are the switches and here is where I become unsure... I have seen straightforward toggle switches, are these just on/off?  I have seen on/off/on-mo, on/off/on, and also spring loaded too. Can anyone spread some light on this for me? The flaps switch I assume needs to be sprung loaded so I can click it upwards to increase flap, before it springs back to centre and I can click it again, the same for down too. Is the landing gear just a straightforward toggle switch on/off? and what is on/off/on-mo? Or is this all irrelevent when using LINDA as it's very flexible and offers different ways of assigning switches? Sorry to be such a noob but some help and advice would be very much appreciated. Thanks fellas. 

[hs118 707]

My recommendation would be to use SPDT, single pole double throw, switches as your most basic switch. The "DT" means that both switch handle positions have an defined output to the Bodnar card. For example, with a regular SPST, single pole single throw, switch you could define the "on" position as gear down but there would be no defined output for gear up. Of the 30+ toggle type switches in my cockpit, all but one is SPDT.  I do have 4 switches that are SPDT spring loaded to center for trim controls and lights test functions.

Using SPST switches can create synchronization issues between the switch positions in the VC and those in the cockpit hardware. If there is no defined output, FSUIPC can sometimes have trouble detecting the desired state of the control.

Of course, having 2 outputs from each switch takes more connections up on the Bodnar card but my feeling was it was worth the extra.

Here is my cockpit blog https://uchisworld.wordpress.com if there is anything there that can help you.

[Rocky_53 1,579]

3 minutes ago, yurei said:

My recommendation would be to use SPDT, single pole double throw, switches as your most basic switch. The "DT" means that both switch handle positions have an defined output to the Bodnar card. For example, with a regular SPST, single pole single throw, switch you could define the "on" position as gear down but there would be no defined output for gear up. Of the 30+ toggle type switches in my cockpit, all but one is SPDT.  I do have 4 switches that are SPDT spring loaded to center for trim controls and lights test functions.

Using SPST switches can create synchronization issues between the switch positions in the VC and those in the cockpit hardware. If there is no defined output, FSUIPC can sometimes have trouble detecting the desired state of the control.

Of course, having 2 outputs from each switch takes more connections up on the Bodnar card but my feeling was it was worth the extra.

Here is my cockpit blog https://uchisworld.wordpress.com if there is anything there that can help you.

Hi Yurei, thank you so much for your help, it is perfect and very much appreciated. This all makes sense and is perfect. Just one question, I am thinking I need a switch for flaps which is spring loaded, so when clicked up or down, it returns to the centre, thus allowing me to increase or decrease flaps in steps. What are your thoughts on this? Many thanks.

[hs118 707]

4 minutes ago, Rockliffe said:

Hi Yurei, thank you so much for your help, it is perfect and very much appreciated. This all makes sense and is perfect. Just one question, I am thinking I need a switch for flaps which is spring loaded, so when clicked up or down, it returns to the centre, thus allowing me to increase or decrease flaps in steps. What are your thoughts on this? Many thanks.

Yes, very doable with the SPDT spring loaded to center switches. I believe they are called ON-OFF-ON switches.

Something like this: SPDT Center Off Momentary Each Side Panel Mount (bgmicro.com)

Here are the folks I got most of mine from https://www.bgmicro.com

Edited January 7, 2021 by yurei

[Rocky_53 1,579]

2 minutes ago, yurei said:

Yes, very doable with the SPDT spring loaded to center switches. I believe they are called ON-OFF-ON switches.

Here are the folks I got most of mine from https://www.bgmicro.com

Thanks so much Yurei. 

[MarkDH 234]

21 minutes ago, yurei said:

My recommendation would be to use SPDT, single pole double throw, switches as your most basic switch. The "DT" means that both switch handle positions have an defined output to the Bodnar card. For example, with a regular SPST, single pole single throw, switch you could define the "on" position as gear down but there would be no defined output for gear up

I respectfully disagree. SPST (ON_OFF) switches work just fine and each switch has two distinct states (on and off) so there is no ambiguity. Most of my cockpit switches (~200) are of this type. ON-OFF switches are managed explicitly by FSX, FSUIPC, LINDA, P3D and MSFS. For reasons unknown X-Plane 11 doesn't allow you to map OFF events (or maybe it does now, I haven't used it for ages) but you can do it with SPAD.neXt for X-Plane. Synchronization with a hardware cockpit is a possible argument for switches that can be read on startup, but I am not aware that any sim actually does this. I wrote my own Lua sync program in LINDA to read and sync all the switches on startup.

Howard, an ON-OFF-ON switch has three positions. It is essentially the same as the flap switch you described, except it isn't spring loaded so it can remain in one of three positions. Electrically speaking it is two switches, so you would connect it to two different inputs on the Bodnar board. In my Twin Otter, there is such a switch for the voltmeter and load meters to indicate for the Left Generator, the Right Generator and the Battery (bemtre postion). The starter switch is a spring-loaded version of the same switch, so the appropriate starter runs while you hold it left or right. I would guess if you see a switch described as 'ON-OFF-ON/mo', the 'mo' probably means the same as spring-loaded ('momentary').

[Rocky_53 1,579]

2 minutes ago, MarkDH said:

I respectfully disagree. SPST (ON_OFF) switches work just fine and each switch has two distinct states (on and off) so there is no ambiguity. Most of my cockpit switches (~200) are of this type. ON-OFF switches are managed explicitly by FSX, FSUIPC, LINDA, P3D and MSFS. For reasons unknown X-Plane 11 doesn't allow you to map OFF events (or maybe it does now, I haven't used it for ages) but you can do it with SPAD.neXt for X-Plane. Synchronization with a hardware cockpit is a possible argument for switches that can be read on startup, but I am not aware that any sim actually does this. I wrote my own Lua sync program in LINDA to read and sync all the switches on startup.

Howard, an ON-OFF-ON switch has three positions. It is essentially the same as the flap switch you described, except it isn't spring loaded so it can remain in one of three positions. Electrically speaking it is two switches, so you would connect it to two different inputs on the Bodnar board. In my Twin Otter, there is such a switch for the voltmeter and load meters to indicate for the Left Generator, the Right Generator and the Battery (bemtre postion). The starter switch is a spring-loaded version of the same switch, so the appropriate starter runs while you hold it left or right. I would guess if you see a switch described as 'ON-OFF-ON/mo', the 'mo' probably means the same as spring-loaded ('momentary').

Ah ha Mark, thanks so much for your input. I am at this moment looking for the relevent switches so advice very much appreciated. 

[hs118 707]

1 hour ago, MarkDH said:

 I wrote my own Lua sync program in LINDA to read and sync all the switches on startup.

 

Mark, 

This is the difference. It is not an insignificant effort. Particularly for someone just starting out.

Just noting how important this can be when using SPDT switches.

[MarkDH 234]

1 hour ago, yurei said:

Mark, 

This is the difference. It is not an insignificant effort. Particularly for someone just starting out.

Just noting how important this can be when using SPDT switches.

I agree, it's a pain. But do any of the sims actually read the switches on startup and set the virtual ones accordingly?

[oemlegoem 29]

It is not so evident how switches are defined. So maybe some more explanation.

A spring loaded switch position is described often as mom ,  or (on). Example, a 3 position switch as you would use as trimming switch could be described as mom-off-mom, or (on)-off-(on), but never on-off-on.
This switch has 3 contacts, the centre contact being 2. The switch in rest position is in the off position and no contact is made. The spring loaded (on) or mom positions then make the contact 1-2 or 2-3.
This is an easy example.

You have to be more careful with switches for a simple on-off function. A on-off-on switch has 3 positions, and you would not use that for a normal light switch that needs only 2 positions.

For a light switch with 2 positions, you would either choose a on-on switch which has 3 contacts, or a switch with 2 contacts.
The on-on switch with 3 contacts and 2 positions either makes the contacts 1-2 or 2-3. If 2-3 would be off, then if wired to a LeoBodnar, that off position is sent to the sim and e.g. X-Plane needs that to activate the light to go off.
Some manufacturers however could use a description on-none-on instead of on-on, meaning there are two positions but no centre position.

The light switch witch 2 contacts and 2 positions could be described as on-off or as on-none-off. Same thing. You could not use this switch in X-Plane and LeoBodnar without additional software like spadnext.

The term SPDT can be misleading. Without momentary function , it could be a on-off-on switch with 3 positions, or it could be a on-none-on (same as on-on) switch with 2 positions. The first one would not be suitable for a gear up/gear down switch because you do not want a center position without function for a gear up/down.

I would always recommend to look at the data sheet. See following examples from NKK and Knitter-Switch:
MtogglesBushing-334489.pdf (mouser.ch)
MTA 106 x.pdf (knitter-switch.com)

Mark, yurei: is it correct? Any comments? 

[MarkDH 234]

22 minutes ago, oemlegoem said:

Mark, yurei: is it correct? Any comments? 

All sounds about right to me :) I found Rapid Online a good source for switches.

[hs118 707]

2 hours ago, MarkDH said:

I agree, it's a pain. But do any of the sims actually read the switches on startup and set the virtual ones accordingly?

Not that I know of. My procedure is a cockpit state checklist similar to what the military uses and a script to set any Lvars to match the switch position in the checklist.

[hs118 707]

1 hour ago, oemlegoem said:

Mark, yurei: is it correct? Any comments? 

Great to see a thread like this on Avsim which has not been so rich with cockpit building dope.

Edited January 7, 2021 by yurei

[dogmanbird 269]

 

I know this is an older thread, but for those who stumble across it and are having difficulty with the operation of their switches, being intermittent or erratic when used with various microprocessor boards and the sim;

  ...some switches are designed to very briefly make contact with the new circuit, before breaking contact with the previous circuit, as the switch is thrown, while other switches are designed to break the previous circuit first, as the switch is thrown. If the switch has a datasheet available it may reveal it's workings. Some old tech terms were MBB (make before break) and MAB (make after break) type switches. I haven't seen it used much lately, maybe the terminology changed? MAB is generally desired for sim projects.

MBB - would result in, as an example, pushing a flap-up and flap-down button at the same time, as the switch gets thrown, thus possibly confusing the sim and having erratic flap operation.

In some cases the switch may be designed for MAB, but the lubricant used in some Chinese manufactured ones has been semi conductive, which caused the micro board to rapidly jump back and forth between two states as the switch is thrown. The symptom is generally most noticeable in low current circuits.

Checking for MBB/MAB can be tricky while testing a switch in an electronics store. Unless there's an obvious open circuit as the switch is thrown, it's not reliably tested with a multi meter, as sometimes the open circuit can be very brief on some switches and vise versa. Connecting both poles up to the microprocessor while connected to pc, and running one of the freeware joystick testing utilities with timing, will probably reveal what's really happening as it's switched, and will be seeing it happen with fairly low current.

So in theory, if its a good quality make-contact-after-breaking-contact type switch, and without semiconductive lube, it should work reliably regardless of whether it's single pole or dual pole, single throw or double throw.

The trick is, with the kazillion different asian manufactured switches out in the wild, how to know if it's good quality till you get it home to test🙂 

Edited April 14, 2021 by dogmanbird

[SergeyPe 92]

Honestly speaking, having made dozens of complicated simulator hardware projects I never came across MBB switches.

A couple of safe bets for the excellent MAB ones are C&K, Otto, Apem, Knitter, Honeywell & NKK. However all of them are quite expensive.

My advice would be to use the T80 series from Salecom- a Chinese brand that is manufacturing the clones (probably licensed) of C&K 7000 series. The life expectancy is 50K cycles and the build quality is practically the same as C&K with quite a reasonable price. I've used hundreds of them without a single failure, as opposed to various clones that look quite similar.