Toggle Switches, Push Button and Rotaries

The Basics

Most cockpits, mine included, start with just a simple toggle switch. These are easy to use, easy to mount to a panel, and easy to wire up. There are however, multiple different types of toggle switches.

Toggle switches are actuated by moving a lever back and forth to open or close an electrical circuit. There are two basic types: maintained contact and momentary contact.

Maintained contact toggle switches maintain the position to which they are moved or actuated. Momentary contact toggle switches do not. Have a read here for more info.

The types I used in my cockpit are;

OFF-ON: A simple two position toggle switch. One way is ON and completes the circuit, the other is OFF on the circuit is closed. There are 46 of these in the cockpit.

ON-OFF-ON: This is a simple three position toggle switch. The lever clicks into three positions, down is ON and one circuit is complete, middle is OFF the circuit is broken, up is ON and the second circuit is complete. Note that there are two seperate circuits, sharing a common ground. There are 22 of these in the cockpit.

OFF-(ON): A simple two position toggle switch, however the ( ) indicates that the ON position is momentary and the lever will not lock into place when you switch it. You push the lever up, and the circuit will be complete. When you let the lever go, it will spring itself back into the OFF position and the circuit will be closed. There is only 1 of these in the cockpit, the JTSN switch on the CMSP.

(ON)-OFF-(ON): Another three position toggle switch, this time momentary in both ON positions. It will stay in the centre OFF position, and will have to be held in the up or down position to complete either circuit. There are only 4 of these in the cockpit.

ON-OFF-(ON): Similar to the above switch, but only one of the positions is momentary. The lever will lock into the middle OFF and upper ON positions, but will need to be held in the lower ON position as it will spring back into the OFF position when released. There are only 4 of these in the cockpit, all on the CMSP panel.

I choose early on in my project to try to keep costs down, so not many of my switches are real milspec aircraft items, most are just cheap eBay toggle switches and rotaries. But if you are chasing absolute accuracy, there is a fantastic list of all the real switches in an A-10C, with part numbers and links, compiled by ED forum user Deadman right here.

I did make a few exceptions and spent a little more:

I sourced some real Cutler Hammer switches that were old and relatively cheap on eBay
I found some NKK locking toggles, again sourced on eBay
I have a real Honeywell Landing Light Switch, sourced from Digikey. It was about $85 AUD.

All of the better switches above follow the same principles of the cheap ones, they are just made from better quality materials and have a much better feel when actuating them.

This diagram shows the position and quantity of all the toggle switches in my A-10C Cockpit.

The very basic switch I use in all of my panels. Simple cheap OFF-ON toggle, and out of all the cheap ones I bought, these orange ones have the most solid feel to them. Only one has failed me so far, likely because I over tightened it. There are 46 of these in the cockpit.

A better quality OFF-ON S21AL locking toggle switch made by NKK. They lock into position, and you need to pull the lever outwards to unlock and move it. I bought these on eBay for about $10 AUD each, but it is very rare to find them that cheap.

These are the ON-OFF-ON three position toggles I used. I recommend you buy one each of a few cheap ones to experiment first, then get more of the one that feels the strongest. Some really cheap ones have a very weak stop in the OFF position, so it is very hard to turn the switch to OFF without going all the way to the opposite ON.

PUSH BUTTONS

Momentary push buttons are spring loaded, so when you push the button it will close the circuit, but as soon as you let go the button will spring back and the circuit will open again.

Latching ones will stay down when you push it and the circuit will be closed (on). Push it again and it will unlatch, the circuit will then be open (off). I used these on the circuit breaker panel in place of real circuit breakers. None of them are actually connected, they are just for show.

I have also used four pull type buttons on the Fuel Panel. These ones are latching, however you need to pull the button out to turn on, and push it back in to turn off.

This shows the position and quantity of all the push buttons throughout my A-10C Cockpit. The only latching ones I used were for the circuit breaker panel, and they are for show only.

This is a momentary push button. I used these cheap plastic ones all throughout the cockpit, with the only real exception being the external stores jettison and the downlock override button, which are high quality ones that cost about $20 AUD each.

Here is a view of two buttons mounted as the Signal Lights Lamp Test and the Fire Detect Bleed Air Leak Test buttons. The switch is mounted in the bottom layer, so the body of the switch is recessed in the panel instead of sticking out from it.

The circuit breaker panel. This is where all of the latching switches ended up, and only as placeholders for where the circuit breakers should be. They are not connected to anything and are only for looks. I will likely swap this panel out for some more realistic 3D printed ones later on.

These are the push-pull switches I used for the fuel Fill Disable Switches. Only four required for the entire cockpit. Cost about $10 AUD ($7.60 USD) each.

The four Fill Disable switches in the Fuel Panel

rotaries

Rotary Switches

There are 19 rotary switches in my A-10C. Most (but not all) are 12 position rotary switches like this one. They are cheap, easy to install and I haven't had a single one fail on me yet. There is a washer on top that has a small barb on it, you select how many positions you need on your panel, put the barb in the corresponding numbered slot, then install. The switch will now have a physical stop where you wanted it too.

One problem with using these 12 positions rotaries is that the angle of throw of the lever is 30 degrees, which means some of my panels differ from the real aircraft. I have also used these 10 position rotaries, the benefit of which is that the angle of throw is 38 degrees. 8 degrees might not sound like much, but on some panels it can make all the difference and look much more realistic.

There is one genuine 8 position grayhill switch is used for the CMSP, only because I had a real aircraft knob for it that i didn't want to go to waste, and it would only fit on the smaller shaft of the genuine part.

There are also two specialist 3 position rotary switches in the MFCD's, as the large ones simply dont fit.

I used these.

Rotary Encoders

There is a total of 29 rotary encoders in the cockpit. All the rotary encoders in my cockpit are cheap ones on eBay, like this one here. Encoders are like most car volume knobs, as in they freely spin but have a distinct click as you turn them. These basically send a pulse every time you turn the knob, and with the Leo Bodnar cards listed above you can attach them easily and use them for any knob in the A-10C cockpit. I use them for radio channel knobs, the HSI and ADI knobs, all the intercom panel knobs and the ILS and TACAN knobs. They also have the added benefit of having a push button inbuilt in them as well.

Potentionmeters

There are 25 potentiometers in my cockpit, all of them cheap eBay ones like this. Potentiometers have a smooth turn, with a hard stop at the start and end position. They connect to the analog inputs in a Leo Bodnar BU083X, or to an Arduino analog input. There are different types, and the ones you want to use in a cockpit are called 'Linear', or with a 'B' prefix. I use 'B10K' pots on both Leo Bodnar cards and Arduino with no issues at all.

This diagram shows the position and quantity of all the rotaries throughout my A-10C Cockpit. Most are all volume and brightness knobs.

All up in my A-10C there are 19 rotary switches. Most are 12 position rotary switches like this one. There is a washer that sits on top (not pictured) that has a tab that you set to one of the numbers printed on the side. Once the washer is tightly fitted, the switch will have a hard stop at the position you selected.

Rotary encoders. All are the same thing, the only difference being the shaft type, and the PCB which makes connecting one to an Arduino much easier as it has inbuilt SMD resistors so you don't have to wire any up. I used ones with PCBs for all Arduino, and the plain ones connect direct to the Leo Bodnar BBI's with no issues at all.

Standard B10K Potentiometers used throughout my cockpit.

OTHER SWITCH AND BUTTON RELATED THINGS

These 'arcade style' 16mm push buttons were used for my Master Caution and NMSP 'Korry' style buttons. They come with a 24V incandescent bulb fitted, which i removed and soldered in a 3mm LED. I then painted and laser cut the front.

Front of the button removed. I soldered in a 3mm LED to the tabs inside, then painted the white part black before laser engraving the text i needed.

The Master Caution button fitted, I set it into the UFC so it is flush like the real thing, and it has an orange LED inside. Works well.

I used seven square buttons for the Navigation Mode Systems Panel (NMSP). Green 3mm LED's illuminate the buttons depending on what system you have selected, in this case EGI and TACAN. They are not true Korry Style switches as the text is supposed to remain illuminated, with only the triangle changing to show which you have selected. I may update this in the future.

I planned on using NKK locking toggles for the Armament HUD Control Panel (AHCP), but found that the force needed to unlock them made the entire front panel flex and made it feel like it was made of wood (which it is). I ended up using normal cheap eBay toggle switches, but hot glued on these aluminium tops made by lynx.dk to make them look real. It's one of my favourites.

I added this Pitot Heat top replica from lynx.dk to an NKK Locking Toggle for my Pitot Heat switch. I also bought a Steer Switch Top replica, a Manual Reversion switch top replica, and a Fire Discharge switch top replica.

Awesome products, but I bought these all before I had my own 3D printer!

The EGI and CDU switches are real Cutler Hammer mil spec switches I bought on eBay. Prices are ridiculous new (defence might pay $500USD for a single switch, but I wont!), but every now and then they pop up on ebay for cheap. I paid $50 AUD for an old C-130 panel that contained both. You can also see the 3D printed steer replica.

I bought this aluminium guard and a quality button for the External Stores Jettison button from lynx.dk. I spent a little extra money on this one, because it is prominent in the cockpit as its right in front of your face. Cost about $51 AUD, ($38 USD). Woirth the money, and definitely better than the crappy cheap one i had in there. And unfortunately, i use it a lot...