KLaFaille

Hi Ragtop, I know what you meant and I wasn't trying to correct you in any way, just throwing the info out there. :) Red

Just as more of a technical FYI, the A10 does not use a pedal setup like the F16 at all, in that the pedals are not connected and swiveling around a central axis. The pedals in the A10 are connected to hangers and rockers outboard of each respective pedal. Various pushrods and bell cranks are used to connect the pedals together and translate and invert the motion of whichever pedal is pushed onto the other. There is a crossover crank attached to a port side bell crank which actuates a pushrod going to an idler, which then goes back further to interface with more yaw system components.

The bezel appears to be brazed or silver soldered onto the front of the instrument can. There is a spacer used inside between the glass and the face of the instrument to keep the gauge assembly in place. The rear cover containing the the receptacle connector is high temp silver soldered into place, so you need a propane torch when opening these style of instruments. I'll see about getting some pics eventually. Red

Yes, technically that Ng should go away as the gauge is implemented in the A-10. A bit of paint maybe, or I'll just be lazy and leave it. Red

Wait, you mean you haven't designed and built your own stepper control board too? You designed everything else you need. ;) Seriously though, thanks for the info, I'll have to do some searching around and see what I can come up with. As an aside, SIOC and opencockpits stuff is yet another area where I have zero experience, much like most everything related to this cockpit undertaking. Things are starting to click here and there and it's always fun learning new things, though it seems like the more you learn the less you know sometimes. :D

Thanks, Canon 5D w/ 35mm f/1.4L anywhere from wide open to about 5.6 on one or two I guess, generally around 2.0 - 2.8 though. K

@Deadman, yeah you have to be wary of that "cold melt" hot glue sometimes. With these type LED, they don't drive that much current and only use about .074 Watts (Power = Voltage * Current or 3.7V * .02A = .074W) so they don't get too hot. Incandescents and the like though I'd probably stick with the take the flesh off your finger hot glue for sure. Oh hey, I snagged a proper real Oil Pressure gauge last night for $26, too bad that other % RPM went way too high for my liking. @Colin - I'll see what I can do. Once again it is amazing that something that seems so delicate and precise can handle the abuse that aircraft put them through. Red

Hey Niclas, When you mention an optical sensor to calibrate the steppers, I am guessing that you mean that there will be a bit of code that spins the stepper until an optical sensor detects that it is in the proper position to zero out the pitch and roll axises on the ADI? Red

True true. I did try something like that at first, but had no luck with it. I will do that method for the emergency panel, landing gear panel, and others with similar indicators. That's a good link to have in any case.

Hey there, here's a quick step by step of a way to LED backlight real instruments that start out as white incandescent, in this case a Percent RPM gauge. Gauge Backlighting (3 of 10).jpg by KLaFaille, on Flickr 1. Here's the gauge assembly removed from it's can. Next to it you can see the standard incandescent T1-3/4 lamp which is very common in aircraft components, and the hollow cylinder next to it is the housing the lamp sits in. Gauge Backlighting (1 of 10).jpg by KLaFaille, on Flickr 2. Here's the internals of the gauge. You can see towards the face of the gauge the rear of the lamp, the housing, and the copper plate that contacts the bottom of the bulb. There are three lamps wired in parallel so that if a bulb burns out the other two still work. One half of the lighting circuit goes directly to the gauge body itself, ground, while the other half goes to each of the three copper plates. Gauge Backlighting (4 of 10).jpg by KLaFaille, on Flickr 3. The lamp, housing, and LED we are going to replace the lamp with. Because the LED is smaller than the housing, we are going to use the leads of the LED to keep it in place in the housing and give us a good electrical contact. Gauge Backlighting (5 of 10).jpg by KLaFaille, on Flickr 4. Step one is to take the cathode (negative) leg and bend it flat against the base and back towards the front of the LED. Gauge Backlighting (6 of 10).jpg by KLaFaille, on Flickr 5. Next we wrap the cathode around the body of the LED. This is so the LED will sit snuggly inside the housing and you get a good electrical connection to ground. You may have to trim off a bit of length so that you don't have any of the cathode overlapping onto itself. After we wrap the lead, the wrapped end of the cathode is soldered to itself. At this time you can better round out the cathode around the LED body and make sure it fits snug in the housing. Gauge Backlighting (7 of 10).jpg by KLaFaille, on Flickr 6. I used hot glue to "pot" the LED securely into the housing, both in the rear and around the front of the LED also. While the glue is cooling make sure the LED sits centered in the housing. Gauge Backlighting (8 of 10).jpg by KLaFaille, on Flickr 7. Take the anode (positive leg) of the LED and bend it 90 degrees flat against the back of the housing. Then take and bend it back over itself so you end up with something like in the picture. Gauge Backlighting (9 of 10).jpg by KLaFaille, on Flickr 8. Fill the gap left in the anode with solder. We don't have to go crazy but want enough so that we end up with a decent sized ball. Trim off the excess anode and file smooth any sharp edges left by trimming. We have basically made an LED lamp at this point that works on the principal electrically as the incandescents we removed. The cathode is touching the housing which goes to ground, and the anode is touching the copper plates supplying the positive voltage. Depending on the voltage you choose to power your lighting and the voltage drop of the LED itself you will need a resistor to soak up the excess voltage. In the case of the LEDs I used, they have a forward voltage of 3.7V, which is a bit odd for a green LED but that is what it is, and I will be supplying them with a 5V power supply. 5V - 3.7V means we need a resistor that will soak up about 1.3V so the LEDs don't go poof. I ended up using a 22 Ohm resistor which resulted with about 3.65V going to each LED. A caveat regarding LEDs in parallel. Generally the way the LEDs are wired in the gauge now isn't the preferred method. Ideally we would like to calculate the required resistance needed for each LED and put a resistor in series with each one. Wiring LEDs in parallel with only one resistor requires that all the LEDs have a very close voltage drop to each other otherwise a single LED may end up pulling more current than the others which could lead to a failure. I did a simple swap of incandescent to LED, and incandescent lamps don't care about voltage the way an LED does and given the limited room (and some laziness on my part) I simply kept the wiring the same. The end result: Gauge Backlighting (10 of 10).jpg by KLaFaille, on Flickr Hope this was helpful, Red

Here's a doodad I put together to hold the synchros that control the roll and pitch of the ADI. Parts are salvaged from the donor ADI and re-purposed to fit my needs. The little term board has all the connections in and out soldered to it and wired into little connectors. The three on the rear are for the signals going to the ADI, and the one on the bottom is the 26V in to feed the two synchros. The front should allow for easy gearing the interface between synchro and stepper motor. Synchro Assembly (1 of 4).jpg by KLaFaille, on Flickr Synchro Assembly (2 of 4).jpg by KLaFaille, on Flickr Synchro Assembly (3 of 4).jpg by KLaFaille, on Flickr Synchro Assembly (4 of 4).jpg by KLaFaille, on Flickr Red

Thanks. See the difference though, is that the stuff I have done looks pretty but doesn't do anything yet, you can actually fly the sim in yours! :thumbup:

LOL.. Well I guess that would make you familiar then... I watched some of the vids of the sims you have, very very impressive stuff! :beer:

Some of the best LEDs I have found for panel lighting are what are called "Inverted Cone LEDs". These have a molded in lens in the front of the LED which spreads the light out to the side in a wide dispersion pattern instead of mainly forward. You don't end up with bright spots on the face of the panel and get a nice even lighting almost like incandescent. They are somewhat of a pain to find, but not overly so. Just for general info, if you can find green LEDs in the 510-520nm wavelength, they are a good match for NVIS Green Type A. :) Pits looking good. You really got it together nicely. Red

Could be, I don't know enough about them to be sure but you are likely correct. It's a GE 8DJ81 series Percent RPM Gauge, FWIW, and I do believe it was feed off a tach gen. Edited to add that I opened it up again and I think I see what you mean by the drag plate. There is a rotating assembly driven by the coil in the rear which has on it two sets of magnets with a round copper perforated plate in between. As the assembly turns clockwise, looking from the face of the gauge, the plate turns counterclockwise and the rotation of the plate moves the needles. Very neat setup! K

The one gauge I've taken apart, a Percent RPM gauge, seemed to be a simple rotor & stator configuration, the faster the rotor turned the greater the deflection on the two needles. Niclas, you wouldn't happen to know these guys or have more information on their DTS would you? NovelAir AB Simulatorteknik Digital To Synchro (DTS) usb-interface Thanks

Yep, thanks for the heads up on the steppers Mike. Gearing these will definitely have to happen, you can see how touchy they are in the video. The video, and my twitchy sausage fingers, don't convey it that well but if you are very careful moving the synchro the motion of the ball is very smooth as it should be. I'm not overly concerned with losing speed due to gearing considering this is an A-10 not a super twitchy fighter so it should be able to keep up well with the sim, but I'll have to experiment to be certain. One thing I know for certain though, I'll be mounting the transformer pack on the rear of the ADI along with the static converters in a remote, sound deadened location. That hum is crazy loud in person and I don't have two turbofans behind my head to cover the noise. ;)

A better pic for reference: A-10C Cockpit (20 of 26).jpg by KLaFaille, on Flickr

Might as well post this here too: YUXa1ssfEIU Niclas, thanks for pointing me in the right direction! Scratched my head a bit and then after a few experiments it all fell together. Never had anything go so painlessly either, super simple. Do you have any thoughts appropriate stepper motors and interfacing options available to turn the synchros? They obviously don't need much torque, but definitely need precision as they are very touchy and the slightest movement sends the ball moving. I'm guessing you can get away with a slightly less precise stepper but up the precision overall with gearing? I'm totally new to steppers, so even just a general shove in the right direction would be appreciated. Thanks, Keith

Thanks! I have to give credit where it's due to Byrdling for pointing me in the right direction. Once he had mentioned that you could control it with synchros, I sat there and scratched my head a while thinking about it then took one that I had lying around and hooked it up and sure enough the ball moved. Now I needed some more synchros... I had a second (not an ARU-2B/A) Lear ADI of military origin made in 1960 that was brave to the end, even as I dremeled its once proud casing to get at its guts. Long story short, after three hours or totally stripping down the ADI, I had both of it's synchros and motor-tach-gens out and a bunch of nice spare parts, bearings, indicator movements, and gears that will come in handy down the road. Most importantly I came away with an even greater appreciation for the engineering and thought that went into these instruments. There is so much crammed into such a small package and just the way the thing works in general is super cool, especially considering it's all analog, no digital wizardry involved. Anyways, I took the two synchros from the now deceased ADI, put them in the vice, and wired them up. I made sure that everything is isolated electrically, and hit the switch. No smoke or flames! Apart from having the black leads mixed on one synchro it all worked right out the gate, I really couldn't believe it. Took the vid, and that's where it's at right now. As Byrdling stated, the synchros will be slaved to stepper motors to interface this in the future. Should work out good. I'll likely still build a couple of Mike's boards because a) I have more synchro instruments to drive and 2) I don't have any more spare ADI's lying around to tear apart. ;) Red

Sorry panelbuilder, I couldn't help myself. ;) YUXa1ssfEIU I'm guessing everyone knows what this is by now. 28VDC -> Static Inverter = 115V 400Hz AC -> ADI Converter + 26V 400Hz AC -> Two control transformers (synchros). Synchro outputs go to the ADI and control the ball. Red

Hi Niclas, Haven't talked with you in quite a bit, hope things are going well. I have another ADI that I could strip down for the two synchros and I have a third one I pulled out of a simulator altimeter, and my KGS inverters can natively supply 26V 400Hz. I'd be interested in hearing details about a non D/S solution even if just for reference / educational purposes. Question though. Would the non D/S solution support controlling both the pitch and roll of the ADI ball with just the three synchros? Mike: Thanks for pointing out the update to the D/S project. I also saw that you now posted your board layouts for download which is a big help. I did some pricing last night, if I were to acquire everything that I need for two controllers from DigiKey it'd be about $125, the transformers being about $45 dollars of that. Even when adding the price of the boards being produced the project isn't cost prohibitive at all. Red

[Youtube]qjAHqqNzM1g Fiddling some more with my ADI and powering it up for the first time with a KGS static inverter. The static inverter is taking 28VDC and turning it into 115V 400Hz AC. This is then fed to the ADI, where it goes through the transformer pack with converts the 115V into the required voltages for the internals. The humming is the KGS Inverter and the ADI converter. Next step is to try and work out stabilizing the ball and build some digital synchro interface controllers. I've had three aircraft static inverters for months now, I just finally decided to throw some power to the ADI and see what would happen. Red

Nothing too exciting but I figured I'd share here too. qjAHqqNzM1g Red

Hi Mike, Thanks for that post. Scott's work is first rate and his end product is indeed a fine example of ingenuity and craftsmanship. Also, it's good to see you here and I want to personally thank you for what you have contributed to the home simulator community. I have your books and they should be required reading for anyone looking to build their own pit, they are an incredible resource. Between the chapters you have written on synchros and controlling them, and another member here who has great knowledge on their use, I hope to get my ADI running and interfaced at some point when time permits. Thanks again, Keith