I have built the following set up (see attachment) in order to have auto-trim adjustment on my control column. I have used a dc motor.I want it to be activated from pitch trim switches on the yoke, but if possible also activated or controlled by the autopilot.What is the best way of doing this with FSBus. (old version)David

>I have built the following set up (see attachment) in order>to have auto-trim adjustment on my control column. I have used>a dc motor.>>I want it to be activated from pitch trim switches on the>yoke, but if possible also activated or controlled by the>autopilot.>>What is the best way of doing this with FSBus. (old version)>>DavidI have no idea about how to do this with FSBus, but there is a very easy way to do it with a Phidgets 8/8/8 or 0/16/16 interface board (using DC motor). I can give you more details if you are interested.By the way, I really like the 'mechanics' of your idea. Looks simple & very workable.

Thanks Maurice.I'd be happy to have all input, suggestions and options.David

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>Thanks Maurice.>>I'd be happy to have all input, suggestions and options.>>DavidDavid,I am very busy the rest of this week, so I'll get something ready by the end of this weekend if all goes well. I have a clear vision in my mind about how to proceed but I need to draw a schematic so that things should be as clear for you as they are for me (hopefully)Hang in there :-).In the meantime, here is a bit of an explanation about how to use the Phidget interface boards. I am referring now to the 8/8/8 interface board. The US distributor of Phidgets has a cockpit simulator division. If you go there, you can download their free software which was created by a flight sim enthusiast & guru as well. You can also download the full manual and that manual is very well written and explains a lot of things about interfacing & how to use the Phidgets cards for various flight sim functions. No programming is necessary and it allows you to control various functions such as switches, led's, servos, LCD displays etc.. http://www.phidgetsusa.com/fs/cockpit_simulators.aspI am using the 8/8/8 board and their servo board in the 737 throttle assembly which I am currently building (about 80% done). With these boards, 3 servos and their software, I have been able to set my flap positions (no switches, just one pot), my throttle handles move when the A/T is on, the spoiler handle deploys the spoilers on landing. I am now working on the trim wheel and this is the biggest challenge mechanically speaking since there is little space to install a DC motor to turn the wheel.Which brings me to your question. What you are trying to do is a bit similar to what I need to do for my trim wheels. This is where the 8/8/8 interface board becomes very useful. You can use 2 or the digital outputs to control your motor. The program allows you to specify that any 2 digital outputs can be true if there is a change in the elevator trim control (0BC0 offset). If the trim (offset value) is changing in a positive direction, one of the output is true; if the trim is changing in a negative direction, the other output is true. If the trim is not changing, both outputs are false. In simple terms, a true output can be used to turn on a relay which provides power to the trim motor in one direction and the other output can provide power to the same motor in the opposite polarity & direction. With a DC motor which can change directions if you reverse the polarity (not all DC motors can do that), you should be able to move your yoke back & forth using the method you proposed. I have tested this concept with 2 LEDs connected to the 2 outputs. When I trim nose down, one of the LEDs lights up and when I trim nose up, the other one does. When the autopilot is controlling the airplanes, I can see the LEDs taking turns lighting up in response to the A/P commands. When the trim is not changing, both LEDs are off. So, the concept works and all that needs to be done is use the outputs to turn on one of 2 relays to provide the appropriate power to the trim motor. This is where my schematic will make things a bit clearer for you.What I wrote above may sound quite complex depending on your current knowledge, but believe me, it is not nearly as bad as it may sound. If you want to try that route, you should order their 8/8/8 interface board and with any switches, pots, LEDs you will easily understand how to control various flight sim elements. As I said at the beginning, I can make a wiring schematic that will make things much clearer and I will post it sometimes in the next few daysRegards,

Thanks Maurice, looking forward to it.

Here is the circuit wiring. Nothing is too critical here. Any medium power NPN transistor will do. The supply voltage for the relays will depend on the relays you choose. I would suggest a low voltage (5-12v) relay. Make sure the contacts are rated for the maximum current your trim motor can draw. The voltage for the trim motor should be whatever the motor requires.Hope this helps,Maurice

Thanks Maurice. It appears that I should be able to use this principle with FSBus as well.Any FSBus users have any input on this?David

>Thanks Maurice. >>It appears that I should be able to use this principle with>FSBus as well.>>Any FSBus users have any input on this?>>DavidJust keep in mind that this circuit will only work if any 2 digital outputs can be true if there is a change in the elevator trim control (0BC0 offset). It does not matter what the value is as long as it is changing. So, you'll need to find out if FSBus can give you similar outputs otherwise my circuit won't work for you.

Can any FSBus users comment on this?Yoss, can you answer this?David

Hi DavidHmm i think the digital out board is needed to implement that in fsbus and may be the same consept can be used for auto throttles Unfortunatly i didnt have builded such card so the easy way to check the consept is to try asighn some leds in Fsled card and see how that worksAlsow with some addional electronic, like in published circuit,may be possible to connect relays even to fsled led card Anyway worth to try Let us know if you did came out with some positive resultsRegards

Forgot to addAlsow simple ccc implementation may be needed to for false -true outputs logic as Mauricio mentioned So if thats will work with Fsled --rest can be solved by some simple additionnal circuit for motor drive

Hi DavidSome results for youThats can be done --so far the test with fsled card is promissingWorks as surpose to --even without CCC however will have to master some electronicsand connect dc motor to this cardof course the motor has to be geared as well as we dont wont rapid infuence on the trimm rotary--otherwice thats will couse alitude oscilatingSo still some work and tests to do

Thanks Yoss. Look forward to your input. So this circuit can be triggered by the FSLED board?David

Yoss,Did you do any further work on this project. My understanding is that the FSled card works on a matrix system so it is never constantly alight (I may be wrong). Is it on enough to keep the trigger for the relay circuit?ThanksDavid