james111333

Thanks, yeah, I'm using a pre built hall sensor assembly that is in the form factor of a potentiometer. It has a sensing angle of 60 degrees andappears to have excellent accuracy (much more than what is needed for DCS I gather?) It was about £14 delivered and I couldn't be more happy with my purchase, it works perfectly with the Leobondar board. As I mentioned above, I'm still seriously considering the dampers. Does the pull resistance feel the same as the push resistance?

Do you have a link for the damper you used please? My current design uses a brass / nylon friction clutch to adjust resistance but I see that a lot of people use struts. Can the oil struts be adjusted?

Yeah, I've looked into the heat issue and have read that using a ceramic resistor of suitable resistance will help limit the heat in the magnet itself, also the magnet will be housed in a 10mm thick steel plate that is about 100mm x 150mm so that should hopefully act as a large heat sink. The resistor arrived today but I'm still doubtful on the reliability of the cheap Chinese magnet! I had also considered a push/pull solenoid that I could mount underneath the base which could have something like a bicycle brake pad attached to it as the friction face, I think this would be more reliable but a little clunky in design and execution. I'm working on another 3D plan at the moment so I'll post a video later but ideally I'd like to keep it as clutter free as possible. Slightly off topic from the collective but my threaded adapters turned up today that my friend turned on a lathe for me. Essentially they are temporary ends that will allow me to make a prototype cyclic extension out of 40mm bathroom waste pipe. I'll then send it down to him to use as a pattern to make one out of steel or aluminium.

Just for the hell of it, here is a video I took this week of a Merlin taking off at Lympstone Commando, I was about 20 meters away and it was awesome, I actually lost balance slightly right as the debris starts flying round in the scene :thumbup: love it.

I have a few updates on the project. I've not had as much time as I'd like to crack on with it due to a mixture of family commitments and having been seriously ill with meningitis which is still getting in the way of regular life! Possibly the most progress has been made by identifying the 60 odd wires going connected to the relatively large number of buttons these Merlins have. In total, I have the following: 8 momentary push button / toggle switches 1 trigger 2 hats 2 momentary rocker type switches (Similar to the red thumb rocker on the warthog throttle) 1 lever switch with on, off and stow positions Apart from one or two switches, most of the cables are duplicates, I assume for redundancy, one in particular is the 'Emer Jett' button (under the yellow and black guard) has 6 red wires going to it and is totally independent of the others, I assume this is Emergency Jettison but it would be good to find out it's intended use. Anyone know any pilots from 846 or 845 squadron? (UK Navy / FAA) I've got these wired up and working with my Leobondar board which works a treat, it's awesome actually as the collective has gold plated pin connectors which slot in perfectly to the control board as if they were made for it. Next up is the hall sensor / potentiometer, this great bit of kit recommended by Sokol1_br is fantastic. I could only get the 60 degree one at a sensible price so I will be gearing it accordingly but the accuracy is spot on and I played with it in DCS and achieved really fine control of the collective just by turning it manually on my lap. This leads me to my next question though. Does anyone know the travel in degrees of a collective? I need to check back as I may have asked already but I don't know how much travel a real collective should have? I'd be grateful for any input on this. I'm currently liaising with my engineer friend who will be machining the components of my design and he has suggested that I use an oil lubricated brass bearing with machined faces which will allow fine adjustment of friction by tightening some super fine threaded bolts. I was going to use regular bearings but the friction adjustment may be over complicated if I take that route. I will also incorporate an elctro magnetic brake and brake disc so that I can lock / brake the collective angle in flight. It is basically the same as a car disc brake but instead of a caliper, I will use an electromagnet designed for picking up 10kg parts to clamp the disc and hopefully resist the torque from any droop that may occur. Again, I need to find out which button on the Merlin collective this should be mapped to, I'll then use a latching relay to toggle this 12v circuit on and off. The image above shows the magnet I received which unfortunately is a 2.5kg one that was sent by mistake so I'm currently trying to get a replacement sent. Can anyone confirm whether in real life the collective droops if not held in place? I assume it doesn't just sink immediately but I'm not sure if it stays put and if so, to what extent?

Thanks, yeah, I was watching it for a while and desperate to buy it but it was pretty pricey so had to keep putting it off until I snapped one day and went for it haha. I can't find any others at the moment so I'm hoping it's currently one of a kind. Thanks for the tip on the pot, however I had already ordered the Hall sensor pot that Sokol1_br mentioned. I'm currently trying different ideas for the bearing and friction adjustment and hoping to possibly chat to someone face to face who flys, I have a few leads that I am persuing but if anyone knows any pilots in Devon, please let me know!

Nice, I have to shoot off now but I'll take a look at your posts, do you have a build thread? Indeed, bits and bobs popping up lots, I got in trouble the other day though as I suggested that I bought a tail rotor for an ornament (if I could even get it into the loft where my cinema is) but it is the size of a front door so I might have to wait until the wife is out to sneak it in. Remember - It is easier to ask for forgiveness than it is to ask for permission:megalol:

Thanks, yeah, the cables are quite rigid but they're all terminated with gold plated connectors which I think I will be able to plug directly into my Male-Female cables I use on my Raspberry Pi. The collective will need moving like yours from time to time as it will actually be installed in the left hand well of a modular 3 seat sofa. A sim pit would be great but the room needs to maintain functionality as a cinema room too, I'll post pics below. Instead of a normal base with cusions, this sofa actually fits together like a jigsaw (Nabru sofas) so the base cusion has it's own rigid back to it, this means I can remove it and am left with a big open storage well which will house the mechanism. It should then be possible to fold away and replace the seat cusion for movie night!

Thank you so much, I've had a look and will be ordering the Hall pot today :thumbup: May I ask though, I have read of people having issues with calibration and loss of accuracy with hall sensors (such as mr_mojo97 above) does this all in one solution remedy the issues pepole have encountered? I'd hazzard a guess at yes and also the fact you've recommended it, it sounds like a great choice. I'm currently exploring gearing to turn the pot at either 2-1 or 3-1 times as much as the collective to increase the accuracy by using more of the travel on the pot. (I can only find a minimum of 60 degrees on the hall sensor pot) Does anyone know roughly how much a real collective has in degrees? Or even the length of the arch at the tip of the collective? With choosing a gear setup, would I be introducing backlash or inaccuracies due to imprecise cogs? I only ask as I am into astronomy and currently learning about astrophotography, one upgrade people make is to swap the gears on the tracking mount for a toothed belt and pully system. Will this be a more precise way of turning the pot? I understand there may be sideways pressure on the pot due to the belt tension but I would avoid this by mounting a bearing on the spindle of the pot to create a full axle instead of what would essentially be a stub axle with vulnerability to wear from sideways tension. My vernier caliper turned up today so I can start making the measurements required to adapt the Merlin collective :joystick: I have a friend who has access to all of the engineering tools needed so we'll be working together on the desing and getting a prototype up and running soon!

all sorted now, thanks, my thread appeared about 15 minutes after I posted this one. Cheers

On the Merlin there is a screwed on faceplate which looks easy to remove to access wires and test continuity, each switch is also screwed in with Torx bolts so can individually be removed / accessed so I'm hoping it won't take too long to identify the redundant wires. Although I couldn't bare to cut them haha, it's still a serviceable unit!! I know it won't ever fly again but I want to keep it in it's original state. I'm not sure what the Lynx wires were like but these are all braided and manageable, nothing like the wires I use for my Raspberry Pi, they're just a tangled mess.

Awesome, thanks, I'm just reading your thread now, seems like we have very similar ideas and hardware tastes :thumbup:

Thanks, I can't wait to get stuck in, I think the first job will be an hour with the multimeter and some masking tape to label all those wires!!

I have just started my first thread on here but can't see my posts, there is an image and YT video attached, is it waiting on moderator approval? Thanks, James

It has 16 buttons and 2 x 4-way HAT switches as well as 2 x self returning rockers (like the red thumb switch on the TM warthog throttle). There are about 40 wires coming from the buttons but I think that a lot of them are from discrete circuits on the helicopter whereas I will be using a common 5v across all of them and then simply toggling them to on or off with the buttons. Would the BU0836A 12bit Joystick controller will be the right choice to go for? The HATs seem to be more like 4 way up, down, left, right buttons so no way to engage two at a time like down/left or down/right etc so I assume these will be seen as buttons too. I am thinking the buttons and switches should be pretty easy once I have identified all of the cables but my next question would be; what would you all recommend for the highest accuracy to sense the angle of the collective? I guess my options are either a pot or a Hall sensor but I have only used hall sensors in the past for on off switching rather than a positional sensor. If the range on the collective is only say 60 degrees from fully open to fully closed, will I get enough resolution from turning a Pot through only about 1/5 of it's range? The other option of the Hall sensor is a little more unclear, as I'm not aware of how accurately it could sense the arc of the collective axle which will probably have about a 10mm radius so if the arc was say 20mm, would the hall sensor be in range of the magnet at all times? I haven't found out the required resolution in DCS yet but I'd like to get as accurate as I can. Will a pot be suitable given the limited amount of angle used? I know it is better to use as much of the pot's range as possible so I could consider gearing it down from the main axis so I get more like 270 degrees travel on the pot, the issue there though would be the additional engineering involved which I'd like to avoid.

So it's official, after many months of silently stalking this awesome forum, I've finally signed up to post so hello everyone! I figured I'd start out with a build thread to cover the design and construction of my helicopter collective. As of today I am the proud owner of a genuine RAF Merlin collective, I must say, the build quality is incredible, it makes my TM Warthog feel like a toy, especially the switches, it may even be more of a step up in feel and build quality than going from my x-52 Pro to the Warthog. The buttons and toggle's clunk is supremely satisfying. Here it is, I'm hoping it's the only one of it's kind at the moment (when I turn it into a USB device I mean) My plan is to connect it to a Lebodnar board and construct an axle base then using either a pot of hall sensor for the rotational position sensing but all this will be covered shortly, I think one of my main reasons for creating the thread was not to show everyone as much as to hopefully discuss various design options and throw ideas about as although I'm happy to execute the project, I still have a lot to learn so hopefully you guys will be kind enough to get on board share your experiences with achieving what we all set out to do. Here is a very quick and dirty initial plan for the mechanism. Essentially it will consist of a bearing mounted axle with a nylon disc fused to it, using finely threaded machine screws, I'd then be able to infinately adjust the clamping force to enable just enough slip to be moveable but still avoid drooping of the collective. I'd like to implement an adjustable counter weight to balance it but due to space limitations, I may not be able to do so. Or at least I may be able to have a short counter balance arm with a cutom moulded lead weight to take some of the required force away from the crude friction system. I have looked at adjustable slip clutches but these are quite expensive. I'll add to the thread very soon with much more info and to open up some discussions, I'm really keen in the meantime to read people's views on pots VS hall sensors for this aplication. mounting a pot will be easy but I will probably only use about 20% of it's 360 degree travel and I would like to think that the higher the resolution, the better. I love how insanely accurate my MFG crosswinds are and maybe a collective doesn't need that much accuracy but I still want to get it as high as possible. Any input would be awesome, including exactly what resolution DCS will recognise from a throttle or collective. Many thanks, great to meet you all, James