Hi Dave, It didn't twitch back and forth, it jumped (!) like it had a stepper motor !? I tried it on the Robbe servo tester and it seemed OK. T'other was still dead 🤔 Both servos are fairly recent. The jumpy one a mini Hitec HS-81, the dead one a Conrad (🤔) 8gm micro. If the dead one stays dead the insides will end up in my 'Useful bits' rack! I have a reasonable servo stock so it's not really worth spending much time repairing it. BUT I do like to know how things work and above all why they don't! Bonner: Did you mean the one with the 6 pin plug ? Can't ask the chap who gave me them, also Dave (!) an ex RN Captain I met at the Ostpark lake, I think he died about 10 years ago - RIP. We used to go flying over the Alps at weekends in his ancient Cessna, great fun BUT LOUD. My little daughter loved it 😊 The then wife you couldn't get within a 100yds of it! I don't expect any range problems either, 100yds to the other side of the lake to wake up the sunbathers (Whoop whoop!) is enough for me😉 Cheers Doug 😎 PS: think maybe I'll start a separate thread to continue this saga; testing and product review etc. Just like old times - designing and presenting Comms systems 😉
I wasn't sure that the Ultimaker original+ is still available but I just checked and it is at 995 Euros. It comes as a flat-pack with all the necessary pieces and, with mine, a free spool of filament. The frame is made from high quality ply wood and the quality and accuracy of the laser cutting is astonishing although you might need to ease a few of the joints with sand paper for a not too snug fit. I sealed my frame with cellulose dope floor a quick-dry finish. The electronics and stepper motors are easy to fit as is the setting up of the transmission components although the latter are a bit fiddly. All in all, it was good fun building the beast. Printing with it is easy, you download the Cura program which will build your G-Code files from an STL file and allow you to set up the printing parameters for the job. I've had a few disasters but generally get good results with PLA printed at 205 degrees with a bed temperature of 50 degrees. I've found PLA from Rigid Ink gives the best results but, to be honest, I haven't exactly 'played the field's with filament providers. One point in favour of Rigid Ink is that, once you are on their email distribution list, they will send you hints and tips for printing which is a boon as Ultimaker don't provide a pilot's operating hand book or much further reading on it. Would I get another one? Probably, yes.
Wayne I suspect it has to do with alignment. Many model boats have motors and prop shafts that are slightly out of alignment and benefit from a universal joint type connector that allows for this. Stepper motors and their loads are usually build to tight specs where the drive and load are in absolute alignment. I inherited a box full of similar couplers but with heavy springs in the middle (where yours have slots). The previous owner used to build his own equipment and was into mechanics and lathe work as well as electrics and model boats. If you can get the drive train in line I believe they should work. If you are considering using on your model a further post on the outcome would be great. Dave
Hi Wayne, thought I'd chip in on this thread when I saw the words arduino! The stepper motor mayyy need a stepper motor controller. Something cheap like a ULN2003 to go between the UNO and the motor. I'm not sure the direct outputs from the arduino UNO will offer sufficient current. Steppers can require quite substantial currents, especially if they stall or are told to "pause". There are some great libraries available for steppers too. I recommend the Adafruit library. Just make sure the correct pins are identified in the software. If it judders instead of rotates, it's most likely the wrong pins have been assigned to the wrong motor windings. If you get stuck, I'm happy to help with questions too 😁 Stephen
Hi Wayne The stepper motor on the actuator will require an Arduino or Raspberry to drive. I assume you will be able to replace with a brushed motor if you have neither. I also have an interest on model trains and we use small servos to operate the push rods for points. The retract switch on a Tx would provide the two positions needed by the servo. You are really cracking on with the project and the results are looking very impressive. Dave