Hey All, DarkSpectre here. Now that Cam has Iona shell kits available and that Jim at Hyperdyne is at the moment out of stock of his incredible PKE electronics package, I thought that It would be cool to start a thread discussing possible alternative components for the PKE electronics. My hope is that this thread will answer questions that DIY-ers will have.
Here’s what I gather one would need for the electonics
3 LED chaser kits (1 for the screen and 1 for each wing.)
RC Servos (can the wings be controlled by 1 servo or 2 smaller servos?)
Servo Controller?
Square LEDs for the face plate.
On/Off switch
Green Gel sheet for the display screen
So with that in mind let’s see if we can come up with some thoughts on how each would work, how it would be pieced together and where we can find the parts.
Some of the questions I would like to know are:
how do you program the servo(s)? Does it involve a computer or is it as simple as turning a screw on the servo itself?
How would you rig up the chaser kits? Would they all be wired together or would you use one of the control boards for the chaser kits to run all 3?
If a servo controller is needed, where would one be found?
I hope this starts off what I would like to see grow into an in depth forum.
I’m trying to remember what I learned in High School, but I think you can have just one light board. Make a simple sequence using components, not programming (as an assignment, I had to make a circuit that counted in binary. Similar idea).
As for the servo motor, I think you just have to make a simply board, and have it run for a certain time when activated.
I’m a little amazed at how expensive and complicated the Hyperdyne kit is, because the effects look quite simple. Though I probably couldn’t do it now.
Nope you need to supply it with PWM (Pulse-width modulation)
A pulse width of 1.5 milliseconds = center, with 1 millisecond and 2 milliseconds = left and right (left and right are relative to the orientation of the servo)
And this pulse needs to be sent every so oftern so the servo doesn’t time out, generally in the range of every 20-40 milliseconds…
Every brand servo is slightly different though the 1-2 millisecond swing is only guide some servo require a little more or less for full swing…
The wing chasers are easy it’s the same 4017 circuit shown in the public cyclotron schematic…
It’s not beyond the DIY’s abilities but it’s not going to be easy unless you understand what you are doing…
You make a PWM timer circuit… Most people today use microcontrollers, but it can be done with timer ICs as well as long as you can design a stable and accurate enough timer circuit…
I used a gear box I custimized from 2 lego gear boxes you just had to run a motor one way or the other.And for the lights I ran them all off one board that I cut down to fit and a lot of wires.
This is going good guys. I appreciate the post so far. I hope that other proppers out there are getting something out of this as well. gbfreak, the lego concept is really interesting to me. Could you go into a little detail as to what parts you used and how you put it together?
You’d think the Iona shell had unlimited space with all the crap we throw in there!
With regards to the lego motors, my SLK wings do come with the interlocking gears that can essentially eliminate one of your servo’s/motors (whatever you decide to use). Trust me, the less thats packed in there the better. Its a stretch just to fit the Hyperdyne kit in, so space is worth its weight in gold with regards to the Iona.
I was thinking of something similar, Cam. I was thinking though that if you used the Technic gears you could essentially do away with the servos all together. The wings would be manually raised and lowered using a gear as a thumbwheel. You could put a gear the the bottom, run one of those black shaft pieces to another gear that would interlock with the wings. I know that it would take more effort to make the wings move but you would have greater control and almost unlimited angles from the closed postion to full extend. Plus you can get a set of Technic shafts and gears for about 15 bucks. That would definitely minimize clutter. So hypothetically, if you used the manual wing system and bought some cheap chaser kits, you could bring your PKE to life for about 50 bucks, That’s pretty bad ass. And to tell the truth, before I researched the PKE, I always thought that Harold Ramis manually raised the wings anyway.
I just kinda noticed your intrest sorry. If you still wanna know how i did it let me know and I will take some picks of the lego system, and try and point you in the right direction part wise.
gbfreak, that would be great! I’m still going crazy trying to think of other ways to make this damn thing work :lol: Does any one on here know if an interval timer would work to control servos? like this:
I’m working on a PKE using a dule servo driver from servo city.com. it uses two knobs to control two sevos. I’m going to but a rack and pinion gear in between the two, so i can turn one clock wise, and the other counter clockwise in one motion. also check out this web site: http://www.allaboutcircuits.com/vol_6/chpt_7/6.html. This little lesson device could easily be adaped to our needs. just wire multiple leds to each peg, for the wings and desplay, and replace the 1 mega ohm resistor with a variable resistor (potentiometer) to control the speed.
Why not use just one servo and rig up a gear set for the wings, or use a gear/track set up so you can save some space.
Don’t forget that there is limited space in the shell, and there needs to be clearance for the wings to open and close with absolutely no obstructions… This gives you about 3/4 inch of play in each half to get all your electronics, servo’s, wires, switches etc mounted and working. If you look at my prop pictures, you can see two pics of the installed electronics. THe set up uses one small screen board, and one long main dirver board, combined with 2 micro servos and all the cables/switches etc… and this was still a big stretch to get it all in there with room for the wings to open and close freely.
Good rule of thumb when building a PKE… make the innards as simple and small as you can, it may all “fit” inside, but don’t forget the annular space that 2 moving wings takes up.
I was looking at that servo driver and I wonder if you can swap out the 2 potentiometers for 1 push button. The unit itself is not very big but the fact that you’d have to turn 2 knobs to make the wings move would suck a lot. I did however see that servocity also offers for 40 bucks a servo controller and the software to run it for 25. And if you went by Cam’s suggestion and use only one servo you could have the have the wings moving for less then 100 bucks(towerhobbies.com has servos from 7.99 to 17.99)
Cam, how would you go about using only one servo? I mean how would the servos and gears be placed in conjunction with the gear teeth already on the wings you sell?
Also has anyone given thought about instead of the waterfall display for the screen what about 1 centered LED that would blink more rapidly as the potentiometer is moved. It would be kinda like a motion tracker blip. I was thinking that that would look pretty sweet behind the green grid. Plus from a DIY stand point it would be easier to contruct. Granted it wouldn’t be accurate. Just a thought.
Keep it up guys, we have got some really good ideas going
Found a new way of doing the PKE electronics. It was cheap for me because I used stuff I already had, but it might not be cheap for others…
Anyway, I have a Disney World monorail electric train set. For those of you who don’t know, the monorail has two “wheels” that straddle the track; the electric train I have is capable of going in both directions…hmm.
So I took it apart, and guess what? There is a small, perfectly engineered gearbox that has a bunch of gears designed to make two wheels sticking out of the top of it turn towards each other (or away from one another), exactly like what you’d need for PKE wing movement. It’s controlled by a gear hooked up to the shaft of a small motor, which is wired to a DPDT switch. To those of you who don’t know, you can easy set a DPDT switch to reverse the polarity of the circuit in question. So there’s your up and down motion, no servos or pulses or anything required. all I really need to do is buy a momentary rocker switch that’s DPDT (the one on the monorail train set is a normal DPDT switch), wire it up to the motor and hook it all up to 2 AA batteries. Then buy the gear accessories lego technix kit (it’s like $10 from their website) and do a gear reduction to slow down the wing speed. From there all that’s left are the lights (easy to do if you know how to set up a timer circuit, which is just a 555 IC connected to a 4017 timer - you can google this and find tons of tutorials) and making the faceplate and wings…
…ok, so it’s still a chore. But at least it’s feasible (for me)
