Oh - Just for your interest I also make my own PCB's for electronics.
I use Diptrace for design although likewise I have good reports from the Designspark suite as it can link into RS and get you BOM.
To make the PCB I use 'PCB in a Box' www.pcbfx.com You print you PCB image via a laser printer on to the shiny side of the transfer toner paper. Then with a hot laminator you transfer the toner onto a copper board. Then using water to take the paper off you are left with the toner on the board. An additional run with foil to seal the toner then you are ready to etch.. Can do a pretty complex board in about 10 mins
Redesigned the eye mech to work a bit better. The unique 45 degree outward tilt of the eyes (rather than facing directly forward) adds some unique challenges and prevents using standard mechs.
Just cut some test pieces on the laser, and this design looks like it will work great after a bit of refinement.
WOW.. That is beautiful. Q. Will the eye be able swivel left and right. I think I can see how by the turntable section at the bottom and what looks to be a shaft pointing downwards in the CAD screen. This is really getting me to investigate doing CAD/CAM a lot more.
The entire riser assembly on top of the center bearing rotates left/right at the central axis of the eye. The eye is supported form the side by the riser, which allows it to rotate up/down.
That small shaft you see coming from the bottom of the eye is the attachment point for the cable that makes the eye look up/down.
Much progress has been made on my CAD work for this project in the last week.
I have fine tuned the eye mech into something that works within the unique constraints of this character. The eyes are now canted at 40 degrees from the center of the head. The 5 degree reduction causes the eyes to face slightly more forward, which looks a bit better.
Unfortunately this does not resolve the issue of the back of the eyeballs being visible when the eyes rotate inward, which is why this eye mech design is so atypical.
The orange piece in the image below mates with all the vertical risers to keep them at right angles during assembly. Once the pieces are chemically welded together it will be slid off the top. Planning ahead for these types of assembly concerns is one reason CAD prototyping is so handy. My previous laser cut prototype confirmed the need for this type of assembly jig.
The eye mech will be bolted to the head plate with 2 bolts in the slots seen at the back of this assembly. These side-to-side slots alight with 2 front-to-back slots on the head plate. This means the eye mechs can be adjusted to align with the underskull and skin should things shift during assembly. I'm working with fine tolerances, but allowing for parts to adjust their placement during assembly is a good safety net.
There are also 4 small holes (in a diamond pattern) in the base of the eye mech plate. These line up with 4 identical holes in the head plate so the mech can be seated in its ideal fixed location prior to adjustment. This is helpful for 2 reasons. First it means the eye mechs have a good starting point during assembly, before adjusting everything. And second it will make sculpting easier. (see below)
My first full prototype of the head assembly will have 2 uses... to test assembly and confirm that everything works as desired, and as part of my armature during sculpting. The full assembly, complete with 3d printed dummy servos, will be at the core of my armature. This means the eyes and all hardware will be perfectly aligned in the sculpt. At any point during the sculpting process I can use depth probes to insure that there is enough clearance in the sculpt to allow for the thickness of the silicone skin, underskull, and internal space.
I've also settled on a design for the mechanical linkage that will handle head pitch and yaw movements. This design, much like the new design of the frame is based on a building system known as ActoBotics. This system will allow for quick construction, which is important for side projects like this where shop time is limited. While it adds significant costs, it has many advantages that made it the right choice for me right now. It will be lighter than the welded assemblies I was planning on, save me a lot of machining time, and provide an abundance of attachment points for some future modifications I have planned.
This design also includes a unique method for articulating the jaw, seen in the bottom left of the picture above. Part of the jaw hinges extend up behind the head on either side. These are joined by a shaft which, when pulled forward, will open the jaw with even force on both sides. This will be hand cable operated from inside the body. The cable for this mech will run up the neck, into the head, and through the 2 holes at the very top center of the head assembly.
I just placed a huge part order, so I hope to have some build photos soon.
Considering the time it take to make various brackets, and also trying to bolt them together this is a pretty good solution. They have a great range of bits and pi8eces. Not sure if they have a Australian distributor as the postage will be the killer for me.
Updated the design of the eyelid mechs. Started with the "standard" interlocking eyelid ring design and modified it to work with an eye that has a linkage at its base.
This will allow for good clearance on the bottom lid as the eye looks up/down.
These pieces were printed at a low quality setting for speed. Now that I know it will work as desired, I'll print out both mechs at a higher quality.
Spent all day at the local maker space working on the Skeksis project today. Started assembling all the ActoBotics parts and have most of the frame assembled.
Next step will be the control yoke and cable linkages for the head up/down and left/right.
Here's a quick update on lessons learned during this first assembly. Currently all points of rotation are using ActoBotics Swivel Hubs, which are not idea for areas like the neck where there is lateral load on the bearings.
I'll be swapping many of the joints out for ballbearings and shafts this weekend (if my replacement parts arrive)
This is how I initially planned to handle joints, but the Swivel Hubs are so much easier to work with. Unfortunately they just don't hold up to the load/forces.
I'm also going to start setting up the control yoke and cable linkages this weekend, so both the head and neck can be puppeteered for the first time.
It has been a while since my last update on this project, but there has been some good progress.
I assembled the main body/neck/head frame and attached all the cables and controls. With all linkages in place, the head and neck can now move. This has allowed me to do some basic performance testing, and I'm really liking the range of motion.
I brought the Skeksis up to the West Coast Haunters Convention in Portland last month to demonstrate its design/construction as part of a class I was teaching on creature suit design and construction.
While there we ran into our friend RJ Haddy from the SyFy series "Face Off," and he had a brief romance with the Skeksis.
Now that I'm back in LA, I've been finishing up the CAD design for the head mechs. Here you can see the components that will form the mechanical core assembly inside the head, laid out for laser cutting.
Once I assemble and test the mechanical core I will mount a version of it to the steel armature for the head/neck and start sculpting around it. This will insure proper positioning of everything (eyes, jaw, etc) and allow me to probe the sculpt to determine distance to the mechs. Can't wait to get sculpting!
I've started a list of all the changes I want to make to the CAD design for the core based on how the assembly process is going. Few adjustments to make fitting the servos easier, and some changes to add a bit more strength.
I will be live streaming many of my builds in the future at twitch.tv/VexFX/ (possibly on youtube's live streams at some point as well: youtube.com/c/VexFx) so you'll get to see more of my bench/shop. If you subscribe to the twitch channel you should get a notification when my stream goes live. An automated tweet is also sent to my twitter account when the stream goes live, as I discovered when I did a test stream on the 26th.
The live streams are a lot of fun as people can chat with me as I work and ask questions. They are also a good motivator for me to be more productive, and make working in the shop a bit more fun/social.
Based on my findings so far from assembling the first version of the head's mechanical core I've made a few design changes. Every piece displayed below in red has changed slightly. Every piece in orange will be a thicker (.25" rather than .125") material to add rigidity, and also may have other minor optimizations. I'll likely be making more modifications as I start mounting servos and other hardware.
Tonight I will be assembling the 2 eye mechs and working more on the mechanical core. As I mentioned in my previous post, most of my work sessions will be live streamed on twitch. Tonight's session should start around 6:00pm-7:00pm PST and can be viewed here:
On last night's live stream I was able to get all 13 servos mounted to the mechanical core for the head.
Here are some photos of my progress.
The outer jaw shaft clamps have also been attached, which means I was able to mount the jaw and test its movement last night, and it's working great. I removed the jaw prior to taking these photos as it's a bit hard to work on everything with it attached.
Tonight I will be live streaming again and working on mounting the Arduino micro controller, the eye mechs, and the head/neck mechanical assembly. If you click the follow button on our twitch page you can get notifications each time the shop live stream is activated.
I'll be taking the whole assembly (torso/neck/head/mech core) to an event this weekend in LA for local R2 astromech builders, so there should be plenty of good photos and likely video of it all in action.
I may also be live streaming Sunday when I have a client coming by the shop to work on some prosthetic appliances for a character makeup.
It's pretty good as you can control it using I2C, it has a constant PWM clock so the Arduino is not having to generate that all of the time, you can expand it if necessary. Lets you use the Arduino of working out How to move, rather than what to move every step of the way.
I tend to run with the smaller boards like the Arduino mini pro's or the Teensy's.
I really love the Teensy's as they have a larger code area, plus they have a 128k FLASH area where you can store large array's or data using the PROGMEM function.
Plus they can run about 96mhz so you don't have to worry re calcs or other functions.
And they are fully Arduino code compatible too, and about the same price as the 'original' Arduino's.
Be very interested to see how you are going to code the movements.
Been a busy weekend, but I was able to get a bit more done Friday. Eye mechs have been assembled and attached (with temp reference eyes), jaw has been attached, and I started testing the PWM control board.
The Adafruit PWM board works great for the giant analog servo, but it seems to have some issues with the micro digital servos. The digital servos all make a high pitch whine when idle (nomatter their position within their range), which is something they do not do when hooked up to my servo tester/programmer box. I may have to reach out to Adafruit if I'm not able to address that issue. I've also not had much time to troubleshoot any of this. I only had a couple hours Friday night before getting ready to go hang out with Star Wars droids all day.
I was also interviewed by Norman Chan of Tested.com on Saturday about the Skeksis project. I'll post a link when that is live.
And I spent all day today with a client designing a prosthetic character makeup. (more on that soon on another thread)
Hi Chris The servo whine would be the PWM update frequency. Normal servo's get refreshed every 20 to 25ms, however Adafruit's servo board can update much faster than that. That means that the servo's are constantly rechecking their position and thus the whine. If you can try dropping the frequency that will stop the whine The command is pwm.setPWMFreq(1000)
So experiment with that about 50 or 60 and then try upwards.
I'm using pwm.setPWMFreq(60); for the analog servo, and have tried everything from 60 to 1000 for the digital servos. One of the code examples says to use 300-400 Hz for digital servos, but that did not seem to do the trick either.
I've not tried any lower than 60 yet, so I'll give 50 a shot next chance I get.
Can't wait to start seeing some motion out of this thing!
Rather than building my own harness from scratch (which was my original plan), I'm using an off-the-shelf harness that is designed for marching band bass drum players. This harness is ideal as it matches the exact criteria of my previous custom harness design: Connection points at the chest and the waist, with the ability to distribute weight on the performer's hips rather than just their back, and is adjustable to fit different performers.
I'll also be able to use this harness on future characters as it will easily detach.
While this option is not inexpensive, it ends up costing less in the long run between materials and time.
With other costumes where you have a heavy animatronic head on top of the actor's head - I wonder how the help support that. Would there be straps acting as additional tendons for the back of the neck.
It might be an interesting video for Mark to do showing the different ways of supporting large and heavy head pieces.
I think in the case of a large head on top of (rather than in front of) the performer you would just have the head attach to the top front of the harness, and let the rigid nature of the harness distribute the weight down to the hips. I'm sure I'll be trying that at some point with another project.
I was thinking of something like the William suit from Underworld - where the actor keeps his head looking down so they can see. In that position the neck is bent.
Comments
I use Diptrace for design although likewise I have good reports from the Designspark suite as it can link into RS and get you BOM.
To make the PCB I use 'PCB in a Box' www.pcbfx.com
You print you PCB image via a laser printer on to the shiny side of the transfer toner paper. Then with a hot laminator you transfer the toner onto a copper board. Then using water to take the paper off you are left with the toner on the board.
An additional run with foil to seal the toner then you are ready to etch..
Can do a pretty complex board in about 10 mins
Just cut some test pieces on the laser, and this design looks like it will work great after a bit of refinement.
The lids will be 3d printed.
Q. Will the eye be able swivel left and right. I think I can see how by the turntable section at the bottom and what looks to be a shaft pointing downwards in the CAD screen.
This is really getting me to investigate doing CAD/CAM a lot more.
That small shaft you see coming from the bottom of the eye is the attachment point for the cable that makes the eye look up/down.
/Chris
I have fine tuned the eye mech into something that works within the unique constraints of this character. The eyes are now canted at 40 degrees from the center of the head. The 5 degree reduction causes the eyes to face slightly more forward, which looks a bit better.
Unfortunately this does not resolve the issue of the back of the eyeballs being visible when the eyes rotate inward, which is why this eye mech design is so atypical.
The orange piece in the image below mates with all the vertical risers to keep them at right angles during assembly. Once the pieces are chemically welded together it will be slid off the top. Planning ahead for these types of assembly concerns is one reason CAD prototyping is so handy. My previous laser cut prototype confirmed the need for this type of assembly jig.
Link to full version of image that shows more mechanical detail.
The eye mech will be bolted to the head plate with 2 bolts in the slots seen at the back of this assembly. These side-to-side slots alight with 2 front-to-back slots on the head plate. This means the eye mechs can be adjusted to align with the underskull and skin should things shift during assembly. I'm working with fine tolerances, but allowing for parts to adjust their placement during assembly is a good safety net.
There are also 4 small holes (in a diamond pattern) in the base of the eye mech plate. These line up with 4 identical holes in the head plate so the mech can be seated in its ideal fixed location prior to adjustment. This is helpful for 2 reasons. First it means the eye mechs have a good starting point during assembly, before adjusting everything. And second it will make sculpting easier. (see below)
My first full prototype of the head assembly will have 2 uses... to test assembly and confirm that everything works as desired, and as part of my armature during sculpting. The full assembly, complete with 3d printed dummy servos, will be at the core of my armature. This means the eyes and all hardware will be perfectly aligned in the sculpt. At any point during the sculpting process I can use depth probes to insure that there is enough clearance in the sculpt to allow for the thickness of the silicone skin, underskull, and internal space.
Link to full version of the image that shows more detail.
I've also settled on a design for the mechanical linkage that will handle head pitch and yaw movements. This design, much like the new design of the frame is based on a building system known as ActoBotics. This system will allow for quick construction, which is important for side projects like this where shop time is limited. While it adds significant costs, it has many advantages that made it the right choice for me right now. It will be lighter than the welded assemblies I was planning on, save me a lot of machining time, and provide an abundance of attachment points for some future modifications I have planned.
This design also includes a unique method for articulating the jaw, seen in the bottom left of the picture above. Part of the jaw hinges extend up behind the head on either side. These are joined by a shaft which, when pulled forward, will open the jaw with even force on both sides. This will be hand cable operated from inside the body. The cable for this mech will run up the neck, into the head, and through the 2 holes at the very top center of the head assembly.
I just placed a huge part order, so I hope to have some build photos soon.
/Chris
They have a great range of bits and pi8eces. Not sure if they have a Australian distributor as the postage will be the killer for me.
This will allow for good clearance on the bottom lid as the eye looks up/down.
These pieces were printed at a low quality setting for speed. Now that I know it will work as desired, I'll print out both mechs at a higher quality.
/Chris
Next step will be the control yoke and cable linkages for the head up/down and left/right.
/Chris
I'll be swapping many of the joints out for ballbearings and shafts this weekend (if my replacement parts arrive)
This is how I initially planned to handle joints, but the Swivel Hubs are so much easier to work with. Unfortunately they just don't hold up to the load/forces.
I'm also going to start setting up the control yoke and cable linkages this weekend, so both the head and neck can be puppeteered for the first time.
/Chris
The difficult part now is staying on track, as the parts to my new CNC machine were just delivered today.
If only I could somehow build both at the same time.
/Chris
I assembled the main body/neck/head frame and attached all the cables and controls. With all linkages in place, the head and neck can now move. This has allowed me to do some basic performance testing, and I'm really liking the range of motion.
I brought the Skeksis up to the West Coast Haunters Convention in Portland last month to demonstrate its design/construction as part of a class I was teaching on creature suit design and construction.
While there we ran into our friend RJ Haddy from the SyFy series "Face Off," and he had a brief romance with the Skeksis.
Now that I'm back in LA, I've been finishing up the CAD design for the head mechs. Here you can see the components that will form the mechanical core assembly inside the head, laid out for laser cutting.
Once I assemble and test the mechanical core I will mount a version of it to the steel armature for the head/neck and start sculpting around it. This will insure proper positioning of everything (eyes, jaw, etc) and allow me to probe the sculpt to determine distance to the mechs. Can't wait to get sculpting!
/Chris
Now it's time to assemble it, test it, and plan any future modifications.
Progress!
/Chris
Here is a time lapse of the assembly:
I've started a list of all the changes I want to make to the CAD design for the core based on how the assembly process is going. Few adjustments to make fitting the servos easier, and some changes to add a bit more strength.
/Chris
Plus the sneak peek at your workbench
I will be live streaming many of my builds in the future at twitch.tv/VexFX/ (possibly on youtube's live streams at some point as well: youtube.com/c/VexFx) so you'll get to see more of my bench/shop. If you subscribe to the twitch channel you should get a notification when my stream goes live. An automated tweet is also sent to my twitter account when the stream goes live, as I discovered when I did a test stream on the 26th.
The live streams are a lot of fun as people can chat with me as I work and ask questions. They are also a good motivator for me to be more productive, and make working in the shop a bit more fun/social.
/Chris
Tonight I will be assembling the 2 eye mechs and working more on the mechanical core. As I mentioned in my previous post, most of my work sessions will be live streamed on twitch. Tonight's session should start around 6:00pm-7:00pm PST and can be viewed here:
/Chris
Here are some photos of my progress.
The outer jaw shaft clamps have also been attached, which means I was able to mount the jaw and test its movement last night, and it's working great. I removed the jaw prior to taking these photos as it's a bit hard to work on everything with it attached.
Tonight I will be live streaming again and working on mounting the Arduino micro controller, the eye mechs, and the head/neck mechanical assembly. If you click the follow button on our twitch page you can get notifications each time the shop live stream is activated.
I'll be taking the whole assembly (torso/neck/head/mech core) to an event this weekend in LA for local R2 astromech builders, so there should be plenty of good photos and likely video of it all in action.
I may also be live streaming Sunday when I have a client coming by the shop to work on some prosthetic appliances for a character makeup.
/Chris
http://www.adafruit.com/products/815
It's pretty good as you can control it using I2C, it has a constant PWM clock so the Arduino is not having to generate that all of the time, you can expand it if necessary.
Lets you use the Arduino of working out How to move, rather than what to move every step of the way.
Enjoy
Dave
Here is the board I currently have: http://www.adafruit.com/products/1411
As far as I can tell it's the same as the one you linked, just as a shield rather than an external board.
Just soldered up the PWM controller and wired everything up.
/Chris
Looking great
Yes it is the same board.
I tend to run with the smaller boards like the Arduino mini pro's or the Teensy's.
I really love the Teensy's as they have a larger code area, plus they have a 128k FLASH area where you can store large array's or data using the PROGMEM function.
Plus they can run about 96mhz so you don't have to worry re calcs or other functions.
And they are fully Arduino code compatible too, and about the same price as the 'original' Arduino's.
Be very interested to see how you are going to code the movements.
Dave
The Adafruit PWM board works great for the giant analog servo, but it seems to have some issues with the micro digital servos. The digital servos all make a high pitch whine when idle (nomatter their position within their range), which is something they do not do when hooked up to my servo tester/programmer box. I may have to reach out to Adafruit if I'm not able to address that issue. I've also not had much time to troubleshoot any of this. I only had a couple hours Friday night before getting ready to go hang out with Star Wars droids all day.
I was also interviewed by Norman Chan of Tested.com on Saturday about the Skeksis project. I'll post a link when that is live.
And I spent all day today with a client designing a prosthetic character makeup. (more on that soon on another thread)
So much to do, so little time!
/Chris
The servo whine would be the PWM update frequency.
Normal servo's get refreshed every 20 to 25ms, however Adafruit's servo board can update much faster than that. That means that the servo's are constantly rechecking their position and thus the whine.
If you can try dropping the frequency that will stop the whine
The command is
pwm.setPWMFreq(1000)
So experiment with that about 50 or 60 and then try upwards.
Hope this helps
Dave
I'm using pwm.setPWMFreq(60); for the analog servo, and have tried everything from 60 to 1000 for the digital servos. One of the code examples says to use 300-400 Hz for digital servos, but that did not seem to do the trick either.
I've not tried any lower than 60 yet, so I'll give 50 a shot next chance I get.
Can't wait to start seeing some motion out of this thing!
/Chris
I'll also be able to use this harness on future characters as it will easily detach.
While this option is not inexpensive, it ends up costing less in the long run between materials and time.
/Chris
It might be an interesting video for Mark to do showing the different ways of supporting large and heavy head pieces.
Dave
/Chris