I have uploaded the sketch and Eagle files to the following location:
https://github.com/mrjohnk/Trackball
Monday, April 30, 2012
Wednesday, April 18, 2012
New Circuit Board Pix
By popular demand, below is a picture of the two extra boards that came with my order. The third one is happily running just fine inside my trackball module. I'm very pleased with the results.
Sunday, April 15, 2012
New circuit board arrived
The new circuit board arrived yesterday and it looks really nice. I was able to get it populated with parts today and it works perfectly. I made some slight modifications to the design before I sent this one to be created, so there was always a chance that I had made an error along the way. The changes included establishing digital and analog ground planes. The top side where all the surfance mount components are located has the analog ground plane while the bottom portion that is mostly bare is the digital ground plane. Hopefully that will improve the stability of the unit overall. I was getting some random lock-ups about once every day or two and I attribute it to having digital signal drains poluting my analog signals. We shall see.
Tuesday, March 27, 2012
New circuit boards ordered
After running on my own milled cirucit board for many months now, I have ordered a few from DorkbotPDX. I spent most of last night adding ground planes to both the top and bottom of the board and generally cleaning up the asthetics in preparation of sending it out for production.
While the my own milled versions work well for rapid prototyping, their longevity is a bit limited as I've had to resolder them a few times and fix broken traces. A few days ago, I had another lose connection that was the straw that broke the camel's back to get me going to have some professionally made. Heck it only costs a little more than $7 for three of them to be made, so it seems like a real bargain. Hopefully the professional grade ones come out like I hope and work. We'll see.
While the my own milled versions work well for rapid prototyping, their longevity is a bit limited as I've had to resolder them a few times and fix broken traces. A few days ago, I had another lose connection that was the straw that broke the camel's back to get me going to have some professionally made. Heck it only costs a little more than $7 for three of them to be made, so it seems like a real bargain. Hopefully the professional grade ones come out like I hope and work. We'll see.
Thursday, February 2, 2012
Sunday, January 29, 2012
Milling PCB Cover
Sunday, January 22, 2012
Grounding patch
The grounding patch is finished. It has two strips of velcro hook sewed on each end of the stretchy conductive fabric. I secured one side with the velcro, then gave it a stretch over to the other side and tacked the other side down as to make a nice smooth addition to the top. A wire is connected by crimping force under a metal gromet to connect the fabric to the Teensy board. In addition to providing a grounding patch, this is where I anticipate most of the wear to be happening, so it can be replaced at a later date without having to replace the whole hand support.
What is left? Well, all parts are done and working. I need to design and mill a new bottom cap on the track ball module as the current one is a little too short. Once that is done, I'm guessing it is time to start making some silicone molds of these CNC machined parts to be ready to reproduce them and make anther full trackball to prove it can be done. Once they are reproducable, I'm thinking I'll need to get a few in the hands of alpha and beta testers to see what needs adjusting.
What is left? Well, all parts are done and working. I need to design and mill a new bottom cap on the track ball module as the current one is a little too short. Once that is done, I'm guessing it is time to start making some silicone molds of these CNC machined parts to be ready to reproduce them and make anther full trackball to prove it can be done. Once they are reproducable, I'm thinking I'll need to get a few in the hands of alpha and beta testers to see what needs adjusting.
Friday, January 20, 2012
Showing Off Some Pictures
Over the past few days, I've made quite a bit of progress. The new hand support is a dream. I took some time today to tidy up the unit and get it ready for pictures. Long gone is the bread board and it is a self contained unit. Some pictures below:
Monday, January 16, 2012
New Hand Support Promising
This afternoon, my wife and I learned how fun it is to sew two pieces of 2mm neoprene material together using a common household sewing machine. It took a few trys, but eventually we got the tention setup right and learned a few techniques along the way. 4mm of neoprene is taller than the gap under the sewing machines presser foot, so it can be challenging. The new hand support is done. It looks and works great. It is filled with the sand and clay mixture and isn't leaking out. I couldn't be happier with the way it came out with a solid feel, yet moldable to fit your hand. The outside is 100% covered in Velro type loop that accepts normal Velcro hook. I pasted some "industrial strength" Velcro hook on the back of all the buttons and put them on there. They hold quite nice to the outside of the hand support and allow their removal and re-installation to the new hand support over and over again until you get each button in exactly the right place. We went with a very conservative stitch path that is pretty much just a rectangle and straight stitch. The next version will have a bit more curves and design flare with a zigzag stitch now that we know we can sew it. One of the secrets ended up being the use of tissue paper both above and below the neoprene to help it slip under the presser foot and feed. The neoprene by itself is quite stubborn and wants to hang up, causing it not to feed through the machine. Another tip learned is to stick the neoprene parts to be sewn together with double stick carpet tape. Pinning them together just doesn't work since the material is so thick.
One of these days I'll get around to posting some actual pictures, but my desk is just a mess with all the tools, wires and so on, so I have been reluctant.
Next up is the creation of the grounding patch that will sit atop the hand support. I received the small sample size Medtex180 material from SparkFun last week. It looks and behaves much like regular spandex type material with a nice shiny gleen on one side. I plan to use a small metal gromet that I bought at the local fabrics store poked through the material and hammered down nice and tight to make a soldering point. That should make a good solid connection without the requirement of an adhesive.
After the grounding conductive material is in place is to migrate the Teensy board from the breadboard over to its place on the hand support. I wanted to be sure we got the hand support nailed down before I started figuring out where the Teensy board would reside. In order to do this, I'll need to design a soldering template that will help me add some tiny 0603 size capacitors to all of the analog pins (11 of them) on the underside of the Teensy board; each run to ground. Using low value capacitors (100pF - 490pF) really helps make the capacitance touch events much more responsive and repeatable. While I can reliably detect touches without them, the are a little slower without the capacitors in place. I plan to glue them down with the hot glue gun to give them structural support to stay attached, in addition to being soldered to each pin the grounding wire running between all of them. They will all be covered over with a piece of Velcro hook that will hold the Teensy board to the hand support so nobody will know they are there.
One of these days I'll get around to posting some actual pictures, but my desk is just a mess with all the tools, wires and so on, so I have been reluctant.
Next up is the creation of the grounding patch that will sit atop the hand support. I received the small sample size Medtex180 material from SparkFun last week. It looks and behaves much like regular spandex type material with a nice shiny gleen on one side. I plan to use a small metal gromet that I bought at the local fabrics store poked through the material and hammered down nice and tight to make a soldering point. That should make a good solid connection without the requirement of an adhesive.
After the grounding conductive material is in place is to migrate the Teensy board from the breadboard over to its place on the hand support. I wanted to be sure we got the hand support nailed down before I started figuring out where the Teensy board would reside. In order to do this, I'll need to design a soldering template that will help me add some tiny 0603 size capacitors to all of the analog pins (11 of them) on the underside of the Teensy board; each run to ground. Using low value capacitors (100pF - 490pF) really helps make the capacitance touch events much more responsive and repeatable. While I can reliably detect touches without them, the are a little slower without the capacitors in place. I plan to glue them down with the hot glue gun to give them structural support to stay attached, in addition to being soldered to each pin the grounding wire running between all of them. They will all be covered over with a piece of Velcro hook that will hold the Teensy board to the hand support so nobody will know they are there.
Thursday, January 5, 2012
Grounding the humans
While troubleshooting some capacitive touch issues today, I discovered a major advancement. By grounding the human who will be touching the buttons, it makes detecting capacitive touches very much easier as there is a path to ground through the skin. Looks like I'll be needing to procure some conductive fabric to play with. As a test, I've just got some bare wires running over the hand support this evening and it is working great. I read over Jeff's write up over at Keyglove regarding conductive cloth. I'll need to find a source to get a little. It doesn't have to be all that stretchy as I'll be sewing it to a piece of velcro. The end-user will need to just paste it on the hand support somewhere it that it will contact their hand. The hand support will be made from material with velcro loop, so options are limitless.
Sunday, January 1, 2012
Arrival of the Pentabutton
I designed a new "pentabutton" before Christmas and finally got around to milling it out yesterday. I'll be working on the metal contacts to complete it sometime today. It should allow me to fully map out all 11 capacitive touch buttons. Buttons will include: 3 mouse, 2 scroll (up & down), 1 resolution selection, 5 user programmable keystrokes.
The new pentabutton is intended to be placed for your first finger and first mouse button. The mouse button being in the middle area with four optional programmable button pads around the sides.
On a side note, I'm awaiting the arrival of some neoprene material to make yet another hand support prototype. Making this thing work from an electrical and programming point of view was the easy part. Designing the look and feel seems to be the harder part of this project. I'll be contracting my wife to sew up the neoprene and help me out with the pattern making with her mad sewing skills.
The new pentabutton is intended to be placed for your first finger and first mouse button. The mouse button being in the middle area with four optional programmable button pads around the sides.
On a side note, I'm awaiting the arrival of some neoprene material to make yet another hand support prototype. Making this thing work from an electrical and programming point of view was the easy part. Designing the look and feel seems to be the harder part of this project. I'll be contracting my wife to sew up the neoprene and help me out with the pattern making with her mad sewing skills.
Friday, December 23, 2011
Screenshot of Triple Button
Since I have not posted any pictures lately, here is a screenshot from Alibre Design showing the "triple button" that is used for the middle mouse button. This was milled out using my Zenbot CNC router. The low areas with holes in them are where I have 22 gauge nickel metal contacts with wires soldered to their backs located. The holes are there to allow the wire to exit the back. At this point, the wire is the only thing that holds the metal contact inside the shell, but eventually that will be secured with an adhesive. For a size reference, the square area in the middle is 11.5 mm wide. Each smaller touch pad area is 5.5 mm tall. The dividers between the buttons provide tactile position feedback of your finger and are 1.5 mm tall.
You may also notice that my screenshot is looks different as I have now upgraded to Alibre Design 2012. They had one of those killer end-of-year upgrade offers I just couldn't pass up :p.
You may also notice that my screenshot is looks different as I have now upgraded to Alibre Design 2012. They had one of those killer end-of-year upgrade offers I just couldn't pass up :p.
Moving to millisecond polling and added keyboard strokes
In the past few days, I have almost completely re-coded the majority of the capacitive touch buttons detection code. Instead of counting CPU cycles, it is now based upon timetamps. Each button's polling rate can now be specified in milliseconds. This greatly helps manage CPU resources to ensure that each button gets the attention it needs without hogging up resources to do it. In addition, I added a key-to-pin mapping array that allows the pins to be remapped easily to whatever you want that particular button tied to a pin to be doing. These changes have added ease of use and increased overall performance to put CPU resources to use where it is most needed and stopped wasting CPU cycles on less important things.
Now, when I say whatever I want that button to do, I also made vast improvements here as well. Teensyduino allows the Teensy board to interface as a keyboard+mouse composite device to the computer. That being the case, I can now send both normal mouse clicks and keyboard strokes. I took extra care to be sure that I can send multiple keyboard keys pressed at the same time too, so now up to six buttons can be sent at the same time. As a test, I put a new fourth button on the trackball for my pinky finger to use and played WoW for three hours. I was able to map this to the F4 key and it works perfectly. I was able to ressurect fallen players while in combat with my pinky!
In addition to these changes, I have stopped development on the scroll wheel. The scroll wheel with it's opto-interrupters was working perfectly, however it was a bit on the large and bulky size. In place of where it would be, I simply designed a new middle mouse button that has smaller half-sized touch pads above and below the middle mouse button that allow for scrolling. Now that I can control the polling rate, I can control the scroll speed up and down the page which is awesome. A nice, neat and elegant solution to scrolling that has no moving parts and is ultra compact.
Now, when I say whatever I want that button to do, I also made vast improvements here as well. Teensyduino allows the Teensy board to interface as a keyboard+mouse composite device to the computer. That being the case, I can now send both normal mouse clicks and keyboard strokes. I took extra care to be sure that I can send multiple keyboard keys pressed at the same time too, so now up to six buttons can be sent at the same time. As a test, I put a new fourth button on the trackball for my pinky finger to use and played WoW for three hours. I was able to map this to the F4 key and it works perfectly. I was able to ressurect fallen players while in combat with my pinky!
In addition to these changes, I have stopped development on the scroll wheel. The scroll wheel with it's opto-interrupters was working perfectly, however it was a bit on the large and bulky size. In place of where it would be, I simply designed a new middle mouse button that has smaller half-sized touch pads above and below the middle mouse button that allow for scrolling. Now that I can control the polling rate, I can control the scroll speed up and down the page which is awesome. A nice, neat and elegant solution to scrolling that has no moving parts and is ultra compact.
Monday, December 12, 2011
Many small updates and fine tuning
It has been a while since my last update. In the last few weeks, I have tried an alternative hand support material made from sand and clay that I'm prototyping. I filled a regular balloon with the material and it is meeting the right requisites of being firm but moldable. It took me quite a few tries to get to this point with several failed attempts along they way including a cast silicone mat with copper wire running through it and even mini beach balls filled with air. I even tried using metal wire mesh, but none of those approaches yield an acceptable end product. The new sand and clay mixture is just right. The old sand and water prototype was slowly growing mold and needed to be replaced ASAP, especially since the prototype unit is my every day use trackball now. Even though it isn't complete, it is much more desireable to use verses the 20-year-old Logitech trackman I was using.
I have been working toward the goal of eliminating the outboard breadboard by migrating the components (processor, LED and scroll wheel) to the trackball area to create a self contained unit that only requires the USB cable. Currently, I have some stretchy Velcro (Velstretch it is called) on order that has promise to allow it to be attached to the hand support that can be molded into any shape. The Velcro will provide an attachment method for the various peripherials such as buttons, scroll wheel and the ball socket itself.
I'm also coming to the conclusion that I'll need a Velcro covered base plate that is about the size and shape of a mouse pad to mount all this onto. The ball socket and scroll wheel are kinda big and will need support from below to be stable. Currently, the prototype is making heavy use of double stick carpet tape to hold the parts together in place of where Velcro will eventually be.
In the last week, I also located some nifty nickle silver buttons that allow me to solder wires to. They make a nice finish on the capacitive touch buttons. To further dress them up, I milled out some plastic finger guides to go around the buttons to provide some tactile feedback regarding where the buttons are and guide the finger to the center of the buttons.
Yesterday, I put the finishing touches on a lighted capacitive touch button. It incorporates a tri-color LED under a nickel silver button. As you touch the silver button, the light changes, with an indirect reflection of light appearing around the edges of the silver button through some recesses. The prototype is milled from translucent polycarbonate, so the light is actually shining through the walls of the case, somewhat like a glass brick. It gives a nice low intensity glow from the LED. I may look for a translucent casting resin to reproduce this for copies. It looks really nice.
Also on order are various sizes of surgical tubing to act as conduits to route the wires. I plan to split them down the side and make a sort of rubberized wire loom out of them.
Lastly, I'm awaiting a delivery of liquid rubber coating I can use on the hand support and the base plate. Hopefully this will bring the search for a proper hand support module to a close if I can successfully encase the clay and sand mixture inside this rubber coating. It boasts the ability to simply dip the item to be covered into the mixture, slowly withdraw it and let it air dry. We'll see.
Lots of progress on several fronts, but not a lot fully completed. I'm still working on this about every day from making new CAD designs to milling the smaller detail items and circuit boards. Tonight was milling out the outter case for the scroll wheel. Tomorrow will be milling out an updated version of the scroll wheel supports with smaller screw holes and a few cosmetic updates.
I have been working toward the goal of eliminating the outboard breadboard by migrating the components (processor, LED and scroll wheel) to the trackball area to create a self contained unit that only requires the USB cable. Currently, I have some stretchy Velcro (Velstretch it is called) on order that has promise to allow it to be attached to the hand support that can be molded into any shape. The Velcro will provide an attachment method for the various peripherials such as buttons, scroll wheel and the ball socket itself.
I'm also coming to the conclusion that I'll need a Velcro covered base plate that is about the size and shape of a mouse pad to mount all this onto. The ball socket and scroll wheel are kinda big and will need support from below to be stable. Currently, the prototype is making heavy use of double stick carpet tape to hold the parts together in place of where Velcro will eventually be.
In the last week, I also located some nifty nickle silver buttons that allow me to solder wires to. They make a nice finish on the capacitive touch buttons. To further dress them up, I milled out some plastic finger guides to go around the buttons to provide some tactile feedback regarding where the buttons are and guide the finger to the center of the buttons.
Yesterday, I put the finishing touches on a lighted capacitive touch button. It incorporates a tri-color LED under a nickel silver button. As you touch the silver button, the light changes, with an indirect reflection of light appearing around the edges of the silver button through some recesses. The prototype is milled from translucent polycarbonate, so the light is actually shining through the walls of the case, somewhat like a glass brick. It gives a nice low intensity glow from the LED. I may look for a translucent casting resin to reproduce this for copies. It looks really nice.
Also on order are various sizes of surgical tubing to act as conduits to route the wires. I plan to split them down the side and make a sort of rubberized wire loom out of them.
Lastly, I'm awaiting a delivery of liquid rubber coating I can use on the hand support and the base plate. Hopefully this will bring the search for a proper hand support module to a close if I can successfully encase the clay and sand mixture inside this rubber coating. It boasts the ability to simply dip the item to be covered into the mixture, slowly withdraw it and let it air dry. We'll see.
Lots of progress on several fronts, but not a lot fully completed. I'm still working on this about every day from making new CAD designs to milling the smaller detail items and circuit boards. Tonight was milling out the outter case for the scroll wheel. Tomorrow will be milling out an updated version of the scroll wheel supports with smaller screw holes and a few cosmetic updates.
Saturday, November 19, 2011
Avago ADNS-9500 Up and Running
I spent most of yesterday designing, milling and building the new circuit board for the Avago ADNS-9500 chip. It took most of today to work through all the software changes required to make it work. It certainly has a much higher DPI capability that is pretty insane. Moving the ball just a little jumps from the edge of one screen all they way over to the edge of the other screen (using two computer monitors). I'm not sure I'll have much use for that in 5670 DPI mode, but it is there should I find a need for it.
From an electrical design standpoint, the ADNS-9500 is very similar to the ADNS-7550. Changes included a new physical package layout, grounding one pin to select between 5V and 3.3V and bumping up the size of one of the capacitors. Other than that, the two chips use exactly the same design.
From a software perspective, I had to make arrangements to download the SROM to the chip every time it boots up. My attempts at this were pretty bad and just crashed my Teensy board. After doing some Google searches, I found a sketch pre-made that worked like a champ. I was able to combine it into my current software to make a working version. I just updated the firmware software to the current version and all is working well. There were a few minor additional changes required to make this chip do all that I had ADNS-7550 doing, but the firmware download was the biggest hurdle. The key ended up being the need to store the SROM image in flash memory on the Teensy instead of the default SRAM since the flash has a much larger capacity.
In addition, I'm using the taller version of the ball support on this new circuit board with a wider set of metal ball support contacts. It is nice and silky smooth. The three metal supports contact the ball just below the equator line. It seems that the further I spread these out, the better the ball movement feels.
From an electrical design standpoint, the ADNS-9500 is very similar to the ADNS-7550. Changes included a new physical package layout, grounding one pin to select between 5V and 3.3V and bumping up the size of one of the capacitors. Other than that, the two chips use exactly the same design.
From a software perspective, I had to make arrangements to download the SROM to the chip every time it boots up. My attempts at this were pretty bad and just crashed my Teensy board. After doing some Google searches, I found a sketch pre-made that worked like a champ. I was able to combine it into my current software to make a working version. I just updated the firmware software to the current version and all is working well. There were a few minor additional changes required to make this chip do all that I had ADNS-7550 doing, but the firmware download was the biggest hurdle. The key ended up being the need to store the SROM image in flash memory on the Teensy instead of the default SRAM since the flash has a much larger capacity.
In addition, I'm using the taller version of the ball support on this new circuit board with a wider set of metal ball support contacts. It is nice and silky smooth. The three metal supports contact the ball just below the equator line. It seems that the further I spread these out, the better the ball movement feels.
Tuesday, November 8, 2011
Scroll Wheel Update w/Pics
Posting has been a little slow, but I have been busy every day working on this. Going into this, I knew that the scroll wheel would be the most mechanically complex portion of this project. All of the parts need to be made and fit together. I have the wheel itself and the supports on either side milled out so far. I'm working on the circuit board at this point and need to mill out the outer case.
The theory of operation is that there will be two photo transistors that will be picking up a reflected light pattern from a rotating code wheel. I found a nice little component (GP2S60) that incorporates both the phototransistor and emitter in a tiny surface mount package. It is called a photointerrupter, made by Sharp. A pair of these will be used to generate a quadrature signal that will indicate how fast the wheel is turning and in what direction. Being optical, they won't create any drag. I'm looking for this scroll wheel to be easy to move and have no detents, like all other scroll wheels do.
Below are some pictures from my CAD system showing the assembly of the scroll wheel:
The theory of operation is that there will be two photo transistors that will be picking up a reflected light pattern from a rotating code wheel. I found a nice little component (GP2S60) that incorporates both the phototransistor and emitter in a tiny surface mount package. It is called a photointerrupter, made by Sharp. A pair of these will be used to generate a quadrature signal that will indicate how fast the wheel is turning and in what direction. Being optical, they won't create any drag. I'm looking for this scroll wheel to be easy to move and have no detents, like all other scroll wheels do.
Below are some pictures from my CAD system showing the assembly of the scroll wheel:
The photointerrupters are shown in red and yellow. The circuit board will fit in the recess window on the right. Those photointerrupters will be surface mounted to it:
The codewheel is highlighted below. It will be a white piece of paper with a black set of stripes printed on it. Simply, it will be glued/stuck to the side of the wheel.
Tuesday, November 1, 2011
Better Optical Chips Arrived from Avago
Ask and you shall receive. I'd like to extend a big thanks to Avago Technologies for sending me samples via Fed-Ex of their ADNK-9500 kit. I only asked for the raw chips, but they sent the lenses and a CD too! Awesome! I can now start doing some designs based upon this new better chip.
Thursday, October 27, 2011
Better optical sensor, hopefully
I sent an email over to Avago Technologies today to inquire about where to obtain some ADNS-9500 optical sensors. None of the US distributors were stocking them, so they indicated they may be able to send me some samples. Hopefully I will be able to begin working with these to see just how good this can get. I really like the ADNS-7550 version I'm using now, but I'm eager to see their better chip in action. I'm crossing my fingers that a small package of them shows up.
In the mean time, I've taken a little break. The PCB cap needed to be redesigned with more internal clearance, but the milling of the new design failed...again. It is very frustrating having a small CNC router that is just not so good at prototyping these larger parts. Maybe one of these days I'll get my hands on a little more beefy CNC mill for doing these sorts of things...
In the mean time, I've taken a little break. The PCB cap needed to be redesigned with more internal clearance, but the milling of the new design failed...again. It is very frustrating having a small CNC router that is just not so good at prototyping these larger parts. Maybe one of these days I'll get my hands on a little more beefy CNC mill for doing these sorts of things...
Saturday, October 22, 2011
New Socket Milled & Hand Support Update
A day off of work does wonders for making progress on personal projects. Yesterday, I was able get the silicone hand support filled with sand and the latest version of the ball base socket milled. Fair progress.
In consulting with my wife regarding the hand support, we came to the decision that using oil instead of water would be best for the long term keep of the sand in the enclosed space of the hand support. We explored several different kinds of oils and we settled on a type that has a very long shelf life. I was drawing on her expertise as a soap maker, where oils of many kinds are used. We have many kinds in stock. So, the hand support is filled with sand and oil now. There is some air trapped inside which needs to be removed. I figure using a hyperdermic needle to suck the air out would be best, however, I don't have any needles handy at the moment, so that will be on the shopping list. The hand support feels like an oversized beanbag chair for your hand, extending all the way down to the wrist. It is very comfortable. Once the air is removed, it will firm up a bit.
The latest version of the ball socket was a long time in the making. I've had several setbacks that kept it from getting done. Most of the issues have been related to my CNC router. This successful version comes after five other failed attempts to create it. The failures all had a machining error of some sort or another. It all boils down to the fact that this is a tiny little CNC router with weak stepper motors and I'm asking it to do more than it was designed to do. After a 3.5 hour marithon session last night, I eventually got it done by running the machine at about 40% of the job speed. It made for a late night (I didn't get done until about 1:30 AM), but at least it is done. The piece was milled out of a polycarbonate block measuring 1.75" square and 0.75" tall using a 0.125" ball end-mill. The stepdown was backed way off to 0.01" per pass, so it took about 75 passes to mill down. This was a single-sided milling effort this time. None of my double-sided attempts were successful. I'll just have to manually locate and drill the eight holes on the underside with a template and drill press, so not so hard and probably the right way to do it anyway.
In consulting with my wife regarding the hand support, we came to the decision that using oil instead of water would be best for the long term keep of the sand in the enclosed space of the hand support. We explored several different kinds of oils and we settled on a type that has a very long shelf life. I was drawing on her expertise as a soap maker, where oils of many kinds are used. We have many kinds in stock. So, the hand support is filled with sand and oil now. There is some air trapped inside which needs to be removed. I figure using a hyperdermic needle to suck the air out would be best, however, I don't have any needles handy at the moment, so that will be on the shopping list. The hand support feels like an oversized beanbag chair for your hand, extending all the way down to the wrist. It is very comfortable. Once the air is removed, it will firm up a bit.
The latest version of the ball socket was a long time in the making. I've had several setbacks that kept it from getting done. Most of the issues have been related to my CNC router. This successful version comes after five other failed attempts to create it. The failures all had a machining error of some sort or another. It all boils down to the fact that this is a tiny little CNC router with weak stepper motors and I'm asking it to do more than it was designed to do. After a 3.5 hour marithon session last night, I eventually got it done by running the machine at about 40% of the job speed. It made for a late night (I didn't get done until about 1:30 AM), but at least it is done. The piece was milled out of a polycarbonate block measuring 1.75" square and 0.75" tall using a 0.125" ball end-mill. The stepdown was backed way off to 0.01" per pass, so it took about 75 passes to mill down. This was a single-sided milling effort this time. None of my double-sided attempts were successful. I'll just have to manually locate and drill the eight holes on the underside with a template and drill press, so not so hard and probably the right way to do it anyway.
Ball Base Socket (0.75" tall):
Ball Base Cap. It covers the circuit board that hugs the bottom of the Ball Base Socket (shown above). The hole in the bottom is for the eight wires that need to connect back to the microprocessor unit:
All components:
All Components, combined
Hand support shown next to the combined trackball assembly:
Sunday, October 16, 2011
Scroll Wheel - First Draft
I've spent most of today working on the new scroll wheel design. Now that the trackball, buttons and hand support all have working prototypes, I need to get the scroll wheel into protytype too. Below is the first draft. It is 1" in diameter and 0.375 wide. The slots along the side are spaced to match up with an Avago AEDR-8300 Series Encoder to act as the encoder wheel. This makes the wheel both functional to receive input from the end-user and increment the encoder. The goal is to minimize the footprint both in width and height as much as possible. An axel will be added through the middle and I'll have to mill out a support (think faris wheel), PCB mounting spot and some sort of case for it all to fit into.
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