Monday, August 3, 2015

2015-08-02 (Su) Wrist Mounted Chording Keyboard

Plans were made for a thumb board which would hold three buttons. Three raised nodules were modeled which would each hold a buttons and designate a particular distance between them. Holes for the bolts were spaced the same as the receiver piece modeled previously. Holes were angled to allow countersunk bolts for lower clearance and a cleaner look. Eight small holes were added to the design which do nothing more than reduce the amount of plastic necessary. Removing these holes can be done by downloading the OpenSCAD code and commenting the holes out.

Revolving shot 1
Revolving shot 2

A print was made and buttons were set on top of it. Once glued the buttons should be secure but the design should be changed to include a divider between the switches instead of relying entirely on the glue. While holding the keyboard and adjusting the position it seemed more logical to angle the key levers up rather than down. Angling them down suggested a relaxed feel but the hardware will likely rest lower down than the wrist rather than in the palm.

Print with switches resting on top

Fingers on keyboard with key levers angled up

To do:
  • Revise model and reprint
  • Add electronics
  • Figure a way to mount
  • Figure a way to move hinge pieces
  • Make model and OpenSCAD code public
  • Write keyboard code

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2015-07-28 (Tu)

Sunday, August 2, 2015

2015-08-01 (Sa) Wrist Mounted Chording Keyboard

Changes from version to version have been getting less dramatic. The built in spacer and axle were good additions and have been kept. A thick piece of plastic to press the tactile button was not necessary so it was reduced. Bolt holes were widened slightly to make assembly easier. The angle on the pieces was also increased to make a more relaxed fit.

A cone and peg were added to the flanged spacer. The flanged spacer was meant to be glued to the key lever arm piece after printing so it could be used as a pulley for deploying the lever arm. Ideally the lever arms would be automatically folded and unfolded as the keyboard was ready to be used or put away. The cone was meant to keep a pair of strings in line which would pull one direction or the other in order to deploy or retract the lever arms. If not needed the peg can be cut off and the cone ignored.

Rotating view of model

Print of model with hardware. Old versions in the background

To do:
  • Revise model and reprint
  • Add electronics
  • Figure a way to mount to wrist
  • Figure a way to move hinge pieces
  • Make model and OpenSCAD code public
  • Write keyboard code

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2015-07-27 (M)

Saturday, August 1, 2015

2015-07-31 (F) Weekly Summary

It's been a while since I narrated a video. There was no fancy microphone and I didn't rehearse as much as I could have but it turned out acceptably for a quick video, less than two minutes. All the functions I wanted to duplicate from the commercial reader I installed in my car were translated plus a security feature not found in the commercial versions.

Completing this project wasn't like the others because it hasn't been implemented. Future projects will be able to use this code and hardware to quickly build an RFID project. Implementing a servo, which will be likely for making a deadbolt turner, would be simple. Making another car door unlocker actually has enough programming already.

Video describing RFID authenticator

A new project was started which will hopefully turn into a piece of wearable tech. A handheld keyboard has been on my mind for a few months and after a night of intense brainstorming I had the idea to make collapsible keys which press on inexpensive switches. Making each collapsible key identical meant that a single design could be refined and repeated without having to build a completely custom design for each finger. The idea was sketched, modeled, printed, and tested.

Brainstorming sketches

First model
Scissoring motion of collapsible key

After playing with the first switch, which printed in white, three more were printed in black. A long threaded rod and locknuts were used to hold everything in place. A hole was drilled in the back and a second rod was used to secure the keys from spinning. The keys were printed to be the same size as standard keyboard keys and the spacing was laboriously done with locknuts to make them the same distance apart as keyboard keys. A second version was made which used a more convenient bolt size for the axle. Four copies were printed.

First printed keys

Comparison to standard keyboard keys

Second prints with more convenient bolt size

A third version was modeled which used a built-in axle so the key lever, blue, would not rest on the rod holding it together. The plastic it rides on was part of the receiver body, green. A spacer, purple, was modeled to keep the key lever seated properly. The modeled spacers were important since a single bolt and a single lock washer could be used to secure the parts while the key lever could move freely and no finicky measurements had to be maintained.

Third model revision

The rest of the weekly summaries have been arranged by date.





This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

Friday, July 31, 2015

2015-07-30 (Th) Wrist Mounted Chording Keyboard

Several changes were made to the model to fix a list of problems. Instead of relying on a carefully placed lock nut to ensure easy movement on the key lever arm an axle was crated on the receiver piece. The receiver piece was the one which had two bolts in the previous version. The axle was mated with a large hole in the key lever arm. To alleviate difficult alignment issues a hole was modeled at the back of the receiver piece and spacers were built into the pieces. At the rear hole a column was added which acted as a spacer for the next piece. For the front hole, the common axle, a flanged spacer was modeled. Flanging was needed to keep the key lever arm moving perpendicular to the axle.

Rotating view of updated pieces

Print of assembly side 1

Print of assembly side 2



To do:
  • Revise model and reprint
  • Add electronics
  • Figure a way to mount
  • Figure a way to move hinge pieces
  • Make model and OpenSCAD code public
  • Write keyboard code

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2015-07-26 (Su)

Thursday, July 30, 2015

2015-07-29 (W) Wrist Mounted Chording Keyboard

A support rod was added to the back of the pieces in parallel to the common axle. This support rod was added by drilling through all the pieces and adding nuts as the rod was pushed through the holes. Adding rods produced a sturdy structure and allowed the keys to press easily but adding rods was tedious and required time consuming alignment.

Rear support rod and common axle

Changes were made to the model so the axel would use a common bolt size, #6. This allowed for less specialized hardware which was easy to find and less expensive. Simple flanged spacers were purchased as well which added distance between the pieces without the need for numerous lock nuts. For a common axel a long #6 bolt was run through the axle holes, washers, and flanged spacers. A nut was placed on the other end and left loose, a lock nut would be ideal. This arrangement produced reliable button presses.

Easy to assemble version with inexpensive hardware

To do:
  • Revise model and reprint
  • Add electronics
  • Figure a way to mount
  • Figure a way to move hinge pieces
  • Make model and OpenSCAD code public
  • Write keyboard code

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2015-07-26 (Su)

Wednesday, July 29, 2015

2015-07-28 (Tu) Wrist Mounted Chording Keyboard

Four copies of yesterday's model were printed. Two colors of filament were used because the first cartridge ran out. Metric hardware was purchased for the first unit which tested well so long  hardware was purchased to go through each of the holes to act as a common axle.

Four printed parts

Pieces held together with common axle

Another view of common axle

Measurements for the pieces were based on a standard keyboard. Key sizes and spacing were measured on a standard bluetooth keyboard so it would feel natural. The angle given to the lever arms, shown below hanging off a table edge, was arbitrary and will likely change. Button function worked well so long as the backs of the assemblies were held stationary, like the table edge. The common axle was difficult to attach sine numerous locknuts had to be installed, the model will need to be updated.

Pieces were operational

Key size and spacing compared to a standard keyboard

To do:
  • Revise model and reprint
  • Add electronics
  • Figure a way to mount
  • Figure a way to move hinge pieces
  • Make model and OpenSCAD code public
  • Write keyboard code

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2015-07-24 (F)

Tuesday, July 28, 2015

2015-07-27 (M) Wrist Mounted Chording Keyboard

Modeling was done for the pieces. Pieces had to fit together to make a hinge and maintain clearances while collapsing and allow a neat fit while the pieces were opened for typing or closed for storage. While modeling live animation was used to ensure the pieces would fit together and operate as expected. Animation like this can be seen in the third image. Previous images were shown with pieces rotated to show how they would be printed rather than how they would fit together.

Each pair of yellow and blue pieces are the mechanical parts necessary for one finger key. One keyboard will have one key for each finger and three keys for the thumb. Planning has not been done for the thumb keys. Key sizes for this project were measured from a standard keyboard, 15mm squares, and will be arranged in a row with spacing the same as a standard keyboard. Final versions will may have customizable features which will allow keys to be moved to accommodate the resting location of each finger.

Flyby view of pieces
Spin view of pieces

Animation showing piece interactions

All modeling was done in OpenSCAD. OpenSCAD provided a parametric method which allowed for easy changes to be made for future builds. Bolt sizes were first input as 6mm diameter, then 3mm. American stores don't stock as many metric bolts as imperial measurement sizes and 4-40 bolts fit in a 3mm hole well but #6 bolts will likely be used in the next print since that hardware is easy and inexpensive.

To do:
  • Print parts
  • Add electronics
  • Figure a way to mount
  • Figure a way to move hinge pieces
  • Make model and OpenSCAD code public


The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.
Completed projects from year 2



This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2015-07-22 (W)