Tuesday, March 31, 2015

2015-03-30 (M) Self Contained Haptic Distance Sensor

The first draft of the Arduino code was written. The code was written using the distance sensing code from a past project which was a Theremin-like device and used two distance sensors to calculate hand distance similar to a real Theremin which uses radio waves. Code from this project also filtered bad data from the readings so unreliable readings would be ignored or at least translated into data usable by the servo.

Screencap of Arduino code

Project files were made public through Dropbox. These files are duplicated from the working copies and not the originals which have file names which change to match the current date. I talked about this method of dates in May of 2014 during a failed 3D printer project.

Files for Self Contained Haptic Distance Sensor:

To do:
  • Design way for servo cam to push on user without rubbing
  • Print enclosure
  • Test for usability
  • Refine design
  • Write program for Arduino
  • Test device
  • Write instructions
  • Propose project for TCP for workshop
  • Make files public

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-24 (Tu)

Monday, March 30, 2015

2015-03-29 (Su) Self Contained Haptic Distance Sensor

A list of changes to the enclosure was made which corrected the known problems with the design. The 3D modeling and rapid prototyping saved considerable time and resources by comparing sizes in reality as opposed to virtually or mathematically. Real life sizes of parts were measured with digital calipers and translated to the model. While modeling, screen captures were taken so an animation could be generated which showed the changes in a brief format.

Changes:
  1. Shrink wall thickness from 3mm to 2mm
  2. Change post shapes from pyramids to cubes
  3. Revise lid
  4. Hold servo externally
    1. Add posts
    2. Use screws to attach
  5. Shrink and move logo
  6. Shrink interior size
  7. Remove diagonal screws from ultrasonic distance sensor footprint
  8. Add post to suspend ultrasonic distance sensor
Animation of modeling changes

To do:
  • Design method of holding the enclosure together neatly
  • Design mount for servo which uses screws instead of bolts
  • Design way for servo cam to push on user without rubbing
  • Model new enclosure and lid
  • Model enclosure 
  • Print enclosure
  • Test for usability
  • Refine design
  • Program Arduino
  • Test device
  • Write instructions
  • Propose project for TCP for workshop
  • Make files public

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-23 (M)

Sunday, March 29, 2015

2015-03-28 (Sa) Twin Cities Plus

On Saturday I was part of a roundtable discussion for Twin Cities Plus, a local non-profit for which I am the secretary.


If you  skip to 20:55 that is where the meeting starts. We'd love to find people to donate time and skills. Money is also accepted and we're a nonprofit charity recognized by the IRS so donations are good for everyone. Even leaving a comment on the YouTube video page would be appreciated.

Saturday, March 28, 2015

2015-03-27 (F) Weekly Summary

The 3D Printed Automatic Tea Maker was completed. During the process I found a web service which allows me to easily put 3D models online and you can look at the models easily. Thingiverse didn't offer anything as streamlined that I could find. The biggest hurdle of the project was to create the enclosure and 3D printed parts which was still new to me. But that was the point in this project: I wanted to teach myself about 3D modeling. There was a lot of wasted space in the enclosure and the footprint for the LCD screen wasn't totally accurate but the project came together. Not only did I learn a lot about the modeling but the project worked so it was ultimately a very successful project.





The tea maker ran as well as I had hoped. The interface is easy to understand and intuitive, at least I think so. Users turn the potentiometer to the desired time, which is shown on the screen and press the start button. If the they aren't sure what time to select the screen also shows the tea name. The video below shows the operation. The files necessary for someone to copy the project have been made public. To make understanding the project easier an Instructable was made which shows step-by-step how to make a copy.


Video of tea maker operation

Files for 3D Printed Automatic Tea Maker:
// COMPLETED // COMPLETED // COMPLETED // COMPLETED // COMPLETED

A new project was started. This project was based on previous distance sensors which translated distance to pressure through a servo. The version created by me was not trying to revolutionize or do anything new but instead was meant to make the project more accessible. With a 3D printer and some soldering a user could gain sonar sense in a very small package. The largest component was a USB battery pack. If the project is successful a workshop could be arranged so the skills and device could be spread to the community.


Animation of enclosure progress





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

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.

Friday, March 27, 2015

2015-03-26 (Th) Self Contained Haptic Distance Sensor

The first printing of the enclosure was meant as a draft copy which would require revision. Measurements were taken and parts were held up to it and laid inside to get an idea of how they could all fit together. Previous workflows without a 3D printer could not feasibly create an enclosure with the sole purpose of visualization in order to create future editions.

The ultrasonic distance sensor did not fit into the holes as designed by using internet resources. The spacing and sizes were nearly correct and the discrepancy may have been due to the printer's tolerances. The screw/bolt holes however did not match the model of distance sensor so measurements were taken and a second footprint was generated which matched the model used. The bolt holes were significantly smaller and the only size of bolt which could fit was 1.6mm which was fortunately available at a nearby hardware store. The second faceplate was printed as a thin piece which was merely meant to test the fit of the footprint. It fit well and also demonstrated the need to put a spacer between the ultrasonic transducers so the sensor would sit parallel to the plate.

Test faceplate with ultrasonic sensor

1.6mm bolts with sensor and faceplate

The servo mounting issue had not been addressed before the first enclosure had been printed. After holding the servo in different positions it was easy to see different ways of mounting it. The most efficient solution was reached after days of contemplation and involved keeping the servo entirely out of the enclosure and mounting it on posts extending from the rear cover. This will keep it opposite the direction the distance sensor faces so the components form a line. This will also shrink the enclosure size. No sketch or model has been made of this proposed shape. Measurements were taken to increase the likelihood that the next print of the device will be final. The servo horn attachment has not been tested but will not need to be reprinted unless it needs to be changed.


Measurements being taken

To do:
  • Design method of holding the enclosure together neatly
  • Design mount for servo which uses screws instead of bolts
  • Design way for servo cam to push on user without rubbing
  • Model new enclosure and lid
  • Model enclosure

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-21 (Sa)

Thursday, March 26, 2015

2015-03-25 (W) Self Contained Haptic Distance Sensor

The model was improved to include walls, a back cover, and a power cord hole which will probably be replaced with a port which will pass a coaxial power connector. The back cover was embellished with my symbol. The back cover also has four pyramidal posts which are meant to mate with the walls to ensure a tight fit. These posts may have to be moved in slightly to account for the error in printing.

All the work to the model so far has been compiled as an animation to better visualize the process. This animation was constructed by rendering images in OpenSCAD when any significant step was taken. The images were animated by importing them and exporting the layers as an animated gif. There are 300mS between each frame with a 5000mS delay on the last frame.

Animation of enclosure progress




 To do:
  • Design method of holding the enclosure together neatly
  • Design mount for servo which uses screws instead of bolts
  • Design way for servo cam to push on user without rubbing
  • Model enclosure

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-18 (W)

Wednesday, March 25, 2015

2015-03-24 (Tu) Self Contained Haptic Distance Sensor

One of the first Make Magazine projects which really caught my eye was two distance sensors hooked to two servos through a controller. The wrist-mounted device was instantly appealing because it gave wearers an innate sense of their surroundings. I am very interested in expanding human senses with technology such as the ESPeri.IRBud which gave a user information on temperature using an infrared thermometer or the magnet in my left ring finger and another one in my left index finger. The magnets allow me to sense magnetic fields like microwave ovens in the kitchen and powerful solenoids where I work.

This project aims to capture the functionality of the wrist-mounted device but make it more modular so it can be easily repurposed. This design could be applied in multiple locations along a person's arm or shoulders to give a better sense of surroundings. My goal is to make it so easy to build that people will come up with their own placements and uses.

Enough background.
----------

Modeling was done for a servo spindle which would apply varying pressure to the user depending on rotation. The hole in the middle is meant to attach to a servo horn and may need to be adjusted so that reasonable pressure is applied. Most importantly this is a cam which does not attach a disc to its center. Since the servo will rotate the piece from off center the piece will extend further and further as it spins which will apply more and more pressure. Since the pressure should be relatively low a very small servo will be used since they are inexpensive, easy to control, and small. The hole for the servo horn was copied from the 3D Printed Automatic Tea Maker project.
Messy look at servo cam
Cleaned up servo cam

A second part was started which will hold the distance sensor. The footprint was made by referencing an online diagram which showed the dimensions in millimeters of the relevant parts. The parts are being made with the same approach as the previous projects where variables are declared in the beginning of the code and changing them will allow for the project to change as necessary without breaking anything. Another technique used more was the use of the use < > command which allows code written in other projects to be utilized without having to import bulky code.
Simple plane with distance sensor footprint
Screw wings added for enclosure assembly. Taken from Tea Maker project

To do:
  • Design method of holding the enclosure together neatly
  • Model enclosure
  • Design mount for servo which uses screws instead of bolts
  • Design way for servo cam to push on user without rubbing

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-17 (Tu)

Tuesday, March 24, 2015

2015-03-23 (M) 3D Printed Automatic Tea Maker INSTRUCTABLE

An Instructable was made for the 3D Printed Automatic Tea Maker. The Instructable was made by resourcing pictures from this blog. Only fifteen photos were selected for the Instructable and not all were used. This blog had dozens of photos which painstakingly showed the process from conception through revisions, mistakes, and finally the demonstration videos. The Instructable was meant as a concise guide for building the device rather than a journal which documented the building of it.

The project was entered into the Automation Contest and votes are always appreciated if you frequent Instructables. The project was featured very quickly and appeared on the Featured list of projects.

Screenshot of Instructable


Files for 3D Printed Automatic Tea Maker:

To do:
  • Make parts list
  • Make Instructable

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-23 (M)

Monday, March 23, 2015

2015-03-22 (Su) 3D Printed Automatic Tea Maker COMPLETED

The 3D Printed Automatic Tea Maker project came to a successful close. The enclosure was successfully printed after recalibrating the printer's table which caused two previous attempts to end with errors. The electronics were assembled in the enclosure with minimal issues. The screen did not fit exactly and had to be forced into place but only took a little effort. The bolts holding the screen in place were not exactly centered. None of these issues stopped assembly.

View of the inside after assembly

Close up of the inside

A USB charging cable was salvaged and the end was cut off to provide a USB end which could easily plug into a power supply or computer to provide power. The wire ends were soldered to the power terminals of the Arduino. Since the supplied power was now directly powering the servo motor some of the power issues noticed before went away. Once the unit was assembled it was tested and proven successful. Two videos were made to show the unit being run and the finishing of a successful run. #4-40 bolts were used to fill all the assembly holes.

Setting the tea maker and starting

The tea maker finishes brewing a cup of tea

GIF version of running the tea maker


Tea maker set up at my desk

Files for 3D Printed Automatic Tea Maker:


To do:
  • Print enclosure
  • Buy long #4-40 bolts and nuts
  • Assemble
  • Make parts list
  • Make Instructable

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-14 (Sa)

Sunday, March 22, 2015

2015-03-21 (Sa) 3D Printed Automatic Tea Maker

The code was revised to fix some issues and polish the operation. The screen LED now dims after three minutes. This was done by setting a long integer to the current timer plus three minutes, whenever that integer was reached the screen would dim over the course of approximately two and a half seconds. No inputs would be recognized during this time. The screen comes on immediately when an input is seen.

Before, the servo would bring the tea bag up as quickly as possible which created a situation where the submerged tea bag would splash or try to pull the mechanism into the cup. This was slowed down by moving in tiny increments and delaying between each one. The routine where the servo shakes off the tea bag was not changed.

The initial beep was shorted from 300mS to 200mS but repeated after the initial screen message of
Created by 24Eng
     Brian McEvoy
Using a double beep for start up seems appropriate.

The most updated code files were put into a Dropbox directory and made public. These copies were given concise names and will be update as appropriate so the most current versions will always be available through the link.




Possible Improvements for a second version:
  • Cover for servo motor
  • Tea string slides over a bar to dunk rather than lifting bag directly
    • Fishing rod style
    • Lift straight up
    • Easier to position
    • Servo arm length doesn't determine bag position
    • Uses a smaller cleat
  • Rounded end of platform piece
  • Spring-loaded posts for firmer mug holding
  • Screen says "Complete" after steeping
  • Dips tea slowly
  • Clip for stringless tea bags
  • Use discrete buttons and retentive memory registers
  • Use standard size Arduino and screen/button shield and retentive memory registers
  • Expand size of button hole
  • Expand size of potentiometer hole
  • Extend screen hole by 2mm in the vertical direction
  • Lower screen bolt holes by 1mm

Files for 3D Printed Automatic Tea Maker:

To do:
  • Debug code
    • Reduce jitter in timing 
    • Slow down tea lifting
    • Add time during shaking
    • Turn off LED when not in use 
  • Make code public
  • Print enclosure
  • Buy long #4-40 bolts and nuts
  • Assemble
  • Make list of possible improvements for a second version
  • Make parts list
  • Make Instructable

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-13 (F)

Saturday, March 21, 2015

2015-03-20 (F) Weekly Summary

This week was all about the 3D Printed Automatic Tea Maker. In fact, the project was close to wrapping up successfully.

There were three printable parts vital to making the tea maker. The base which holds everything to the mug (3 posts), the platform (t-shaped) which holds the servo, and the servo arm (key shape) which dips the tea bag. These designs were modified and corrected to work better. The base posts were rounded to look nicer and fit larger cups. The key was lengthened and the hub was expanded to fit a servo horn better. The platform was spaced to fit a servo.

Revised parts shown above their first version counterparts

The electronics for the project were soldered together. This step came later than usual but the input and output were not fully decided upon so it was prudent to wait. The equipment chosen for the project was intentional. The switch used was lower quality than preferred but extremely easy to find and cheap. In addition, the switch could be installed from inside the enclosure so it could be wired immediately for testing then installed without having to break the wires or solder again. Most of the components worked well immediately. The speaker was replaced with a more appropriately sized headphone speaker.

Most of the components soldered together
Start up screen

Once the soldering was done a good deal of programming was completed to get the project working. Some of the algorithms needed to be scrutinized drastically in order to display properly. The biggest and most vexing problem was receiving unexpected data when calling a particular function. The problem was the lack of a return statement which was similar to the HeartBleed bug. The bug in this program returned subsequent data registers rather than the desired integer.

Video demonstration

Fritzing was downloaded for an attempt to utilize the breadboarding display feature commonly seen around the internet. The first step was to create the schematic which was very intuitive and will likely be used in the future. No breadboard display was generated but the schematic was valuable.

 Schematic diagram

With the electronics and programming under control the enclosure was started. This was my first attempt at an electronics enclosure but being able to print an enclosure with an LCD cutout precisely included was valuable since the usual method was to cut a very ugly hole using knives or a Dremel. The measurements for the LCD were done by a combination of measurements and dimensional diagrams found online. The model was generated with OpenSCAD.

Measuring an LCD with a digital caliper

Animated view of the enclosure


Files for 3D Printed Automatic Tea Maker:

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

A list showing of all the final posts of COMPLETED projects.


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, March 20, 2015

2015-03-19 (Th) 3D Printed Automatic Tea Maker

The enclosure was modified to include a hole in the side of the top to allow a power cord to pass through. The hole was made by adding a circle and extending it with a cube so there would be no material hanging in free space. This will make it simple to insert a round wire.
Power hole


The program Fritzing was downloaded since it is commonly seen with Arduino projects for documenting the breadboard process. The software is free and open-source. The schematic layout for Fritzing was intuitive but lacked the library size found in Eagle CAD. Since the power will go directly to the Vcc and GND there will be no need to modify the servo connections since it will reside on the power terminals. A circuit board will not be produced for this project but one was generated by Fritzing to experiment with the feature.

 Schematic made in Fritzing

Circuit board made in Fritzing

To do:
  • Debug code
    • Reduce jitter in timing 
    • Slow down tea lifting
    • Add time during shaking
    • Turn off LED when not in use 
  • Hardware
    • Make power supply go to servo power
    • Add 5-6V power in
  • Make code public
  • Design enclosure
    • Power
  • Print enclosure
  • Draw schematic

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-12 (Th)

Thursday, March 19, 2015

2015-03-18 (W) 3D Printed Automatic Tea Maker

A text file was started which outlined the important measurements for the enclosure. Those measurements were added by referencing a dimension drawing found online by searching for "1602 LCD dimension." Once the appropriate variables were assigned some of the basic shapes were programmed without entering them in the OpenSCAD program. There was an advantage to this and a disadvantage. The advantage to programming with no error checking was that there was no temptation to check for errors so the workflow was uninterrupted. The disadvantage was that compounding mistakes, such as measurements which relied on previously entered measurements, were potentially huge.

Text file containing beginning of enclosure code


Once the code was put into OpenSCAD some of the mistakes were corrected such as the placement of mounting holes for the LCD screen. These holes were visually investigated and appeared consistent with the dimension drawing used as a reference. No port for power was modeled since the method hasn't been decided. A hole may be drilled in the existing version unless other changes are needed in which case it may be reprinted.
3D model of enclosure front and back

To do:
  • Debug code
    • Reduce jitter in timing
  • Hardware
    • Make power supply go to servo power
    • Add 5-6V power in
  • Make code public
  • Design enclosure 
    • Screen
    • Potentiometer
    • Power
    • Buttons
  • Print enclosure
  • Draw schematic

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-10 (Tu)

Wednesday, March 18, 2015

2015-03-17 (Tu) 3D Printed Automatic Tea Maker

A new set of the revised parts were printed. These revised models corrected the known problems with the first set including a base which wouldn't fit some larger mugs, a platform which didn't fit a servo motor and a key which was not long enough and didn't fit a servo horn well. A bolt hole in the base piece did not line up so it was remodeled and printed after the error was noticed in the print.

 3D models in the printing software

Corrected base piece in the printing software

 Printed parts

 First versions on top, revised on bottom, faulty base in lower left

The 16 x 2 text display showed the correct start up sequence but quickly became nonsense when the program was running. The initial display was encouraging since it demonstrated that text could be properly displayed and the problem was not a wiring issue. To diagnose the problem some lines and functions were removed until the problem disappeared but the majority of the code was disabled. The problem was elusive but tracked down to a function which was supposed to return a text string but returned nothing so the program spewed all its data. This was the problem with the HEARTBLEED security hole.

 Properly displayed text

Nonsense on the screen

The servo motor functioned well without any need for code modifications. The angles had to be adjusted so nothing would collide. The unit was assembled when the angles looked good. All the 3D printed parts were put together and fit well. Hardware store bolts in 4mm and 5mm were attached with nuts purchased at the same time.

Videos were made to demonstrate the tea selection potentiometer and the function of the tea maker. The times displayed in the video where the tea maker lowers the servo for a few seconds were modified for the video to demonstrate proper timing rather than accurate tea steeping times.

Selecting a steep time and seeing the corresponding tea names

Demonstrating the tea maker with a shortened time

To do:
  • Solder
    • Repair
    • Attach selector pot
    • Correct potentiometer
    • Replace speaker
  • Download and test code
  • Debug code
    • Reduce jitter in timing
  • Hardware
    • Make power supply go to servo power
    • Add 5-6V power in
  • Make code public
  • Design enclosure for screen, potentiometer, power, and buttons
  • Print enclosure
  • Draw schematic

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-09 (M)

Tuesday, March 17, 2015

2015-03-16 (M) 3D Printed Automatic Tea Maker

The circuit was soldered according to the I/O list from the program. The list was transcribed to an Evernote file and displayed on an iPad for easy viewing during the soldering process. The largest component was the LCD screen so soldering started with it. Scrap phone wire was harvested. Red and black wires were primarily used for power wires while green and yellow were used for signal wires. Colors were simply alternated to avoid overuse of a single color as opposed to assigning colors to a particular signal type. (An alternative could have been to use green for inputs and yellow for outputs as seen by the microprocessor.)

Backside of soldered LCD

The LCD was the most time consuming component to solder. After it a three terminal header pin was soldered to the Arduino to supply power, ground, and signal to a servo. Several methods were investigated for the terminal but the header pins will likely be glued in place once the enclosure is printed. A small switch was selected from stocked components. Other switches were available which looked nicer but the chosen switch is very common and has the advantage of being installed from behind the enclosure so it can be soldered immediately, troubleshot, and installed later without having to desolder it. A piezo speaker was taken from stocked components and installed to the Arduino on the buzzer pin. This speaker has not been used before so its output is unknown. Pin 13 was intentionally left unpopulated since this is the onboard LED which can be used for device feedback.

Soldered project

To do:
  • Solder circuit
    • LCD
    • Servo terminal
    • Switch (must be inserted from rear)
    • Piezo speaker
  • Reprint 3D models
  • Download and test code
  • Debug code
  • Make code public
  • Design enclosure for screen, potentiometer, power, and buttons
  • Print enclosure
  • Draw schematic
  • Make notes for special Arduino functions
  • Build breadboard circuit
  • Compile and test

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

A list showing of all the final posts of COMPLETED projects.


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.

2015-03-08 (Su)