Wednesday, December 7, 2016

2016-12-06 (Tu) Clockwork Theremin

A new H-bridge arrived and was connected. This model was only built to control one motor but it could easily handle the current. It was rated at 43 amps so the peak current, less than 20 amps, shouldn’t provide any problems.

New H-bridge connected

As soon as it was connected properly, which took longer than it should have, it was clear this motor controller was different from the previous model. When 40% duty cycle was applied the motor spun aggressively instead of just beating inertia. The starting duty cycle was lowered and a mere 8% was enough to move the motor. 8% was approximately one volt. Hopefully, this meant that the initial speed was only 1/12 of the final speed capable with this motor.

Meter connected to read motor voltage

An animation was made of the gears moving. This animation was actually a ping-pong loop. The actual recording was the gears moving in one direction but the animation reverses the frames to give a smooth animation. The gears were extremely loud and the motor made a high-pitch sound, probably the PWM frequency.

Gear animation

The high speed movement of the gears caused the left-handed nut on the motor shaft to loosen more than once. A nut driver was kept nearby to reattach it as necessary. It will be important to use a chemical thread locker or at least a mechanical lock washer.

Nut driver to retighten nut

Downloads:
Parts list:

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.

Completed projects from year 3.


Disclaimer for http://24hourengineer.blogspot.com/

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 property or assets based on their post.

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

2016-12-06 (Tu)

Tuesday, December 6, 2016

2016-12-05 (M) Clockwork Theremin

A list of four questions was written before any more testing on the motor was done.
  • What is the minimum duty cycle to turn the motor?
  • Will an initial jolt of full power make the motor turn at low duty cycles?
  • What is the effect on the motor when full power is applied?
  • Does the motor need a small jolt to make the teeth mesh?

The slow ramping program was given a serial command so it would constantly display the speed. To test, the speed was slowly increased and when the motion was detected the current duty cycle was recorded. On the first attempts, the duty cycle reached 90% before there was any motion. The H-Bridge was exchanged for one that hadn’t released any smoke. Then the same program reported that only 35% duty cycle was necessary to move the motor. For this reason, the H-bridge was scrapped.

Yes, that's a pink phone holder

Despite a fully-functional H-bridge in the project it still ran hot. The heat sink became hot to the touch after a few seconds of running. To demonstrate, an infrared thermometer was pointed at the heat sink while some basic motion was demonstrated. The program had been changed to never use less than 35% duty cycle so the motor is very responsive to the buttons going forward and reverse.

Narrated video of H-bridge demonstration

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

First time here?


Completed projects from year 1.

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Completed projects from year 3.


Disclaimer for http://24hourengineer.blogspot.com/

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 property or assets based on their post.

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

2016-12-05 (M)

Monday, December 5, 2016

2016-12-04 (Su) Clockwork Theremin

Yesterday's Arduino sketch was uploaded to a generic UNO board which was on hand. Since the program was so simple it would be no trouble to upload the same sketch to any board with enough pins. If PWM wasn’t capable on the output pins it would be a simple matter to rearrange them to match any board from a Pro Mini to a MEGA. A simple circuit was connected on a breadboard with a couple buttons and a couple LEDs.

Components and battery

For the purpose of a demonstration, LEDs were connected to the outputs. These simply demonstrated that the outputs were using an increasing duty cycle. This was narrated in the video as well. Each button outputs to the LED next to it, one red and one green.

Video demonstration of ramping program

A second video was taken and narrated. This video demonstrated the change in duty cycle on a digital multi-meter. The readings gradually increase and the bar graph at the bottom of the screen increase proportionally too.

Program demonstration with meter

Experimenting with the program lead to some discoveries about the motor and H-bridge interaction. When a low duty cycle was applied there was no movement but the motor would make a high-pitched tone that increased in volume as the duty cycle increased. When enough power was delivered the tone would stop and the motor would turn silently. Presumably, this tone was a product of the PWM. Since moving the motor was more than a simple matter of applying a duty cycle from 0 to 100 percent, more experiments will have to be run with the Arduino sketch. Several questions will have to be asked and answered so that an effective program can be written to control the gear boards.

Downloads:
Parts list:

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

First time here?


Completed projects from year 1.

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Completed projects from year 3.


Disclaimer for http://24hourengineer.blogspot.com/

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 property or assets based on their post.

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

2016-12-04 (Su)

Sunday, December 4, 2016

2016-12-03 (Sa) Clockwork Theremin

High power through the jump starting battery was nice but the connection was troublesome and unfused. An inexpensive power cord for a car's cigarette lighter was purchased at a surplus store. This had a 15 amp fuse installed which was quickly tripped when I hooked up the wires incorrectly to an H-bridge. Some smoke came off one of the components and the fuse was replaced.

 Cigarette lighter plug and a blown fuse

 When the H-bridge and power cord were connected properly, a meter was connected to show that voltage was indeed going to the correct pins. The functionality of the H-bridge was not tested since it could lead to run-away speed on the motor.

Ensuring the H-bridge and battery were connected properly

A simple sketch was written for Arduino. This would rely on two buttons to slowly ramp up the speed on the motor in forward or reverse. All power would be cut when the button was released. There was no need to debounce the buttons.

Screenshot of Arduino sketch

Downloads:
Parts list:

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.

Completed projects from year 3.


Disclaimer for http://24hourengineer.blogspot.com/

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 property or assets based on their post.

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

2016-12-02 (F)

Saturday, December 3, 2016

2016-12-02 (F) 2 Cyborgs and a Microphone EPISODE 014


Episode fourteen has been edited and released. I would argue that our "Why" episode was our best to date but this episode had a lot of glib conversation and it was more relaxed than most. When we started the podcast I knew it would be rough and we would sound wooden but I was also confident we would improve and this is a testament to that improvement.

Fourteen episodes is a short amount of time to get accustomed to this although that represents a lot of recording time and much more than gets into the show.

I'm the cyborg with the bionic right ear


Ad spot for 2 Cyborgs and a Microphone

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.
Completed projects from year 3.



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 property or assets based on their post.

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


2016-10-02 (Su)

Friday, December 2, 2016

2016-12-01 (Th) 2 Cyborgs and a Microphone


Our fourteenth episode was recorded and it was also the third episode recorded with an inexpensive Windows tablet rather than a desktop Mac. The sound quality shouldn't have changed since it was still using the same microphone and USB adapter. Since there haven't been any problems with the recordings it is now feasible to make a portable sound recording setup.

Egg crate foam has been salvaged from packing material at work so it may be possible to build an inexpensive shield for a microphone and stand. This wouldn't provide enough dampening to record outdoors but it may be enough to record in a quiet room. Carpet samples also provide significant dampening.

I'm the cyborg with the bionic right ear


Ad spot for 2 Cyborgs and a Microphone

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.
Completed projects from year 3.



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 property or assets based on their post.

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


2016-09-29 (Th)

Thursday, December 1, 2016

2016-11-30 (W) Clockwork Theremin

And ordinary extension cord was purchased and cut apart for the two-conductor molded cord which gives them their namesake. Both ends were removed and a small section of a single wire was also cut away for use inside the handy box. The short length was stripped and a small ring terminal was put on one side while the other was soldered to one side of the connector. This wire was installed between the connector and switch. The ring terminals made it easy to connect to the switch which happened to have short bolts. The motor lead which used to run to the connector was placed on the switch so the switch could effectively interrupt current.

 Handy box with wired switch

The majority of the extension cord wire was left intact. For testing, one end will be left as bare leads but the connector for the motor side was installed. A wire was soldered to each terminal in the connector. Some connectors, more expensive than the ones I ordered, come with an insulator inside the connector so leads cannot contact the shell, which was made of metal. A bit of heat-shrink tubing was cut and put over the wires to do the same thing.

 Soldered connector with insulating tubing

All the wires in the handy box were neatly placed and it was sealed back up. Now, it should be much simpler to drive the motor with longer leads and a technique for soldering wires to the connectors and switches.

Constructed motor junction box

Downloads:
Parts list:

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.

Completed projects from year 3.


Disclaimer for http://24hourengineer.blogspot.com/

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 property or assets based on their post.

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

2016-11-30 (W)