CR4® - The Engineer's Place for News and Discussion®



Workbench Creations

Workbench Creations is the place for conversation and discussion about do-it-yourself (DIY) projects. This DIY blog will feature projects completed by its owner as well as projects completed by other do-it-yourselfers. Workbench Creations is the place where DIYers can discuss ideas, learn about what others have done, and share their expertise.

Garden Shed

Posted October 21, 2017 11:02 AM by phoenix911
Pathfinder Tags: Garden Shed

Good day fellow members.

I had posed a question last February about soil and foundations;

Floating Slab or Footings Below Frost Line

I appreciate your responses, concerns and suggestions from that thread.

Just to bring you up to date on my recent project, which was a garden shed.

I had just completed the project, I did do quite a bit of documentation and I like to share it here with you. The documentation was quite extensive, it is on another site. I'll copy the link here.

It was interesting and quite enjoyable project. And even more enjoyable now that's it's complete.

where it started with a sketch.

and ended with

13 comments; last comment on 10/31/2017
View/add comments

Del's Quiz Question!

Posted January 11, 2017 1:18 PM by Del the cat

You obviously couldn't make an arrow out of 2 layers of printer paper, it would buckle as it tried to flex round the bow.
What would happen if you made a paper crossbow bolt to shoot from a 50 pound draw weight 6" draw bow pistol? Give it a 50 grain point and a short wooden stub at the back end for string contact. Will it buckle or collapse?
The bolt is made as a tube, 2 layers of paper thick rolled into a tube 5/16" diameter same as a regular arrow.
If you want to see the result click the link:-
Del

15 comments; last comment on 01/12/2017
View/add comments

MkII Archer Automaton

Posted December 28, 2016 8:03 AM by Del the cat

Over the last few weeks I've rebult the Archer automaton with several improvements. Although there are only two basic movements driven by cams the interaction of the parts is surprisingly complex. It took an awful lot of fiddling and trial and error to get it working reliably.
Easy enough to get it working once, but I had to take a lot of slop out of the system to make it reliable.

Here's the video:-
https://youtu.be/UajIxPdUZVE

One of the key elements was turning a tiny cone of antler on my little lathe, this is fitted onto the string and allows the archer's finger to slip over it in one direction and to snag onto it as it draws back.

The control rods that run up the back were originally of ply, then copper sheet and eventually steel.
I decided to power it from a hand turned crack and wooden gears which were made from this site's free gear drawing program (the old version of the program worked better for me).
Del

19 comments; last comment on 01/07/2017
View/add comments

Archer Automaton

Posted December 07, 2016 4:29 AM by Del the cat

For ages I've been tinkering with the idea of making an archer automaton. There are some superb Japanese ones, but while they are incredible pieces of craftsmanship, the actual drawing action of the bow is all wrong.

I've just made a very simple prototype to prove my ideas... it's already being improved.
This very brief video shows it working.
https://www.youtube.com/watch?v=udnK4SXUtBY

Enjoy!
Del

24 comments; last comment on 02/01/2017
View/add comments

Backlight Fix on Vizio E420 LCD TV

Posted September 08, 2016 3:00 PM by HUSH

There are many, many things I’m saving my money for. Vacation. A wedding. A house. A boat? So a few weeks ago when my living room television began to malfunction, I was quite unhappy about the prospect of spending $400 on a replacement TV.

The TV, a 42-inch Vizio E420i-A0, was purchased a little less than three years ago. It worked reliably until one evening a few weeks ago, after a long day of work, errands and exercise, the middle horizontal 1/3 of the screen appeared faded. The top 1/3 and bottom 1/3 of the screen were as bright as ever, yet the middle was noticeably dimmer. This made watching dark scenes in movies and shows near-impossible (especially if you’ve just convinced your fiancée it’s time for her to binge watch Mad Men).

It seemed evident that it was a backlighting problem after some internet searching and reviewing a TV assembly diagram. Unfortunately there wasn’t much advice for my specific model.

Thanks to CR4, I’ve made some inroads with an electronics expert and DIYer, frankd20, a.k.a. Mr. Bad Capacitors Make Me Smile himself. With a strong electronics background, he’s rescued several TVs from the recycling heap. After quizzing him about how complicated a repair would be, he suggested getting some blog fodder for CR4 out of it as well.

We met up and set about removing the dozen or so screws holding the rear plastic housing that covers the power supply board, which receives power, and the main board, which receives input signals. frankd20 recommended checking out the power supply for loose connections, as power supply problems can manifest in so many different ways. We were quickly able to eliminate the power supply as the culprit for the malfunction.

Since it seemed like a panel or backlight problem, we needed to separate the back panel from the LCD panel, diffuser and prism films assembly. After a few screws and a few hidden clips, we were left with the metal back panel of the TV, with the boards located on its reverse. In the concave side of the assembly, we have five rows of ten ribbon LEDs, and a white background material to help reflect the light forward toward the LCD.

Unclipping the white background required us to remove the boards, which were added back so we could troubleshoot. Plugging in the power supply revealed that of the five rows of LEDs, only two—the top and bottom—were illuminating. The three rows running center were all out as they were connected in series. Looking at the LED layout online, I had guessed maybe that only the middle row was out, but had I investigated the wiring pattern better, I could have expected a larger outage.

Each individual LED required three volts, so a row of 10 LEDs required 30 volts. However, each row was made of two LED ribbons of five LEDs each. This actually worked to our favor, as all we had on hand was a spare 12 V power supply to test with. I shorted the left LED strips at the connection with a quarter while frankd20 applied power to the terminals. One by one, all LED strips illuminated, except for the last one. The bulb closest to the terminal had failed open, which caused the other four LEDs on the strip, and the other 25 LEDs wired to it, to not light up as well.

This was an opportunity for a part search, specifically LC420DUG-JFR1 LED strips. They are made in five and six LED strips. The ones I required, the five LED type, were out of stock everywhere I looked and also started at $50 for a whole set of 10.

It’s probably for the best anyway—shipping would have taken at least several days, and frankd20 came up with a solution the allowed me to bring the TV back home that day, not a week or more later.

After removing the malfunctioning strip, frankd20 scratched away the insulation between the broken LED and the subsequent LED. A little solder between the two conduits completed the connection, and when inserted back into the LED array, 49 of 50 LED bulbs turned on.

After some minor reassembly, I brought the TV back home where the fiancée was able to resume Mad Men, and I felt as though I saved myself a considerable sum with a little elbow grease and asking for help. Admittedly, frankd20 asked how far I would have got without his help—I reckon I would have gotten to LEDs, but I probably would still be searching for replacement strips. So frankd20, if you’re reading this, thanks!

One more note: two weeks later I reopened the TV, because when we put the LED strips back in, we probably didn’t push down hard enough for the adhesive to transfer the heat from the strips to metal backing. At least I had better confidence on that occasion.

5 comments; last comment on 09/12/2016
View/add comments


Previous in Blog: 3D Printing a NASA Space Wrench - Video  
Show all Blog Entries in this Blog

Advertisement