Another Battery Powered LED Light Tree

I was in a store in Monterrey CA that sells these really nice 'light trees' last year and I thought that it would be fun to try and make one myself. The first one I made one from scratch, buying all the parts at a hobby store along with LED Christmas Lights, and I wrote about it HERE, (an exciting video of how I made it is HERE). Anyway I was asked to make another LED Light Tree because the first one that I made turned out really nice ;-) When I went to the hobby store again to buy the parts I noticed that they are now selling LED Branch Lights pre-made! This is great because the majority of the effort in making the first LED Branch Light was making the branch itself with all the LED Christmas lights added into it. Check out the above link to see how I did it (or watch the video). I didn't have to do that this time but there were some other interesting things that I discovered while making this one with the pre-made LED branch.

 

Homemade LED Branch Light Tree

 

Above is a picture of how this LED Light tree turned out. Looks nice doesn't it? Click on the READ MORE link below to see the parts list and how I built this as well as something interesting I noticed in the battery pack for the LED Branch Light.

  

Homemade Wood Clock Construction

Last week I wrote about a homemade wood clock that I was designing in Solidworks. If you are curious there is a link to that post HERE, there are details about how it is going to work. If you don't want to read that post, the homemade wood clock design is as follows: I decided to make a clock that has an hour hand that stays upright, pointing straight up all the time and the face of the clock moves to tell the hour. Because the face is moving to meet the hour hand (instead of the other way around) the minute hand has to turn at a different ratio than in a 'normal' clock. To get that to work I designed a wood gear clock movement (gearbox) that has a 11:1 ratio with the face of the clock turning counterclockwise and the minute hand turning clockwise. Although I didn't make as much progress on this wood clock project as I wanted, I did manage to get some work done. I got all the gears done, the 'spindle bearing' figured out and the support structure made. Be sure to have a look at that last post I linked to above to see what I am trying to do.

 

Wood, Gears, Glue and Tools for the Clock

There are a few things that I got worked out in the design since last week and a couple of problems solved. One issue: I have never cut gears from wood before so this was a bit of a learning experience for me. To make the gear patterns I used an online Gear Template Generator from a site that I link to in the "Sites I Like" bar in the sidebar of my blog. Cutting the gear teeth started with printing out the gear pattern from the online generator above and gluing the template to Baltic Burch plywood. The Baltic Birch has a tight grain and the layers in the plywood are very thin making is good stable wood to work with. After getting the pattern on the wood I rough cut the gear out with a band saw then finished the teeth with a scroll saw and sanding. Getting the hole right in the middle of the gear was a challenge but I managed to do it. If anyone has any advice about making gears from wood I would like to hear it!

Homemade Wood Clock Design

Awhile ago I was looking at Roman numeral clocks and wondering why there is no standard way of putting the numbers on the face, specifically the number IV being 'upside down' on some clocks and not on others. I wrote about that HERE and since then have been thinking about making my own clock. Well now that I have had some time to think about it I have decided to go ahead and make a wood clock. This post is the first in what I expect to be several detailing how my wood clock design project goes. I have never built a wood clock and have never made gears from wood so this whole project is an experiment and learning experience for me (and my young son). Designing the clock movement and the gears from wood seems like a fun project!

   

Because of the Roman numeral clocks that I have seen with the IV sometimes upside down I thought that it would be neat if all the numbers were right side up. Having all the numbers right side up isn't too interesting but I also was thinking that the hour hand should always be pointing up too. After all the hour is probably the most important thing that you want to know first. So to have the hour hand always pointing up and all the numbers always right side up, would mean that the face of the clock would have to turn and all the numbers would as well. The minute hand of course would be rotating around but because the clock face is rotating too the ratio of the hand to the face would be different that a conventional clock. To get all this to work I decided to do a CAD model in SolidWorks of the clock movement (see 'click here to read more' link below) and do some research on making gears out of wood. While doing some web surfing research I ran across a really neat Woodworking for engineers site that I have linked to in the "sites I like" where I found a neat on line tool for generating gear templates. Below is a picture of a couple of the first gears that I made for my clock using the on line generator. they came out nice and seem to spin pretty well. It didn't take too long to cut them either roughing them out on a band saw and finishing the teeth with the jig saw. 

 

My First Attempt at Wood Gears for My Clock

I have designed several gear trains professionally but never for a clock and never from wood. As it turns out (no pun intended) getting the hands to move at the right speed and in the right direction is an interesting design problem. To figure all this out I did a CAD model in SolidWorks to make sure that the gear ratio was going to be correct, the minute hand and the face were turning at the right gear ratio and in the right direction. I also wanted to see how the whole thing was going to look at different hours of the day. Have a look below at the design and a short video that I made of the clock running.

Conditional Formatting in Excel and Prime Numbers

Numbers are cool and fun to play with in my opinion, especially Prime Numbers. I wrote about this some time ago in a post HERE and I've had some ideas since then. In that post I was using a Excel spread sheet with some Visual Basic code to create a number sequence then I was using another function to check if a number in a particular cell was prime. The function was scanning through a list of prime numbers in the spreadsheet and if it found a match the formatting for the cell that matches was changed to blue using Copy Formats in Excel 2007 instead of the Conditional Formatting idea. To do all that in Visual Basic for Excel was fun but overly complicated as pointed out to me by Codemann8. He commented on that last post and left a formula for Excel that can check to see if a number is prime! It's a cryptic and really cool formula that he didn't take credit for (it's out on the web) but it will check for prime numbers. I finally got around to trying this formula out and I used it to highlight prime numbers in a simple multiplication chart that uses modulo arithmetic. Below is what the Multiplication Modulo Chart looked like but I also want to show how to set this formula up to control Conditional Formatting in Excel 2007 because it took me awhile to get it to work.

   

Excel 2007 Conditional Formatting in Modulo Multiplication Table

   

The above picture shows what the spreadsheet ended up looking like. Along the top and down the left side are the numbers 1-257 (only 1-23 are shown) and in the middle are the products of those numbers - a multiplication chart. In the upper left corner in the highlighted cell is the modulus of multiplication. In other words the numbers in the top and left are being multiplied modulo 23 in this case. The blue cells are the prime numbers being highlighted by the formula below using the Conditional Formatting function. At the end of this post I made a short video that cycles the multiplication chart through various number sequences showing the various patterns the prime numbers make! Really Cool!!!

   

Below is the formula that Codemann8 left in a comment on another post I wrote and it checks to see if a number is prime returning the Excel TRUE condition if it is. If you 'Google' that formula you will get a bunch of pages that talk about it. Whoever came up with this formula had their thinking cap on!

=OR(A1=2,A1=3,ISNA(MATCH(TRUE,A1/ROW(INDIRECT("2:"&INT(SQRT(A1))))=INT(A1/ROW(INDIRECT("2:"&INT(SQRT(A1))))),0)))

Click below to read more about how to set up Conditional Formatting in Excel 2007 to use this formula and to see the boring exciting video I made of the spreadsheet cycling through various number sequences, highlighting the prime numbers as it goes!