Friday, April 15, 2016

3D printed battery holder

I was designing a project that was meant to be portable. For that I needed a portable power supply. The project was designed around an Attiny85 and some leds. So any voltage above 3.3 would do. I desided to use 3 AAA batteries (the smaller penlight types) which would bring enough juice.

There are many battery holders up for sale like the one below.

The problem with this is the shape. It is almost square so I needed a housing next to it for the electronics. That would make the deign needless complicated and unhandy. So when you call yourself a tinkerer that's what you need to do: tinker.

I opened my web browser and surfed to my favorite cad program: Tinkercad

In Tinkercad I designed a simple battery box.

So the next step was to print it and test it.

On the top sides of the box two small holes were drilled. Next I straightened a paperclip with a plier and bend it so I had a loop in it. The lopp was put inside the batterybox and acts as the contacts. The two ends of the paperclip were put through the drilled holes.

And here is the result.

The proof of the pudding.......

Ok, so it works. Next I designed a standard housing for 3 AAA batteries. That was easy. In Tinkercad I first made a copy of the above design. Then I pasted that 2 times into the design page and merged them. The result is this:

Printed that looks like this:

The picture shows how the paperclips were bended to create a kind of loop that would hold the battery firm in place and makes sure that there is a good contact with the poles.

The other side of the box has the paperclips connected in the same way so the batteries are put in series. I do need to add one thing though. I need to make marks for the + and - signs so you know how to put the batteries in. For now just look at the picture below where the design was tested.

So now the concept was fully working I could design the box for my project and it looks like this:

Neat isn't it. A nice box with a small enclosure in the middle to put the electronics in.

For those of you who need a battery holder I herebye give you the STL files which you can slice and print yourself.  I am sure that by using these you can design your own electronics enclosure box.

As I was doing a project with an ESP8266 I needed a more powerfull energy source. So I designed another battery box for AA battries. As a bonus I will add the STL file for a single AA battery case. I am sure you can combine it in your favorite CAD/CAM program to a case for multiple AA batteries. 

AAA battery case
3 AAA battery case
AA battery case

Till next time.
Have fun

Luc Volders

Friday, April 1, 2016

Oogoo and Oobleck

Strange names for some fantastic materials which are fun to play with and even are usefull.

Let me draw the situation for you. After more as 25 year my faithfull Nilfisk vacuum cleaner stopped working. So we needed a new one. And I bought a Karcher type WD3. It was on advise of a collegue of mine that I bought it. I was looking for something fancuy like a Dyson. Then he told me he knew me (and my girlfriend a bit) and the only thing that is of inporatance to us is functionality. So the Karcher is perfect. Enormous suction power and able to clean dry and wet spots. Yes indeed it can suck water !!! Ideal for us.

There is only a small problem. The Karcher is delivered bare. Luckily we had some accessories of the Nilfisk. Guess what ...... they did not fit. Naturally I started thinking about designing adapters which I could print. But there is a far more easier solution. A solution I had never tried.


The name Oogoo is derived from a product called Sugru. It is a flexible kind of plastic that is kind of moist and soft when you start working with it and can be molded in any form you like. After a while it will dry but stays flexible. Ideal for what I was planning.

Now Sugru I have never seen in Holland and is as far as I know now available for sale over here. I could order it over the internet but it is rather pricy. So I looked to the DIY version called Oogoo.

Oogoo is easily made you just need 2 ingredients.

The first ingredient is Silicone caulk. You need the clear one, the basic cheapest one. When you buy a tube make sure you smell at it. If you smell vinager you;ve got the right one. As you can see I used the Universal Silicone Caulk from Pattex. About 2 and a half aero from the diy-shop.
Make it easy for yourself and buy a caulking gun. It makes using the tube a lot easier.

The next ingredient is starch. Corn starch to be specific. For the Dutch people amongst you: we call it Maizena. Any type will do as long as it is pure. It is a frequently used product in the kitchen and can be found in any supermarket. Costs next to nothing.

And we will need some tools.

A mixing pot. Anything will do. I used a plastic cup. But you can also use an old saucepan or bowl. You will also need something to mix the ingredients with. I used a wooden stick but a spoon will do or a fork.

You definitely want to use gloves. The oogoo will stick to your hands and the silicone caulk is not the most healty material.

Start with putting Silicone Caulk in the mixing cup and add an equal amount of Cornstarch. Now just mix it up till you get some thick paste.

If you use more Silicone Caulk the paste will stay longer flexible and workable. Use more starch and you´re working span will be shorter. With a one on one mix you will have 10 to 15 minutes before it hardens.

After mixing you can mold it in any form you want. I made a reasonable amount so I had enough for a 15 cm long slice and some balls. Mold it with your hands. I tried to roll a glass bottle over it to make a real nice flat surface but that would not work as the paste woud stick to the bottle. So I molded it by hand. On some plastics and metal it will stick but can easily be peeled off when cured.

The slice was what I actually needed. I folded it around my vacuum cleaner tube and one of the accessories and voila an adapter was made. Just fold it around the two items and let it dry for about an hour or so. It will remail a great flexibility however fits tight around the tube so no false air will be sucked in.

And here is the end result. Works like a charm.

The balls are just fun. They really are bouncing balls. The elasticity of this product is amazing. However be carefull with this as they will bounce all through your house and most likely break something..... Still they are great fun to play with. Let the child in you come out !!!

Oogoo is cheap and fun and easy to work with. I am sure you can find many purposes for this. Just search the internet for Oogoo or Sugru and you will be submerged in applications for it.

I made some for my girlfriend who uses it as a foundation for some of her miniature-artworks. She has a new project: painting on crown-caps. And the caps just easily press into the Oogoo.


All work and no play makes a dull day.

So while I was working with cornstarch anyway I decided to make some Oobleck.

Now Oobleck is something useless but fun to play with.

First let me show you how to make it. It's really easy.

Put some cornstarch in a bowl and just add water to it. Mix it by hand till its a milky-white substance.

Some time during the mixing you will find that the stuff is hetting hard where your fingers scrape over it. Then you're done.

Now firmly scrape in the bowl and get some of the hard stuff out with your hand.
Spread your hand and see it get fluid again !!!!

This is a really strange experience. It gets hard when you press it and as soon as you release it it will get fluid again.

This is scientifically called a non-newtonian substance.

So surprise your friends or girlfriend.
Put a bowl of Oobleck on the table. Now hit hard with your hand or fist in the bowl. Everyone expects the fluid to splash around the table, on the floor and on them etc. But that's not what is going to happen. The Oobleck hardens as soon as you hit it with great force and becomes solid !!!!
As soon as you release your hand it will get fluid again. Amazing !!!

I put a bunch of it in a plastic bag and pressed the air out before closing it. This way you can keep it for many days.

The movie shows you that it acts as a fluid in the bag, but when you tap on it, it will be rock hard. Just search Youtube for Oobleck and you will find tons of movies of people having fun with it.

If you let it sit in a bowl for several hours/days without touching it the Oobleck will form a very hard solid mass. Now if you swirl it in the bowl like it was a fluid, it will indeed become a fluid again.....

And for some real fun. Look at the video where people actually show how to walk on 8000 litre Oobleck. Be amazed.

A really magical substantion worth playing with !!!!

So till next time.
Have fun

Luc Volders