Giant compass

I made this compass today.

It's a big one.

It's quite simple. 2 pieces of wood. Drill a hole in one leg to hold a pencil.

Make a hole in the other leg, saw the top off a screw and screw it in the hole head first.

The legs are held together by 2 thin pieces of scrap wood.

Fix those really well on one leg and use a butterfly screw to hold the other leg.

It's not exactly rocket science but it's better than using a string or something like that.

Test circuit

I have put together a test board of my power supply and it works pretty good. I may do a bit of fine-tuning so I'm not posting the circuit yet but it is something like this with a few modifications. The heat sink this guy uses seems way too small unless he's using a separate circuit to detect overheating but he doesn't speak about that...

Based around the good old 723 voltage regulator.

The multi meter is also finally paying off :-)

Another close up. Breadboard fun...

First table design

I'm looking for a place where I can see and enjoy my model trains but I don't want it to take up part of or a whole room. I want it to be a static display but also dynamic. It has to be technically challenging in lots of different ways. It should be fun and functional and also it should look good because my girlfriend is not into model trains so it may not be in her way ;-)

So I'm going to make a coffee table model railroad.

I tried this before but it was a shonky quick and dirty job so now we're going to prepare better starting with designing the track layout and now the table itself.

This is the first attempt in designing the table. It will also get a glass top. The cylinders will hold the rail coil on the outside and the inside will not be covered by glass, leaving an opening for i.e. a plant. It has yet to be decided what kind of "feet" the table will get...

The design tool used by the way, is Sketchup from Google.

Power supply (1.5-30V / 2A), part 1.

To be able to do some electronic hobby projects you need a power supply. You also need other things like a multi-meter for example but that's harder to make. Power supplies are much easier to make and often a lot cheaper than one from the shop.

So I'm going to build a 1.5-30V/2A power supply which is sufficient for most little projects.

To start you always need to convert your mains power (110 or 220-240V) to something more suitable like in this case 24V. Because I didn't want to have all those high voltage parts lying around while working and testing the circuit I decided to make the case first and put all the high voltage stuff in there.

Here are some pictures:

That big chunk of metal is the transformer. It turns 220V into 24V. It's screwed on to the bottom of the casing. It's 72VA (which is 72W coz voltage (V) x Current (A) = Power (W)).

The back and the front panels. The back panel holds the socket for the mains cable and the fuse. ALWAYS use a fuse! For this project I use a 500mA fuse. This only protects the house from a power outage. To protect my equipment I should actually use a fuse of (72/220) 0.3A. I have to see if those actually exist...

The front panel holds the switch (which I'm not happy with because I thought it would be pretty blue but it's stupid blue light) and 2 connectors for the output voltage of 24V.

A close-up of the front panel, just because it's a cool photo ;-)

This is the front after putting it together...

... and this is the back.

I forgot to take a photo from the inside with all the wires attached. That might have to come in Part 2.

With this part finished, I now have 24V at my disposal in a safe way!