DIY Coat Rack

This year for christmas I built a nice coat rack as a present for my sister. I thought I’d just share the idea. It’s actually really simple. All you need is

  • a wooden board
  • some nice-looking hooks
  • a decorative piece of fabric or a photo that is a little larger than the piece of wood
  • screws to mount the board on your wall

I chose to use a phot that I had taken myself some time ago in the woods and get some decorative hooks that matched the woods theme. Download [download_link link=””]my photo[/download_link] if you want to use it.


Simply wrap your wooden board in the piece of cloth or fabric or photo, add some hooks for coats and screw in some loops or lugs so the whole thing can be hung on the wall.

This is what mine came out looking like:

Dead Woofer in Opera Active PA Speaker

The other day I got my two Opera Live 210 active PA speakers out and I noticed that in one of them only the tweeter was working. Oh no! So I decided to take it apart since it is way too old to be eligible for warranty. I was really surprised how well designed they are! Everything is neat and clean and almost as if they are made to be taken apart. What I found though was’nt that cool: I measured resistance of the speaker coil in the woofer with my multimeter and got an incredibly low .6Ω. Well I guess that means that it is practically shortened, probably in an overload situation. That’s very strange since these speakers are active and have a built-in overload-protection-circuit. I guess it didn’t work so well. ;-( To see if the part of the active amplifier that drives this speaker still works I hooked up my multimeter to its outputs without the woofer being connected. Turning the volume up or down didn’t change the displayed 0V. My guess is that this means that the short in the woofer also killed the amp in the process. That’s really too bad, because I really liked these speakers. They are no longer manufactured.

One funny thing I also found is that some screws had come loose over the years. They are used to mount the OpAmps to a cooling brick. One of those three screws had vanished so I looked around inside the case and I found it: it was clinging to the speaker’s magnet!

Listen to the awful sound of only a tweeter. I recorded the speaker before taking it apart:

Vandal Spur Gear Protection

Because the Vandal’s spur gear always drags in the dirt when racing this awesome car it is subject to significant wear. To protect it a little bit from the sand I cut out a tiny piece of plastic that I glued to the bottom of the chassis frame with some CA and then covered it with duct tape. I hope it lasts longer this way.

plastic glued on w/CA
plastic glued on w/CA
added duct tape
added duct tape

Vandal: loose screws

After my first ride with the Vandal yesterday, the front wheels had lost power. I figured something must gone wrong with the front diff. So today I opened up the Vandal and discovered, the screw that holds the drive shaft to the gear box simply had come loose.

Vandal images for Taranis

I created two pics of the Quanum Vandal for use as a model symbol in the FrSky Taranis Transmitter. Feel free to download and use them yourself!

vandal1 vandal2

TX Modes and Flight Modes

When I started getting into the hobby and I looked around for transmitters I was really confused with “modes”! What are those modes? Well, it turns out there are two very different things called modes in the R/C hobby.

Transmitter Modes 1 to 4

The first thing to know is that there are different ways to lay out the actual control sticks on a transmitter to control different axis of a model. For people just starting out or getting into model aircrafts I would recommend a transmitter  in mode 2. This today is the most common way to lay out the controls.  Mode 2 transmitters have the throttle function of the model controlled by the left stick:

Mode 2 TX
A mode 2 transmitter (this one is a FrSky Taranis)



Flight Modes

Flight modes are usually used to help switch between settings in different phases of flight quickly.

flight mode
Here the TX is switched to stunt mode

This is accomplished by flicking a certain switch.



This is especially helpful for models that need different setups for starting up, regular flight, landing and so forth. With helis for example there is the special situation that the throttle stick not only controls the throttle but at the same time it controls the overall (or collective) pitch of the main rotor blades together. So if you start up the engine of a heli, you need the TX to slowly increase the throttle as you raise the stick. At the same time, the overall collective pitch needs to increase. At some point, usually at around “half stick”, the heli will have enough lift from the pitched blades and the right rpm speed of the motor that it will start to hover.

Once airborne and if you want to do aerobatics with the heli, you need the rpm of the engine to stay at full throttle constantly so you can control all maneuvers with the main rotor’s pitch. That is what a heli’s second flight mode helps to do: it changes the function of the throttle stick in a way that this stick sends out a “full throttle” command at all times, no matter its actual position. It does, however, continue to control the collective pitch of the main rotor blades. When the stick is centered, the blades are at zero pitch, meaning completely level, that is neither generating lift nor pushing the heli down. If pulled down, the throttle stick makes the pitch go negative, if pushed upwards, the collective pitch becomes positive, giving lift to the heli.

My Taranis

I recently sold all end every piece of Spektrum equipment I had and converted all my models to FrSky technology. I really think it’s the best there is! Taranis Homepage

But I still want a transmitter that works for my Blade mCP X, Nano CP X and 130 X helis, so I decided to build my own transmitter module to use in the Taranis’ TX module slot. Out of my old DX4e I extracted the HF module and soldered it into an empty Spektrum case. Now I have true DSMX in my Taranis. To do this I followed this comprehensive article by John Prikkel.


HD-P2 powered with LiPo

One of the big downsides of the Tascam HD-P2 audio field recorder ist that it runs on 8 AA batteries. They don’t even last a day and it’s not very fast to change them all out in the middle of a production day.

So I decided to make an adapter to connect my 3S 3000mAh LiPos to it. I simply cut up the cord of its AC wall adapter and soldered two XT60 connectors to the open ends. This way, the AC adapter can still be used, but the new short adapter cord is perfect to connect to the LiPos. To be able to detect low voltage in the LiPo cells I simply hooked up a small LiPo alarm to its balance plug.

This setup proved to be very useful and the 3000mAh battery lasts at least one and a half days!

I built a “Dizzy Bird”

Today, me and a friend met up to finally try and build one of the famous Dizzy Birds ourselves. The whole wing is entirely made of 3mm thick Depron foam board and has a wingspan of roughly 1000mm. They came out quite wonderful, too! My friend’s flew beautifully. He built the non-powered version and it only weighs about 150 grams.

I added a 2205 1350kV 100watts 3 cell engine spinning an 8×4 prop. It weighs 341g including the 1300mAh battery. For radio components I used a FrSky X4R receiver to use with my Taranis and hooked up the little telemetry wires with A2 going to the flight pack through the tiny voltage divider FBVS-01. The remaining SmartPort wires are connected to a standard female servo connector so I can hook up more telemetry sensors in the future, maybe a vario.

I was actually too afraid to let it fly yet. It began to dawn anyway, so I’m just gonna have to wait a while to maiden the thing…