Category: misc

Hat cam v2


I am having some amazing progress with my hat cam. I am so far ahead that I actually dare to call it Hat Cam v2 🙂

The idea is that instead of my wife’s compact camera I will use my new company mobile. The compact camera is a Fuji F480, that can record video in 320×240 resolution. That would be fair enough for documenting, but some serious limitations made it less than adequate.

– it could not zoom during recording

– it could not meter light during recording (and adjust light levels)

– it crashed if the light level exceeded a limit during recording (and the recording was lost as well)

– it had limited dynamic range indoors, almost none at dusk/dawn

The mobile phone is a modern smartphone from Samsung that can record in FullHD (1920×1080) if needed. From my side it is not needed, I set it up for 720×480 resolution. Plenty enough for me. What it can do besides:

– it has amazing dynamic range, great recording during any time of day

– it has a reasonable wide-angle lens, good for hat cam

– it can adjust metering during recording

– it can tolerate light level change without crashing

– it can zoom during recording (although no optical zoom, just digital zoom)

– it is very light, some 116 grams (I have to add weight of my bracket)

The big miss is that the mobile phone does not have a tripod mount threaded socket. This is something that mobile phone makers could consider maybe 🙂

Anyhow, I thought that I just make a tripod mount bracket for this phone. A world premiere maybe. Or maybe not.

Please see my build pictures. I used 2 mm plywood, some epoxy for gluing. And for stiffening up the bracket some BBQ matches. Like a frame structure almost. Since I drilled a hole in the center I had to add an extra stiffening beam, that is the remaining plywood from the Easystar build (when I cut out the enhanced rudder). A true piece of engineering this is, very basic in deed, but functional.

This is how you should NOT have the nut. It has to be on the other side, so that the screw is pulling it onto the plywood and not ripping it off instead.

For having some soft interface between the phone and the bracket I added adhesive window insulation tape. This provides nice flexible support, the phone can just sit in the bracket without getting scratched.

I will need to test if epoxy can fix the 1/4″ nut stiff enough, maybe I will need to apply CA glue instead.

I will test this setup next time I fly. Please feel free to copy my design if you like it. However please do make precautions to not drop your phone if you do so. Specially if you have some heavier phone that puts more stress on the glue.

I almost dropped my phone, made some trial recording and the glue snapped. Now I have the nut on the inside, so that the clamping force of the threaded connection is pulling it onto the hat. This way I have better chances to not drop it. And the friction between the bracket and the hat will help to secure bearing of the camera.

The finished product:

Best regards,

Sir Crash a Lot


I just received my parallel charging board from Hobbycity. They were super fast, I expected the package for the end of this week, it arrived on Monday. Great service!

According to reviews it can happen that polarity is wrong on the connectors. This causes risk of permanent failure on the batteries that you connect to it. So it is a good idea to check connections and polarities prior to using this board.

Mine looks like following after removing the isolation from the back.

From behind

And from above:

From above

I think that this looks okay. The red wire is connected to the plus side of the main XT60 connector. And all the charging XT60 connectors are on the same side, the side to which the red wire is soldered.

I checked if the balancing port ground wire is connected to the matching side of the balancing connectors. It looks like so.

I just double check this one more time and then will do a big charging of 6 batteries at once. Since I received my 3 new Zippy 3S 2200 mAh 20C batteries I can use 6 packs. I just made sure that they are all okay, checked the voltages.

One came with 2.2V on one cell, this I corrected to 3.8V with the storage charge option on the iCharger unit.

Later I will try to make a short resume of how you can do such a parallel charge and what do you need to look at to be on the safe side. I will update this very post to give you more details. Stay tuned.

Best regards,

Sir Crash a Lot



My charger arrived


I was in a dilemma about chargers and PSU’s for some time, could not really decide. Now I made decision and ordered them.

I went for the iCharger 106B+ charger and a Lindinger 20A power supply unit.

I went for the iCharger since it is the best and this small model has just right performance for my needs. I plan to charge my batteries to storage charge on the long run and have a full charge prior to flying. This enables long life for them.

The 20A PSU seems to be too large for the 10A charger but the more power you have in the PSU the more stable voltage it can deliver during load condition. And the less it will use the fan for cooling itself. This seemed to be a good compromise in cost and performance.

I had my first charge recorded to show some interesting details.

The charger is quite heavy, you can feel that there is material in it. Good quality feel on the house, the connectors and the buttons. I have some plastic screen protection on the display, haven’t removed it yet. Like on mobile phones, you remove this on first use. This is no quality issue, I thought I might have it on for a while.

The PSU is cooled by a fan, the fan runs very smooth and quiet. I charged one battery so far at a time, we will see how it will run on more load. I plan to parallel charge several batteries at once.

The charger enables all sort of protection features. You can have time based protection, capacity based boundary condition. You can have temperature sensor readings and stop charging on some defined value. And you have the intelligent control of charge that checks all cells during the process.

When I charged the interior temperature of the charger went up to 41 degrees centigrade, this is not much I think. The fan ran quite seldom, noise level was not disturbing in a quiet living room. My wife was reading on the couch, no comments on her side.

What is annoying is the beeping, that you can disable. On default it beeps on every press of a button. That was commented on the side of my wife, she welcomes that muted beeps 🙂

I even did a storage charge, please see noise levels at that operation in following clip.

What next?

I will read the manual, that never hurts. And I will use parallel charge soon. Ordered a charging board from Hobbycity along with 3 extra batteries.

What I read is that you should check polarity on this board. Some of them are wrong polarity, you can damage your battery if you have a wrong polarity connection. I will check mine when it arrives.

I have 10A limit on the charger, this means that I can charge all 6 batteries together with 1.66A each. This is 0,75C charging, so it will take approximately 1.3 hours to charge all of them at once. Since I don’t discharge them fully I assume that maybe less time will be enough even.

With a 20A charger this would be even less time. But I am not in a hurry. Compared to the charger I used so far this is magic speed. The other charger took 6.5 hours per battery. That is slow.

I even have a battery monitor being shipped.

This small unit can display the voltage in all cells, you can check the status on the field. Can have it in the shirt pocket, a must-have almost. Costs 1.86 USD, that is almost like a box of milk that I drink every day. 3% and 1.5 liters costs approximately 12 SEK.

I can recommend:

– the charger,

– the PSU

– the milk even 🙂

Excellent news. My cell checker arrived even.



Best regards,

Sir Crash a Lot

An RC bus


I am attracted to heavy vehicles in general, worked with them also along my so-called career. I change company and my colleagues were kind enough to give me a radio controlled present that has close reference to buses. It is a bus actually. A radio controlled bus. Can you have anything better than that? 🙂

The bus is powered by an AAA-size battery. You can use rechargeable ones if you have such. The transmitter is powered by 2 pieces of such batteries. Signal is transferred by IR (infra) light. Since you will not use this model from great distances it is no problem.

There is a highlight that I need to talk about: you can switch on headlights. What a detail!

Please see a quick recording of the device:

I am not fully experienced with the controls but will practice more.

Update 2011-05-14, a bit more control. And offline FPV with on-board recording from the bus!

Thank you for the nice time, I wish you all the best!

Best regards,

Sir Crash a Lot

What is needed for RC modelling?


Maybe it is good idea to tell what is needed for RC modelling. This is what I learned, it might be subjective and linked to my scenario. But could be a good base for rethinking.

I would definately say that you need time and money in first place. You need to have also some room for this hobby. Even if you plan to fly your model outdoors you will need to do maintenance every now and then. So “renting out” the kitchen table could be an idea. Patience is a virtue here, you will need to get to some agreement with your partner.

Tools are also needed. I picked up this hobby with very low set of tools. I bought them as I progressed and sometimes I felt limited by the available set of tools.

If you start with a RTF model kit, so it is ready to fly from the box you will only need basic tools. But if you intend to maintain, do some sort of electric work on it (change motor, servo, etc.) you will need more tools. For an RTF kit you only need some small screwdrivers and plyers.

If you intend to get further you should consider more tools.

You might even want to measure small items.

If you want to take a deep plunge in RC modelling you get into electronics sooner or later. In this case soldering equipment could be a good idea.

My favourite item is the “3rd hand” tool. It does exactly what the name implies, it shall give you a much needed third hand when you need to hold the soldering iron in one hand, the soldering wire in the other hand and the object that you intend to solder just get tossed around on the table. Before your blood pressure might get into the critical range it is good idea to use this tool.

Soldering means more tools. I started with a basic 30W soldering iron. It is very basic. You plug it in and off you go. However there are flaws to it. The tip does not warm in an even way, I cannot change the effect and working with it is very cumbersome.

So I bought a stand for it. Hoped that it helps. It solved the issue of “parking” it while being hot but the uneven warming remained.

I think the best would be to just buy a proper soldering station that can have better effect control and better overall quality.

If you are getting deeper in electronics you might use a multimeter. It can track lost connections and help a lot if you know how to use it. I don’t own a multimeter yet but plan to get one.

Of course as you get specialized to some model you might need special equipment. Helicopters need for instance a pitch-gauge to set rotor pitch. But nothing is impossible, you can survive without one in the beginning.

With some imagination and the power of Google you can substitute a lot of special tools with more simple solutions.

I was not really good at using tools earlier (still having problems), with time I can see some improvement. Practice does the trick. If you use tools while working with your hobby you get the hang of it without noticing. I don’t tell that I became Black-Belt in soldering, I would say that I am still walking on thin ice when soldering. But improving slowly 🙂

When you use tools always think twice and act after. Prepare the table for instance. Do you work with sharp items? Have something underneath so you don’t damage the kitchen table. Are you not so used to sharp tools yet? Have some first aid kit prepared. Do you start with soldering? Have clearance from flammable items, take good caution with soldering iron. It is important to enjoy the hobby but injuries and damage can be a avoided with some care. Be safe with tools.

I think that as a base package this would be enough. As you get specialized in RC modelling you will create your own toolset based on experience and personal preference. My intention is to give a base for those who just begin with RC modelling. Hope that I can help.

Best regards,

Sir Crash a Lot