Flyinglow

FPV! FTW! Finally!

Sat, 10 Jul 2010 16:31:05 -0600

Ok, so ever since I saw First Person Video's from R/C airplanes online, I have wanted to join the fun. The cost has been quite prohibitive however. The ultimate setups are real time virtual reality setups complete with on board telemetry and GPS navigation.

I've looked into mounting video camera's on the plane, however, the camera's available to date have either been too heavy, too expensive or poor quality video (or all of the above).

Well, a few weeks ago I was introduced to a keychain camera that records 640x480 for less than $20!!! It arrived on Monday and wow. It's small, light and the video is actually quite reasonable. Before ordering your own, check out this extensive research page. The unit I received is apparently a #7 version. Here's my camera (for those outside of Canada, that's a one dollar coin - about 2.5cm across):

and here's my first FPV video taken from my golden yellow foamy:

Enjoy! There will more to come I'm sure!!

Can I improve my air conditioner's efficiency?

Sat, 10 Jul 2010 15:35:03 -0600

Summer is finally here. Temperatures in Winnipeg are getting up to 30C and with that, the air conditioners are powering up. I've been tracking my A/C usage along with my furnace since January 2010. I'm actually surprised how little electricity the air conditioner uses compared to the electric furnace. In fact, to make the daily & monthly graphs 'interesting', I've had to multiple the calculated power usage by 10.

Now, 30C is not that hot compared to other places in the world, and in Manitoba our power is reliable, plentiful and inexpensive. After returning from a business trip to Southern Ontario during a very hot spell (highs of 35C) I began to appreciate how the air conditioners are able to strain the grid.

In a conversation back home the question came up - can an A/C unit be made more efficient by pouring water on the condenser coils outside? (We had been noticing water droplets coming off our office building during hot weather - and are assuming that the building is using water to cool the outside coils).

So, yesterday while the A/C was running at home I tried some experiments. The temperature was 27C outside, and because I have my thermostat cool the house down for night, the unit was going to run for a couple hours non-stop.

I measured the current draw on the compressor at 7.5A. This was my baseline. (And is what I have been using for my power usage graphs.)

Next I set up the garden hose and a hand held nozzle to direct a gentle mist or spray of water onto the condensing coils. I was thinking that a gentle mist would provide extra cooling by evaporating, and I also didn't want to create a flood beside my house from the water.

Back inside I took a few measurements of the current draw. I also timed how long 10 liters of water took to be sprayed onto the A/C unit. I wanted to compare any money saved by lower power with the extra cost of consuming water.

To my pleasant surprise, the current draw dropped by nearly 10%! After a few minutes of spraying water, the new reading was 6.85A (a drop of 0.65A).

10 liters of water was being used every 4 minutes and 12 seconds, or about 143 liters / hour.

Before pulling out the calculator, I did one last test. The coils outside pick up dust, seeds, etc and should be cleaned every year - I opened the nozzle up and gave the coils a good cleaning (600 liters / hour). The current dropped another 0.65A down to 6.2A!

Without a doubt, cooling the coils saves power. This is because the coolant condenses much easier when the coils are cooled down, the condensing lowers the pressure on the high side making the load on the compressor lower and hence the lower power consumption.

So, how much money do I save? Well, at $0.065 / kWh plus taxes, it works out to about $1.30 / month. Not much, but every dollar saved is one dollar earned, or something like that.

But while running water on the coils lowers power consumption and is good for the electrical grid, and lowers my power bill by a small amount - am I actually saving money?

Turns out, no. Water in Winnipeg costs $3.20 / 1000 liters. At 143 liters / hour, in one month (6 hours / day, 20 days / month), my water bill will increase by $54 - easily negating any electrical savings.

Anyway, for those who want to see the number crunching details, I've created a google spreadsheet where I ran the numbers.

Enjoy the summer!

History of flight - part 1 - Bitten by the bug

Sun, 25 Apr 2010 13:31:51 -0600

So back in pre-2005 back when I lived on a large (75'x330') lot in a small town, a friend gave me a couple old .049 control line airplanes. With a bit of cleaning and tuning, I was able to get them running.

The first plane to come to life was a balsa wood with 'STUN MAN 23' stenciled on the wings. This bird was almost manageable for a complete amature like myself. It required some major repairs to get airborne as the fuselage was broken in 2. The fix was to insert a couple small finishing nails into the balsa wood (like a surgeon would pin a broken bone) and press the two halves together again. To make the joint permanent I then wrap thin layers of surgical gauze and epoxy around the joint.

Being a solo pilot with little to no help / assistance, I had to devise a way to launch this plane. The normal procedure is to stand in the middle of the circle while a partner fuels, primes, warms up the glow plus and spins the prop over (many, many times - the 049's were not the easiest to start), trim the mixture to max RPMs, wait for the pilot to be ready and then release the plane.

I had no such assistant. So I rigged a remote release system. I tied 10 inches of string with a loop on the end to the tail gear. I tied another 10 inch piece of string with a small loop on the end to a tent peg which was driven into the ground behind the plane. I then tied a long string to a 3 inch nail. The nail was fed through both loops and then gently into the ground. The string was run the middle of the circle along with the control lines.

I would then go through the starting ritual, get the engine running full out which would pull the strings taught. I could not go to the middle of the circle get the control lines ready and with a firm tug of the 'launch' string the plane would be released and flying!

22 laps (less then 2 minutes) later I would be so dizzy the headache would last for days.

A second plane that was in the set was a P-40. This one was all plastic, with a newer motor that started somewhat easier, however, flying this bird was not easy and often ended badly. Plastic though it was, it was a good thing I actually had 2 as the second plane donated a few parts to keep the first flying.

The challenge was finding a plane sturdy enough to learn to fly the hard way. The P-40 was tougher, but harder to fly and so it still broke. The Stunt man was gentler for flying, but balsa wood is too fragile for beginners. Thanks to the Internet a solution was to be found.

TGIMBOEJ - "GRAY-E"

Mon, 12 Apr 2010 20:01:40 -0600

April 1st - 2010 - Gray-E arrived from @splorp in Calgary, AB. This box has made a number of stops (and is getting quite large).

Some notes:

I removed batteries - probably not a good idea to ship things that might leak nasties
I took the TI calculator because it is so cool - after removing the leaky batteries (see above) and inserting a 9V, I confirm it works! Wow. I like the cool retro red LEDs, but may not want to retrofit - it may be a bench calculator.
I took the WinTerm thin client - to replace my old PIII 500 workstation is very slow, takes up lots of precious workbench space (would take up less if it was gathered up into a case and not splayed out like a high school biology assignment gone bad).
I also grabbed the one-wire temperature sensors - these will augment my furnace monitoring project quite nicely.
I added a vintage CD-ROM to keep the Sony Walkman company
I added some heat shrink tubing 'cause I think it is useful (scavanged out of a Dell server no less)
I added some dual pole umpteen-many throw slide switches 'cause I have too many and have never used any
I added another small solar cell with wires attached (wrapped both the new one and the existing one together in tissue for protection)
I added the following HP LaserJet III parts

Laser diode
Main control panel with LCD

I added a couple of mechanical BCD switches

Not sure what else I've added or removed, but that is mainly it. This box has lots of stuff in it. Canada Post claims there was 6.159kg of electronic goodness in it when it was shipped to me - I'm sure it is more now.

I am currently looking for the next recipient - there are some suggestions in the logs, and there are many, many users requesting boxes online. I'll give it a week or so to see what falls out of the ether on its own before I start shoulder tapping.

Manned solar powered flight achieved today!

Wed, 07 Apr 2010 12:10:49 -0600

The news services are buzzing with word that Solar Impulse has achieved sustained flight. What is Solar Impulse? Amazing engineering.

A 1,600kg manned solar fueled electric powered airplane.

200m^2 of solar cells provide power to run 4 x 7,500W motors (peak output). The solar panels only receive 250W/m^2 on average throughout the day, so that means only 6,000W total (1,500 / motor) of continuous thrust is possible.

The article notes that the plane glided for 87 minutes. I believe the media is taking some literary license with the word 'glided'. According to the new release from Solar Impulse, the plane took off, climbed to 1,200m on a test flight to familiarize the pilot with the handling, etc. The news release says the flight lasted 87 minutes - so I don't think there was much gliding going on (certainly not during the climb).

The technical details that have been released are impressive:

TECHNCIAL DATASHEET
Wingspan:	63,40 m
Length:	21,85 m
Height:	6,40 m
Weight:	1 600 Kg
Motor power:	4 x 10 HP electric engines
Solar cells:	11 628 (10 748 on the wing, 880 on the horizontal stabilizer)
Average flying speed:	70 km/h
Take-off speed:	35 km/h
Maximum altitude:	8 500 m (27 900 ft)

Their ultimate goal? Fly around the world, including flying at night.

Wow.

Do not tail slide into the ground...

Sun, 21 Mar 2010 23:08:17 -0600

Had a great evening flying my Parkzone Citabria with a friend. He was just getting started with his Citabria and ended up sliding tail first down a net used as a wall. Something caught his elevator and stripped the servo - bummer.

Then I remembered all those Airhog toy R/C planes - they are only throttle and rudder! So we trimmed the elevator to stop the servo from whining and gave it a go. Worked like a charm! Now to be fair, he couldn't make nice gentle landings, and turning hard was out of the question, but he was back in the air and the evening wasn't lost.

So, to quote a TV great - "If the women don't find you handsome, they should at least find you handy.".

Citabria Upgrades

Sat, 06 Mar 2010 18:18:50 -0600

I received a larger battery for my Citabria last night (again thank you). It is a 138mAh battery and boy does it make a big difference. Not only in improved flight times, but in power as well. The newer battery must have a lower internal resistance, because I noticed improved climb rate and brighter lights.

The only downside with the larger battery is that it is larger. Meaning, it will not fit in the charger. Well, I fixed that. By cutting open the charging slot, I extracted the connector and now I can plug anything in!

I also reconnected the lights and swapped the yellow LED on the right for a proper green one. The green LED is not as bright and packaged differently, so it won't really help sorting my plane out from the crowd, but at least it is now running the correct colours.

Good to be back in the air

Sat, 06 Mar 2010 00:27:45 -0600

After a long hiatus, I returned to the air tonight. There was another Golf Dome fun fly events and with my Citabria repaired and no other events to hinder my schedule, off I went.

Got 3-4 good flights in, racked up another 30 minutes of air time and even managed a minor patch repair to get the lights working.

That repair will need some work, as I think a loose connection caused the receiver to reset. At home I redid the binding process and it was back to normal.

Anti-aircracft laser weapons rack up mig kills!

Fri, 12 Feb 2010 07:58:21 -0600

Want to see videos of lasers shooting down migs?

This website has some very cool slow motion videos of mosquitoes. The first couple are mosquitoes in flight - captured at 6000 frames per second! Very interesting to watch how the wings work - there are micro-ornothopter improvements in there somewhere.

However, the 3rd video is where the money is. Sorry PETA - there were mosquitoes injured and/or killed in the making of this clip - and it is awesome. As the mosquitoes fly by, a laser burns their wings off - some go limp and so presumably are killed before hitting the floor.

Probably not the safest idea, but if this laser is in any way actively targeting these little pests - whoa that's impressive....

For those who are slightly confused, migs are what my family calls mosquitoes.

Update: There is more details about the technology - these guys claim to have built a device with parts from eBay that identifies (right down to male vs female mosquitoes), tracks and fires upon the pests when they fly between two fence posts up to 30m apart!

Brain surgery - new receiver for the Citabria

Tue, 09 Feb 2010 20:28:14 -0600

Wow. I'm pushing my soldering skills to the limits. I just ordered and received a new receiver board for my Parkzone Citabria. See the rudder servo was damaged last year, and the plane was essentially grounded. The servo's are integral to the receiver board, and unless you are a jeweler by trade, not likely to be repairable. Here is the old receiver:

Last week I spotted a board on eBay for about 1/2 the regular price (including shipping) and decided to get the little guy airborne again. By the way - if anyone is interested, the old receiver board still works electronically. Battery cutoff, speed controller and elevator servo all work fine. Rudder servo motor and pot are fine - just the mechanics are damaged. Make me an offer - shipping to Canada or US is about $10.

When the board arrived, it had the battery connector soldered on - that was a good thing, and not so good thing. For now, it means my lights are not connected - daytime, low crowd flying only. However, the motor leads were NOT provided. I had to solder the motor to the two itsy-bitsy-teeny-tiny pads (no through holes) labeled M- and M+. Oh, and from a previous experience, I first tested the connections before soldering them backwards.... Here's the belly of the board:

Before soldering, I wanted to test the receiver. This requires binding the receiver to the transmitter. Unlike the old 72MHz days where a receiver and transmitter were configured manually to use a common channel, 2.4GHz equipment all share the same channel. They need to be programmed to listen to only the correct receiver - which is done through a process called Binding. It is quite simple. The Transmitter is started through a special configuration sequence - kind of like an Easter Egg and then the receiver is powered up.

For the Parkzone, you follow these simple steps (they are in the manual if you still have it lying around).

Turn off the transmitter.
Unplug the battery from the receiver.
Move the left stick to about the middle (not required, but makes the next step easier)
Press the left stick into the transmitter - it is a push button - and hold it while you turn the transmitter on.
The transmitter will enter a special binding state and start beeping continuously. You can let go of the stick and set the transmitter down at this point.
While it is beeping, plug the battery into the receiver. It will beep and eventually happy beeps all around will indicate the receiver is bound.
Throttle down, and confirm the right stick is working. Both servos should respond.

Once the motor was tested, and soldered, the receiver was placed into the plane. I used low temperature hot glue to secure the receiver in place.

The bottom servo is the elevator, and the top (the one that was damaged) is the rudder.

Inexpensive 400A DC Clamp meter

Fri, 29 Jan 2010 20:06:41 -0600

Canadian Tire of all places sells a must have tool for electric RC builders and pilots. A DC current meter that can measure over 10A. This is a clamp style meter (funny that the site calls is a Clap meter). It retails for $59.99 which is decent enough, but this week it went on sale for $20.99!!! Less than $25 taxes in gets a tool that can measure up to 400A of DC current! (BTW, it needs 2 x AAA batteries - the first time I've bought a meter that did not include batteries...)

I saw Mark from Cellar Dweller use one about a year ago to balance the up / down thrust of an electric heli and it immediately went to the top of my wish list.

So I just picked one up tonight and tried it out. It's no bazillion dollar Fluke(tm), but for $21 it works quite well. Measured the current draw on one of my planes @ 13.6A (11.1V - 150Watts!). (I think I saw a 16A on the first test, but too much stuff was blowing around the shop, and the battery in the plane was not fully charged.)

One a side by side test with an inline current meter (also Mastercraft), the inline measured 3.08A and the clap :-) meter measured 3.2A.

AC current test was measured while my furnace was running. The reference meter was a cheap (picked up on sale for less than $15 taxes in) PowerFist (Princess Auto) AC clamp current meter. It read 40.1A while the Mastercraft read 38.9A.

That's acceptable tolerance for my needs.

Furnace stats online

Sun, 24 Jan 2010 19:30:53 -0600

So I've been working on my furnace monitoring kit. And now I have basic weather logging enabled. I am fetching climate data from Environment Canada and adding it to a logging tool called RRD. This is a clever fixes size logging data store. It is meant for recording data on fixed time intervals. In my case I'm recording cycle counts, kWh used and outside temperature once every hour. It spits out graphs like this (hourly for 7 days):

I have created a full page to track weekly, monthly and annual usage.

There is a script (furnace.pl) constantly running that pings the microcontroller every second which returns the current status of the furnace (heating or not).

My crontab looks like this:

0 5 * * * /home/me/furnace/logparse.pl
5 5 * * * /home/me/furnace/hourly.pl
10 5 * * * /home/me/furnace/catchup.pl
20 5 * * * /home/me/furnace/enterdata.sh #legacy - generated by catchup.pl
0 6 * * * /home/me/furnace/fetchclimate.pl
5 6 * * * /home/me/furnace/graph.sh
10 6 * * * ftp -inv < /home/me/furnace/ftpscript #upload graphs to flyinglow.ca/furnace

These are works in progress. You can follow my furnace online (a_furnace).
0 0-23 * * * /home/me/furnace/twit.pl #tweet the daily usage up to the hour
0-59 * * * * /home/me/furnace/lcdstatus.pl #update an LCD display (and spin some servos)

Here is a zip archive of the scripts I created. They still need some polishing.

scripts.zip

DIY Humidifier

Sat, 16 Jan 2010 20:38:16 -0600

Ok, so last fall I had too much humidity (cool, damp summer), and now I don't have enough. Life in an older house in Manitoba....

So - one of the things I have done in the past is to reclaim the warm, moist air from the clothes dryer in winter. In my previous house, I had simply cut a bunch of slots in a 5 gallon pail, lined it with a piece of bulk furnace filter material and fed the dryer hose in through a hole in the lid. That worked, but was in the way and not easy to maintain.

This year, I bought a special valve for redirecting the warm, moist air back into the house. To trap the lint dust, I initially tried a water pail sold for that purpose - it's a small (2-3 litre) bucket that you fill with water. The hose is attached to the top and blows over the water - which is supposed to trap the lint dust. I wasn't impressed.

I liked the furnace filter idea better.

So, with the help of a friend who had way better wood working tools than I do, I built this fancy box that holds a 20x20x1 furnace filter.

In the winter I'll set the valve to redirect air into the house, and in summer it gets set to send the hot air outside.

When the filter gets full, its easy to slide out and replace.

Update (1/19/10): Humidity on laundry day jumped from just below 50% (we have had a mild spell which tends to not dry the house out as much) to nearly 60% by end of day. It has since (24 hours later) fallen to about 55%.

My furnace goes tweet!

Sun, 03 Jan 2010 20:23:39 -0600

So I probably should have spent my holidays getting my planes ready to fly, or my bike cleaned up and ready to ride (I have gained way to much weight since parking the bike at the end of October) - but instead, I worked on building a monitor for my furnace. I would like to know things like, how much money am I really saving by setting the thermostat back at night? How often does the furnace run? How long does it take the house to cool off at night before (or if) the furnace kicks in? and more!

I started a few weeks back and nearly had a permanent set back when one of the voltage regulator circuits I built blew up. Once I realized nothing vital was ruined, it was back at it. The circuits were completed - at least the prototype. Starting with the revamped power supply.

I made a few changes. Starting with the capacitor. Since blowing up a couple smaller ones, I researched proper sizing and most recommendations were to double the rating for safety - that is, 24VAC rectified into 35VDC meant the capacitor that filtered the DC supply should be rated for 70V. I actually had 1 cap that fit the bill. It is an old 330V 200uF cap from a camera flash I took apart almost 20 years ago (NEVER THROW ANYTHING OUT!). Next in the circuit was a voltage divider. With the 7812 damaged, I was down to a 7805 which would be working even harder to drop the voltage. Voltage dividers are a simple circuit consisting of 2 resisters in series. If the resisters have the same value, the voltage as measured in the middle is exactly half the supply voltage. I used 1.9K and 5.6K/3 (1.8K) - which results in a current draw of 10mA. Do not forget to take power dissipation into account! 10mA @ 35VDC is 1/3Watts. I used 1/2Watt resistors, and for the first resister I actually used 3 in parallel to share the load (the values where increased by 3 times). This circuit runs nice and cool.

The signal from the furnace / thermostat is also 24VAC. Not something to feed straight into a micro-controller. To isolate the signal and produce a more managable voltage, I used paper sensors from an old laser printer. These have an ir LED and photosensor nicely lined up. A resistor and LED in series with the line from the thermostat dropped the current to a safe level for the opto-coupler. I put a cap across the opto-coupler LED to try and smooth the pulses, but still needed to put code in place to handle the 60Hz flicker. This is packaged into a project box. The notation is C-common, Y-yellow (cooling/AC), W-white (heating), 5- +5VDC, G-ground.

The microcontroller listens on a serial line for a poke (the 'A' character) from the PC and returns a 1 or 2 if the furnace is on or off (0/1 caused Perl to think NULL/1 - sigh). Perl scripts on my shop linux box poke the microcontroller every second, log the results, summarize the information and update the LCD display every minute. As a bonus, every hour a tweet is sent out. Both the LCD display and tweet contain the total runtime of the furnace and the approximate power consumed since midnight.

A note about the power consumption. The furnace is electric. It has 3 x 4,800 watt elements that come on one at a time 60 seconds apart. So the scripts take the staging into account. Often, during the day the furnace only runs for 180 seconds at a time or less. Also, here in Manitoba the cost of power is currently $0.063 / kWh (1/4/10). I believe I have the scripts using $0.06 / kWh.

I'm not dead yet!

Mon, 21 Dec 2009 19:18:20 -0600

Well, seems that while I did do something stupid yesterday that did some damage, turns out the damage was not completely fatal to my project. The caps on the 7812 regulator could not handle something (voltage, current, power?) and let the magic smoke out with a vengeance! The prototyping board I was using was attached at the time (lesson learned - verify voltages and stability before connecting sensitive bits!). It stopped working. When I connected it to a stable source that was within tolerances, it decided to blow up as well!

Reverse view...

Thinking I was hooped, I set it aside and pondered my next move. Today I testing the LCD display hoping it was far enough removed to have survived and it had! Cool. While connecting it to the safe PC 5V supply I thought about the prototype board. The cap that was blown was related to the onboard 5V regulator. I wonder if the rest of the board worked -just not the regulator? See this board can accept 6-15V (not sure how much it took yesterday, but apparently more than 15) and then provides 5V to simple low power devices like the LCD display. I bypassed the regulator and supplied 5V direct from my PC to the board, connected the LCD and IT'S ALIVE!

Back to hacking!