Lake Sensor Project: Bill of Materials

Hardware top level description:

This project consists of two main hardware assembles:
1) Sensor package attached to dock with wireless data transmission
2) Wireless data receiver module attached to PC

I used the Arduino because I had one on hand. This particular model isn't manufactured any longer, but any of the newer models should work fine.

There are all kinds of rube-goldberg ways to measure lake level. I felt an ultrasonic distance sensor would be a good way to measure the lake level with no mechanical complexity. They are also fairly cheap, particularly off of Ebay. The HC-SR04 didn't have great examples online on how to implement the code, but I used some code examples off of Adafruit's excellent website and modified them for the 4-pin HC-SR04 vs. the models Adafruit carries.

The other sensors are pretty self-explanatory, I chose them for a nice balance of price vs. accuracy.

I had a hard time deciding whether to go with wireless data transmission, or wired. There are several ethernet options available for arduino boards, some of which even support power over ethernet (POE). POE would be particularly cool, since then I wouldn't have to run separate power and data lines down to the dock. POE vs. XBEE data transmission were about the same price. The decision point for me was lightning risk- running an ethernet cable down to the dock would expose my home network to a might higher risk of damage from nearby lightning strikes.

The enclosure is off the shelf electrical components from Lowe's.

Sensor Package Bill of Materials:

Item	P/N	Source	Quantity
Arduino Duemilanove	N/A	www.adafruit.com	1
Ultrasonic distance sensor	HC-SR04	www.ebay.com	1
Precision Epoxy Thermistor	N/A	www.adafruit.com	1
Air Temperature / Humidity Sensor	DHT22	www.adafruit.com	1
Photocell	N/A	www.adafruit.com	1
X-Bee Shield	WRL-09976	www.sparkfun.com	1
X-Bee Pro, Series 1 wireless data module (100mW power)	XBP24-AWI-001-ND	www.digikey.com	1
Printed Circuit Board, general purpose	276-150	Radio Shack	1
6"x6"x4" PVC outdoor wiring box	N/A	Lowe's	1
Redodot wet locations hinged outlet cover	N/A	Lowe's	1

Note: many misc. components were not included- headers to solder on to X-Bee Shield, ribbon cables, connectors, etc.


Wireless Data Receiver Bill of Materials:

Item	P/N	Source	Quantity
X-Bee Pro, Series 1 wireless data module (100mW power)	XBP24-AWI-001-ND	www.digikey.com	1
X-Bee Explorer USB	WRL-08687	www.sparkfun.com	1

Initially this data receiver will be used bare, but eventually it should be placed in an enclosure and placed somewhere safe and out of the way.

Lake Sensor Project - Sensor Package Installed!

It's been a while since my last post. We've been very busy with the new baby. Every once in a while I've been able to sneak off and work on my new project- a sensor package to remotely monitor various environmental states of Mooney Lake. I've finally be able to get it up and running, and it's now attached to the side of the dock and transmitting data.

Goals:

• Remotely monitor lake level, lake water temperature, air temperature and air humidity. I also attached a photocell to measure ambient light levels just for the heck of it.
• Log the data, push it to the "cloud", and graphically display it on the Mooney Lake website. 

Current Status:

• The sensor package appears to be working, and it's transmitting data to my laptop in the house.

Next Steps:

• Write some code in Processing or Python (I'm not sure which yet) to push the data to Google Docs. My initial plan is to use Google Docs to log the data and generate graphs depicting trends over time. I'm hoping this will be the easiest method to create graphs that I can then pull into the Mooney Lake website. An alternative would be to directly create the graphs using Processing, save this as a .jpg then drive the .jpg to the Mooney Lake site.

Sometimes lunchtime flying doesn't go as well as you'd like...

I had some not-so great results flying today at lunch. I switched the P-51 out to a 8x8 prop last night. I had one good flight- and man, was it awesome. The amount of extra speed generated when I transitioned from a 10x5 to a 8x8 was amazing, and it still pulled just under 60A in static full throttle testing. That airplane was totally ballistic. Very solid, maintained speed extremely well, and the highest top speed I’ve seen yet. Probably even faster than last summer when I flew it a few times with John's 1550 mAh 4s battery. Well, on flight #2 I didn’t get a good enough launch, stalled it, and pile-drived it into the ground under full throttle. I haven’t determined if it’s fixable or not, but the fuse broke in 2 places, munched the prop to stubs, and possibly cracked the wing. One take away is that launching with a smaller diameter higher pitch prop is more challenging, as it doesn’t accelerate out as quickly.

Then, I turned to the babyshark, and did almost exactly the same thing. Poor launch, stall, almost recovered it, regained enough altitude so when I lost control it nose-dived into the ground at high velocity. The damage isn’t too severe- separated the firewall from the nose, and crunched the forward bulkhead. I’m also not sure about fixing this again. I feel like I should continue to fix, fly, and repeat until I get at least one passable flight, but I am getting a little discouraged. Next time I’m going to try flying it with a smaller battery to lower the stall speed.

Surly Big Dummy mini-Review

Last week I sold my cyclocross bike / commuter and bought a 2011 Surly Big Dummy. Crazy, I know, but I thought it would be sweet to have a bike that would allow no excuses not to run all possible errands on the bike. Considering the Big Dummy has a listed cargo weight limit of 200 pounds, even picking up four bags of water softener salt is a doable errand.



So far I've only ridden it home from work and one trip about town and back home from the grocery store. The photo above shows it fully loaded with the items below. During this last trip I carried:

• 21 pound bag of cat litter
• 2x 12-packs of coke
• bag of misc. groceries and cleaning supplies.

Not bad for a first trip. This bike handles surprisingly well even with a fair amount of weight. On the way back we detoured through some rougher bike trails and it did well. I'd consider even trying to ride Theo on it, although popping the front wheel over obstacles would be challenging to say the least!

My only negative so far is that when in the granny gear the two mile long chain drags across one of the frame members. I'll have to get some clear protective tape or old tire sections to protect the steel.

Another bonus is it may be possible to run snow bike tires and rims on this beast- with the super long wheelbase I bet it'd be very stable on rutted-out snowy trails.

Father's Day Flying

John and I were able to get out on some fun and destructive flying last night. Key flights include the maiden of my Balsa Baby Shark ( and promptly put it back in the shop ), and John's encounter with the Vortex of Doom with his E-Flite T-34.

Balsa Baby Shark

Looking at the video, I didn't have a very good launch. I did a weak toss better suited for an overpowered beast like my PZ P-51. I didn't dare launch the Babyshark at full throttle- so it was no more than 1/3 throttle during the entire short flight. I think it needs a hard, flat hand launch. Next time I'll also try it during a time when half the pattern isn't into the sun either. Luckily the damage was minor- broken prop, and the forward bulkhead was crushed by the battery. Both easy fixes. 

T-34 Aftermath

John's T-34 might not be quite as easy to fix....

But, I did manage to get the best flight out of my Tricopter yet.

 

The electronics seem to be pretty well sorted out. The tail rotor yaw mechanism isn't as robust as I'd like, and I also need some better visual markers to tell which way is "front".

Tricopter DX6i, AR6110 final setup

After lots of experimentation, I finalized my tricopter setup. I was origionally working from the setup guide on RCexplorer.se's website. His setup was for Futaba radio systems, and since I am using a Spektrum DX6i and a Spektrum AR6110 receiver my setup turned out to the slightly different.

These settings seem to work fairly well- it's obvious the limitations now are my piloting skills. I really need to attach a body or something so it's easy to tell which end is "front"- it is very easy to lose directional orientation!

NOTE THESE ARE DIFFERENT SETTINGS THAN MY EARLIER BLOG POST!!! I kept the original blog post active for reference only

AR6110 Receiver Connections:
(note gyros are in-line with connections between receiver and ESC or servos)

Channel	Receiver Label	Servo / ESC
1	Throttle	Tail rotor gyro gain
2	Aileron	Left rotor ESC
3	Elevator	Tail rotor ESC
4	Rudder	Tail rotor servo
5	Gear	rotor gyro gain (split 3 ways)
6	Aux	Right rotor ESC

The tail rotor gain is attached to the Throttle channel. If you had a 7 or more channel radio, you could attach this gain to another auxiliary channel with a seperate switch. Since I only have a DX6i I don't have this luxury. Since the radio is in helicopter mode, you can set your gain using your throttle curve. It's a pain to adjust your gain, but it works. To change your gain you have to adjust the throttle curve across all points- meaning each time you have to change the gain you change each of five location on the throttle curve to the gain setting you want.


DX6i Setup after several somewhat successful flights
(I need to work on my multi-rotor heli skills!)


Adjust List

Throttle Curve (tail servo gyro gain) = 95% (heading hold mode) at all points
intent: if gain is 0-50%, gyro is in rate mode. if it is 50-100%, it is in heading hold mode. The intent here is for the tail servo (yaw) gyro to be in heading hold mode. As far as I understand, lower numbers = higher gyro gain. This setting seems to produce a pretty rock solid heading hold, perhaps a bit of over correction.

Gyro: (gain for the 3 ESC gyros) = 35%. Seems to be fairly stable without too much overcorrection for my setup. Again, keep it under 50% so it is in rate mode, and lower numbers equals more gyro gain. Since the radio is in helicopter mode, the gyro adjust changes the "gear" output on the receiver.

Pitch Curve (normal)

Position	Setting
L	0%
2	40%
3	50%
4	70%
H	100%

Dual Rate & Expo

Function	Mix
Aileron	80%+20%
Elevator	70%+20%
Rudder	94%+inh

Swash Mix

Function	Mix
Aileron	+40%
Elevator	-40%
Pitch	+100%

Setup List

Reverse

Function	Reverse?
Throttle	N
Elevator	N
Gyro	N
Aileron	R
Rudder	R
Pitch	R

Swash Type
CCPM 120 degrees

Why isn't balsa more popular?

Since Anna's been going to bed early every night because she is working hard growing a baby, I've had time to work on a number of different projects. I think people avoid balsa kits because of the time required for assembly- especially compared to quality balsa or foam ARF models - but I think there is a lot of satisfaction in actually building something. I also seem to have more time available at night at home vs. time available to actually go flying. For a beginner, though, nothing beats a foam ARF which you can repair in ten minutes with hot glue and packing tape. Balsa is a lot less forgiving.

Nanoplanes.net Balsa Baby Shark



This is a first class product. (and I haven't even flown it yet) Top quality instructions, clever design and easy construction. In particular I really liked how they have you laminate different pieces of wood together with alternating grain direction for maximum strength. This should be an absolute rocket, I'm hoping for 100+ mph top speeds. I won't maiden this until I can have John help me trim it out at a large field.

In static testing the motor pulled 26.5 amps with a APC 4.75 x 4.75 prop.

Components Used:

• Spektrum AR6110e receiver
• 30mm spinner
• 24 gram 3000 k/v brushless motor
• APC 4.75 x 4.75 prop
• Turnigy 30A ESC
• 3x HXT500 5 gram servos (modified from stock 2 servos)
• Turnigy 1300 mAh, 3s, 30c lipo battery
• Coverite transparent yellow iron-on covering
• Transparent + black checkerboard trim

Mountain Models Mini-Flash



This was a fun build. All precision laser-cut balsa, the kit included a very complete hardware package.

It went together fairly quickly. The directions were not quite as good as the Baby Shark, and it would have been helpful to have alternative motor mounts available. The plane was designed for a GWS gear drive system with a stick-mount. I used a brushless motor, plus a home-made delrin adapter plate to allow the use of an E-flite brushless stick mount. Mountain Models should also consider updating their instructions to match kit contents better- the instructions state Doculam covering is included with the kit, but it wasn't in mine. Note I didn't mind, as I didn't intend to use that material anyway.

I also had some trouble getting the CG to line up right- perhaps I used too heavy of a covering or excessive glue in the tail. I'd also recommend NOT using CA to fasten the canopy in place- the CA fumes deposited white residue on the inside of the canopy and on my pilot.

However, the end result looks good and flies great. Extremely acrobatic, and I'm still using the recommended low rates. High rates are insane, I'll have to get in some serious practice before I'll be able to fly using them. I also really like how the transparent yellow wings look when in flight.

Components Used:

• Spektrum AR6110 receiver
• 2213n 800 kV motor- I originally intended on using this 1200kv motor (previously well used on other aircraft), but accidentally broke several wires when installing the motor. I had this 800 kV motor as a backup for my Tricopter motors, but thought I'd put it to good use here.
• APC 10x4.7 SF prop. This only gives about 10amps- I will try larger diameter and higher pitch to try and bring this closer to 18amps at full throttle. I'm thinking an 11x7 SF might be a good choice. Even with the 10x4.7 prop the aircraft has nearly vertical performance, and nice long flight times.
• Turnigy Plush 18A ESC
• 4x HXT900 servos
• Rhino 750 mAh, 3s, 20c lipo batteries
• Coverite transparent yellow iron-on covering
• Blue econocote iron-on covering

E-Flite Funtana 300
I purchased this acrobatic foamie from Mark last year. It had an unfortunate crash this past winter- nose-first into the ice. I patched it back together with balsa, but it really hasn't flown the same since because of the added weight from all the balsa and epoxy patches. When I built the Mountain Models mini-Flash, I removed the Funtana's Spektrum AR6110 for the new plane. I did purchase a few of Hobbyking's new RA61E 6 channel 6110 knock-off receivers. I was a little skeptical about their quality so I certainly won't put one in a balsa model, but it was a perfect receiver to put in the Funtana which is now somewhat disposable. I flew it for a couple batteries last night, and the cheapo receiver seems to bind and function just like the AR6110 origional, but only 25% of the cost.