Now that I got my ham license and some FPV equipment, I needed a way to set it up so that it’s usable at the flying field. Also, don’t let the title fool you – most of the money ($75) was spent on the FPV system itself, (including camera!). Other parts I was able to […]
Now that I got my ham license and some FPV equipment, I needed a way to set it up so that it’s usable at the flying field. Also, don’t let the title fool you – most of the money ($75) was spent on the FPV system itself, (including camera!). Other parts I was able to borrow or steal…
I started with the two-monitor portable DVD system that my kids use to watch movies on road trips. The 1st monitor is the “brain” that has the DVD player. The 2nd monitor simply accepts power and an A/V signal from the 1st. I stole this monitor for use with my ground station. I tested it by powering it on through the cigarette lighter jack and then hooking it up to the FPV receiver. With the FPV transmitter off I saw static instead of the dreaded “blue screen” – which is good!
I have a tripod that I rarely use, so I set about to fasten the monitor to it. I cut a piece of plywood to match the shape of the tripod quick release. After testing the fit, I glued it to a slightly bigger piece of plywood that would serve as the mount for the monitor.
I added 3M Dual-Lock (much stronger than velcro) strips to hold the monitor to the mounting plate. Then it can sit on the tripod, and the headrest straps can go over the mount for extra insurance.
Rather than trying to find a compatible power jack for the DVD monitor, I decided to instead to cut the original cable and splice in a JST connector. That way the cigarette adapter can stay in the car and I can poach the monitor and cables for an FPV flight.
To power the ground station I’m using a cheap 3S battery that I already had. I fastened it and the FPV receiver to the back of the monitor. A JST “Y” cable was all that was needed to complete the wiring.
To complete the setup, I crafted a monitor hood out of Dollar Tree foam board – the black stuff. I cut a standard top rectangle and side triangles, and then made some “hooks” to hold the hood on the corners of the monitor.
If you’re interested in specifics about the foam board hood, let me know in the comments!
I finally jumped into FPV by purchasing my first kit, a Quanum Tx/Rx/Camera package I got for around $60 from HobbyKing while it was on sale. With it’s 600mW transmit power, it should be more than enough for some field flying, even with trees in the way. But before I fire it up, I needed […]
I finally jumped into FPV by purchasing my first kit, a Quanum Tx/Rx/Camera package I got for around $60 from HobbyKing while it was on sale.
With it’s 600mW transmit power, it should be more than enough for some field flying, even with trees in the way. But before I fire it up, I needed to get legal. The FCC has a rule called Part 15 about “unlicensed equipment” which states what sort of emissions a device can have to be operated without a radio license. It’s rather complex and the only FCC Part 15 certified FPV systems I’ve seen are 20-25mW. So it was time for me to ante up and get my amateur radio license so I can be a legal, card-carrying operator.
To study for the technicians test, I got this book at my local library:
It was decent. With zero investment I was able to pass my technician’s license exam on the first try – so that’s a thing.
Regarding this book, even though it is a third edition book, it has some editing problems. Often acronyms are used before they’re defined. If you’re a newcomer to amateur radio, be sure to keep one finger tucked in the glossary. Don’t bother looking back to see if you missed it earlier, chances are you didn’t.
Oh the Vanity!
After passing my exam, I decided to go one step further and get a personalized “vanity” call-sign:
Same as my last name. It works out nicely because as a technician, my call sign must be K or W, a letter, a region number, followed by three letters. Zero (0) is the region I live in, so putting my name in my sign was a no-brainer
Plus as card-carrying ham radio uber-nerd, I doubled-down on my vanity and got a license plate:
They’re quite a deal – $100 less than a run-of-the-mill personalized plate, plus it’s worth at least 100 points of geek credibility!
While this isn’t about anything R/C, it’s somewhat related… I recently converted a lead-acid battery powered mower to lithium-ion batteries. Anyone that is in R/C and has a lawn to mow should follow this course. For the record, I hate mowing the lawn. It’s a useless pursuit. We’ve all got better things to do with […]
While this isn’t about anything R/C, it’s somewhat related… I recently converted a lead-acid battery powered mower to lithium-ion batteries. Anyone that is in R/C and has a lawn to mow should follow this course.
I purchased a used electric mower with a bad battery off of craigslist for $20. If you don’t find any on craigslist, put out a wanted ad – you’ll be surprised at how many people will see it and heed your call. You can do research on specific models if you’d like, but you’ll want is to make sure it’s 24-volt. We’ll replace the two 12-volt batteries with one or two 6-cell (6S) Li-poly batteries, which have a working voltage of 25.2v (fully charged) to 18v (fully discharged). You can review other features on sites like amazon, but many have terrible reviews because the lead acid batteries only last about a year before giving up the ghost. Don’t worry, that’s what we’re going to fix!
Converting a lead acid battery powered mower to LiPo is surprisingly easy. On the Remington model I purchased, it had a handled basket to remove/install the battery pack into the mower. This basket will still be useful to bring the batteries inside for charging, and to store them indoors during the winter.
To start, I took the basket out and disassembled it to remove the lead-acid batteries. I left the lid off which contains the lead-acid charging circuitry – which we won’t need.
I put some foam at the bottom of the battery container. The LiPo batteries won’t need nearly as much space as the lead-acid ones did.
As a curiosity, I looked under the cowl of the mower and it was dead simple. A total of 3 wires – battery negative straight to the motor, battery positive to the handle switch, and the return from the switch to the motor. That and an electric motor the size of a chunky soup can was all that is under there. No speed control, just on or off.
On my first test the mower worked great. The low-voltage sensor seemed to beep a couple false-positives, possibly due to the amp draw from the ungoverned motor. To prevent excessive beeping, I set the cut-off to 3.0v per cell. On my particular alarm, it means it will start beeping when one cell gets to 3.09v or lower.
This just means that I have to shut it down right away when it beeps, but I’m less likely to get any annoying false-positives. I got 19 minutes of run-time on a single battery. The single battery pack did seem to get pretty warm. If I calculate that the entire 5.2 amp-hours had been depleted in that 19 minutes, the current draw would be around 16 amps. This jives with specs that I’ve read about most electric mowers drawing 18-20 amps.
A 16-amp continuous draw is far lower than the battery packs 52-amp 10C constant-discharge rating (5.2Ah x 10C = 52A). Still the heat concerned me, and I could only get the front yard and 1/3 of the back yard done in those 19 minutes.
With two batteries, heat is reduced and I get 36 minutes of runtime – just enough to mow a 1/4 acre.
Cost & Upgradability
Even if I didn’t already have a charger & power supply, those cost about $80 together. Add $60 for batteries, cables, and connectors, plus $25 to ship it all from China. Along with the $20 I paid for the mower, at $185 it’s cheaper than any new lead-acid battery-powered mower and it will run longer, lighter, and more consistently over a longer life-span.
Plus, I’m not limited to what batteries it can take. As battery technology becomes better, cheaper, and smaller I’ll be able to upgrade and get more bang for my buck when the current LiPo power-packs reach end-of-life.
If you don’t actually have a lawn to mow, enjoy this flying lawn mower instead:
My Assault 100 helicopter came with a transmitter module that allows you to use it with any transmitter. This module is also used with HobbyKing’s Q-BOT Micro quad and FBL100 helicopter. It’s actually just a rebranded HiSky HT8 module which is used for many HiSky helicopters. Rather than have to charge this module separately and hang it […]
My Assault 100 helicopter came with a transmitter module that allows you to use it with any transmitter. This module is also used with HobbyKing’s Q-BOT Micro quad and FBL100 helicopter. It’s actually just a rebranded HiSky HT8 module which is used for manyHiSkyhelicopters. Rather than have to charge this module separately and hang it off of my Turnigy 9x, I decided to build a module specifically for my 9x which would power it up and keep it safely in place.
To begin I unscrewed the HT8 transmitter case and removed the included lipo battery. I then de-soldered the battery connector and the antenna.
With the transmitter circuit board in hand, I could test fit it into the module case. To fill in the space I added two layers of dollar tree foam board cut to fit.
I aligned the circuit board vertically with the on/off switch upwards. So the lid wouldn’t crush the on/off switch, I had to remove some gusset material at the top. To get the case lid to close I would only be able to use 3 out of 4 of the case screws. In the photo, you can see where I used a dremel to remove one of the case screw posts at the bottom of the module. I also drilled a hole to be able to push the mode button on the HT8.
To get the molex connector just right, I dremeled out the holes where the pins normally go through the module case, enough to fit the molex connector through. I snapped the back half of module case into my transmitter, slipped the molex connector over the pins, and used hot glue to hold it into place for perfect alignment.
I arranged the molex pin colors the following way from top to bottom:
Unlike the RCGroups write-up, I decided to solder directly to the 3-pin header rather than the bottom of the circuit board as I felt it was easier. I soldered the ends of green and black together and then soldered them to the pin closest to the middle of the board. I soldered the white wire to the pin closest to the edge of the board. I soldered the red wire to the middle pin.
I cut the connector off of the included antenna cable and carefully stripped the cable to separately expose the shielding and core wire. Then I soldered the antenna onto the HT8 module board in the same manner as the included antenna (see the opened HT8 image).
With everything wired up I was ready to pack it in and fasten it shut. To be clever, I used a dab of hot-glue to tack the included button extension to the mode switch on the HT8. The button extension would go through the hole I drilled in the case for ease of use.
The button with the extension wound up being a problem as it protrudes from the module quite a bit. Pressing the mode button switches the HT8 between Futaba, JR, and Walkera modes. Changing modes while a model is active reassigns the channels which can (and will) produce unexpected things to happen. If you set down your transmitter, there’s a good chance this button will get pressed. If your model is on, it will likely do something unexpected that may result in breaking and/or injuring someone
So I removed the button extension, opting instead to switch modes (which will likely only be required once) by using a small screwdriver.
I’m new to helicopters, so the setup was a little daunting – especially given the fact that my transmitter has an alternate firmware (OpenTX) installed, and the Assault 100 printed manual settings for the Turnigy 9x assume you have stock firmware. One other important detail I didn’t understand is that flybarless helicopters don’t use the […]
I’m new to helicopters, so the setup was a little daunting – especially given the fact that my transmitter has an alternate firmware (OpenTX) installed, and the Assault 100 printed manual settings for the Turnigy 9x assume you have stock firmware.
One other important detail I didn’t understand is that flybarless helicopters don’t use the helicopter functions built into the transmitter. Instead they have something similar to a quadcopter flight controller with gyro sensors to perform the stabilization function of the flybar. Rather than setting up the swash type and assigning the cyclic channels on the radio, the cyclic inputs can be sent as normal aileron and elevator controls – similar to a multi-rotor.
What still needs to be set up on the transmitter is the channel assignment, throttle and pitch curves, and reversing. That last part is extremely important and is how I broke my helicopter before it ever left the ground
I recommend that before you do any of this you remove the main rotor blades. While this helicopter is very small, a lot can happen fast and repairs on this tiny beast can be difficult.
This guide assumes you’re using OpenTX version 2.1 on your transmitter. Earlier/later versions may have different screens and options.
Start with a blank model. The Assault 100 manual and HCP100S manual provides some sane, but confusing default settings. Things like recommended endpoint percent vary from settings for the RTF radio, Spektrum, Walkera, Futaba, and Turnigy 9x (assumes stock firmware). However, it recommends 70% rudder for all models. Elevator and aileron endpoints are typically the same or within 5-10% of each other, with elevator usually being a little higher.
I took the 9x recommendations from the manual as slightly deadened sticks may help keep me out of trouble:
Then go to the templates screen and apply the Heli Setup template.
You’ll have to “undo” some of the settings from this template, but it will give you a good starting point for curves and mixes. The first thing we need to clear are the standard flybar/cyclic settings. Go the Heli Setup screen and clear the Swash Type and Collective settings so it looks like this:
Then go to the Mixer screen and clear the cyclic settings from channels 1-3.
When the transmitter module is in “Futaba” mode (both green lights), the channels that that it receives from my OpenTX 9x and sends to the helicopter are as follows:
CH5: Gyro Gain (as a beginner, I’m not exactly sure how this effects flight characteristics)
CH6: Collective Pitch
Knowing this we can assign the channels in the mixer screen as they should be. You may have to move some things around as well. After clearing cyclic 1-3 I assigned CH1 to aileron and CH2 to elevator. Then I moved the throttle settings from CH5 to CH3.
Also from the stock setup, I changed the throttle defeat to be !THR – I do this on all of my models. The radio will complain about the throttle arming switch when it’s towards the pilot at power-up. I find it dumb that in default OpenTX mixes, the switch towards the pilot is Safe/Off. Wouldn’t you want the transmitter to warn you if you turned it on and the throttle was armed?
Throttle & Pitch Curves
I didn’t deviate from the Heli Setup template for my curves as they’re pretty close to what the manual recommends. Plus there’s a “beginner/start-up” throttle and pitch curves on CV1/CV4 (respectively). To start I’m for sure going to be using the “beginner” curves that are activated when the flight mode switch is at “N” (ID0). The start-up throttle curve looks like this:
The start-up collective pitch curve looks like this:
With the helicopter on (but main rotor blades off!) and the throttle disarmed you can move the cyclic (aileron/elevator) stick to make sure the cyclic is going in the direction you want. It’s easy, when you stick left the right side of the cyclic should rise, making it look like it’s trying to roll to the left. Stick up should raise the back of the cyclic evenly, making it look like it’s trying to go nose-down.
Collective pitch helicopters are interesting/complicated because the throttle control serves two functions: controlling the throttle (duh), and controlling the pitch of the main rotor blades – sometimes referred to just as the pitch or collective for short. These controls must also work in cooperation with each other.
The key to understanding how to set this up in the transmitter is understanding OpenTX mixes. Basically we can create mixes that assign what the physical control sticks will send to the model. The throttle stick in our case needs to control the throttle as well as the collective pitch. CH3 in the mixer screen is bound to the throttle stick and the throttle curves. Also, CH6 is bound to the throttle stick for pitch curve, so when I move the throttle stick up and down, the pitch curve signal goes out on channel 6.
To test the pitch, put the blades on and turn the helicopter on, but leave the throttle disarmed. Moving the throttle stick should up should make the leading edge of the blades point up. If they go down when the stick goes up we need to do some reversing. But first an anecdote…
The reason I initially broke my heli was because on first flight my throttle was reversed. How I arrived at this was because the collective was moving in the opposite direction as I expected. Rather than reversing the collective (CH6), I reversed the input of the throttle channel (CH3). Reversing the throttle fixed the collective direction, but also reversed the throttle. When I armed the throttle this resulted in 100% speed. I would have had to move the stick all the way up to put the throttle at 0%. At a time when the helicopter is flailing wildly it didn’t occur to me – only after it was broken did I realize my folly.
Let me reiterate – reversing CH3 in my setup reversed the throttle and the collective pitch. To reverse just the collective pitch I needed to reverse CH6. Reversing the collective pitch and throttle channels in various combinations should help you get your settings in sync. To get them in sync, the best way I found to test this is by viewing this screen on the transmitter with the throttle armed (and the helicopter unplugged):
In my case the bars needed to move in the same direction: to the left as the throttle went up. Hopefully this provides some insight not only for those looking to set up their CP Heli with OpenTX, but how OpenTX functions in general.
I’m a sucker for deals at HobbyKing, and I’d been looking at small collective pitch helicopters for a while. When the Assault 100 went on sale for less than $50, I jumped on it. Before I purchased, I did some research and found that it’s really just a rebranded HiSky HCP100S. I found some generally positive […]
I’m a sucker for deals at HobbyKing, and I’d been looking at small collective pitch helicopters for a while. When the Assault 100 went on sale for less than $50, I jumped on it. Before I purchased, I did some research and found that it’s really just a rebranded HiSky HCP100S. I found some generally positive information online, but maybe I should have read this entire 300+ page thread about the HCP100S before I pulled the trigger. Let’s find out…
As with many of the great things we get from China, documentation is lacking. Luckily, there’s a guy at the local electric fly R/C club who’s an experienced collective pitch pilot and could talk me through some of the setup. I’ll be doing a separate post just for the transmitter settings.
Something I can absolutely confirm from that RCGroups.com thread is there definitely is an issue with it tilting before take-off. Case in point, my maiden flight and everything leading up to it:
Getting it into the air for the first time takes a commitment that a beginner (like myself) may not have the fortitude for. Frankly, this is the most disappointing thing about this helicopter. As a beginner I couldn’t follow a normal progression of maneuvers while light on the skids before taking to the air. Possibly it is part of the flybarless system creating a ground induced feedback – the problem goes away once airborne.
Some people in the RCGroups thread talk about the tilt issue being due to a “bad bind” with included transmitter module. I’ve experienced something slightly different… occasionally after helicopter binds at startup, it will not react to aileron input, just elevator. I’ve never tried to take off in this state, I just unplug and replug the battery to get a “good bind.” I always check all the controls before arming the throttle.
Once the nerve-wracking take-off is behind you, it behaves nicely in the air. Heading hold seems to be very good, even on windy days. I haven’t flown it in idle up, mostly because I don’t have the guts yet, but I get about 10 minutes of hovering time in normal mode, which has the throttle around 65%.
I have done the “rubber band trick” to keep the skids in place. They press in, but don’t snap in and with the weight of the battery connected, it’s easy for them to come loose on hard landings and mild crashes, quickly making a mess resembling a yard sale.
I’ve thought about trading in the Assault 100 for something a little easier to fly like the Blade Nano CPS – especially since the normal price point of $100 is the same as the Assault 100. But the guys at Flite Test had a less than stellar experience:
I like being a helicopter parent – no not being overprotective and smothering – I just like flying helicopters with my son. For Christmas I got Jules a Blade Scout CX coaxial helicopter. It’s a great helicopter for anyone to start on, including a pre-schooler. It has a gyro and stabilizer bar to keep it […]
I like being a helicopter parent – no not being overprotective and smothering – I just like flying helicopters with my son. For Christmas I got Jules a Blade Scout CX coaxial helicopter. It’s a great helicopter for anyone to start on, including a pre-schooler. It has a gyro and stabilizer bar to keep it level, and the 3-channel remote is easy to use for a beginner. Even when he’s not flying, Jules likes to “scoot” the heli around on the kitchen linoleum by giving it just enough power to get the helicopter light on the skids – then sliding it around on the floor without leaving the ground.
In the winter Jules and I went to a few dome flys with a local R/C club called MARCEE. In the wide-open space at the dome, it’s good to have a something to aim for. I had a couple of large-ish pieces of foam that were used shipping my R/C car set-up board. To give them a little more realism as helicopter landing pads, I added a circle “H” to each.
I started by looking to the interwebs for inspiration and found some good vector art helipad examples. After finding one I liked, I printed it onto a normal sheet of paper and then cut out the shapes using an x-acto knife to use it as a stencil. Remember to not fully cut out any circles – keeping the stencil as one piece will make it much easier to use.
For the paint, I went to Michael’s and bought two of the cheapest acrylic paints they had. With my stencil taped on to my landing pad foam, I painted the stencil areas using a sponge brush. This gave a similar effect to the graphic I found. For more solid colors, you may choose to use a spray or a regular brush.
The result was pretty good, took less than an hour and cost less than $5.
A year and a half after I purchased these bags, it’s time for a review. You can’t buy them anymore, but this is more of a review of panniers in general. I used to ride with a backpack. It works (and is good for laptop shock absorption), but be prepared to have an instantly sweaty back. I can’t walk up a flight of stairs with a backpack on and not start to feel damp 🙂 Getting the bag off of my back and on to the rack on my bike is a huge win for comfort and convenience.
These Thule bags were a steal at $120 for the pair. Most decent panniers cost this much just for one! They were a deal because Thule discontinued this model. The replacement bag is a “unidirectional” one that can go on either the left or right side of the bike rack, whereas the ones I got are specifically made for left and right sides – they are slightly narrower towards the front of the bike.
The Thule bags have a pretty rad feature where you can “flip” and hide the rack attachment hardware and carry it as a normal-looking handbag, or add the included strap and wear it as a shoulder bag or backpack.
With my new job, I use one everyday to carry my laptop to work. The other bag, sadly sits idle most of the time as I only need one for what I’m carrying. They came as a pair and at the time of purchase I was thinking about all of the epic bike adventures I’d be going on, with both bags packed to the hilt. Carry all the things!
I will use both for something like another bike camping trip, but for day-to-day commuting, just one is great.
I have racks on both my road bike and my mountain bike (which is really more of a kid-hauler than a mountain bike). I like my Topeakracks because they have a secure mounting system and Topeak offers severalattachments. The Thule panniers fit nicely on both of my racks despite their differing thickness of tubing. You cannot, however, attach a top mounted Topeak trunk bag and the panniers on the side at the same time – they interfere with each other. I plan on devising something that can go on the top while both panniers are on with some spare parts, but that will have to wait for later.
100 years ago, when spinning hard drives in laptops were the norm, there were several creative ways to carry your laptop in a pannier. Solutions from suspension to excess padding were employed to ensure you didn’t jar the hard drive beyond its shock tolerance. I’ve gone the other way and simply purchased a laptop with a solid-state drive instead of a spinning disk. I lined the bottom of my panniers with a bit of bubble-wrap left over from a mailer, just to prevent any dents when I’m doing sweet jumps.
While the bags aren’t waterproof they come with a waterproof cover. I’ve only used the cover once (in a total downpour). Normally I can just ride home quickly in a sprinkle, because it’s only one mile to work 😎 The covers stow inside each bag and are easily added: