Posted by mnemennth |
Dec 08, 2013 @ 03:23 PM | 836 Views
We have a LOT of smart and inventive folks here on RCG; by the nature of the hobby, we encourage experimentation and customizing electronics is at the heart of nearly everything we do. As a result, it is easy sometimes to forget how dangerous electricity really is; and this is very visible in several very popular threads on modding Computer/Server Power Supplies for use with RC gear.
Now I have made oodles of these modded power supplies; I've done nearly every hack imaginable, and I've been doing it since I was a teenager. I'll admit... I've done some pretty dangerous mods, and have some scars to prove it; now I'm trying to pass on what I've learned by painful experience. I have dozens of re-purposed power supplies in my home right now, and even one or two that operate on the same principle of connecting two power supplies in series as is the point of this article.
My main concern, the reason for posting this blog, is the practice of creating a 24V high-current power supply by series-connecting two 12V power supplies and making the "Isolated PCB" or "Floating Ground" mod as is outlined in many of these threads. The "Floating Ground" mod is, in my opinion, simply unthinkable; having the metal case ungrounded of a power supply that can carry more than 400 volts inside is beyond foolhardy. It BEGS fate to adjust one's pain threshold in a very possibly fatal manner. This practice REALLY is a Darwin Award waiting to happen.
UPDATE: "TOY" HELIS AND PLANES AND CARS VS LIPO SAFETY
In the last few years, China MFRs have flooded the market with every imaginable kind of remote control toy vehicles; as these toys grow larger and more sophisticated, so increases their reliance on LiPo batteries as a power source. MANY of these devices are based on recycled Ni-Cd or Ni-Mh powered designs; as such, they don't have low-voltage monitoring or shutdown circuitry to prevent damage to the battery.
With Ni-XX based packs, this just costs you a replacement battery (Yay! Battery sales!); with LiPo batteries, it can cost you your home or your life. When LiPos are discharged too low they can catch fire, and this process may start during a flight and not actually ignite until some time later.
Because of this, I urge anybody using these LiPo-powered toys to ALWAYS use a Low Voltage Alarm. If you don't know what I'm talking about; this is it:
Unlike readings AFTER the flight, these alarms monitor the voltage UNDER LOAD; which is how you WANT it to be monitoring. A higher load caused by a bad motor drawing too much current can cause damage to your LiPo; the 3.3V limit on these is just 0.3V above what we consider the "Danger zone" where cells get damaged. If you're just flying by timer or "by the seat of your pants", you won't know if the cells are actually being drawn...Continue Reading
Posted by mnemennth |
Jun 17, 2013 @ 03:20 AM | 1,836 Views
So... today was Father's day.
My baby grrl decided to make Daddy an original painting, just for me... I'm so proud. Only thing is... her chosen medium was poop, and her canvas was half the toys in the playroom. And herself, of course.
One emergency bath later, and then I'm washing everything in the playroom with sanitizing wipes... I finally get a chance to clean myself up and make a bite to eat.
"WHUMP! WHUMP! WHUMP!" is the sound the TV in the living room makes when she slaps the screen; she does it whenever Pinky Pie or Mojo Jojo is playing on the Netflix.
"Baby grrl, stop beating on Daddy's TV." The sound stops. I go back to my meal.
"WHUMP! WHUMP! WHUMP!" again a few minutes later... "Baby grrl, I told you..."
"DADDY! Baby sisser POOPY!" my 5-year-old son interrupts me. I wolf down the last couple bites, already knowing what I'm going to find.
And it's worse than I feared... all over the TV, all over her hands, all over her face, even her hair.
Fatherhood. The gift that keeps on giving.
As the likelihood that she had gotten it in her mouth dawned on me, I realized it was time for her to get something she'd never had before... a spanking. This was a behavior that we could not permit her to repeat; I was terrified she would wind up with e Coli poisoning. The TV had nothing to do with it; it's an old projection set, and we keep it because we don't want to get a new one for her to beat on. We hope...Continue Reading
Posted by mnemennth |
Jun 02, 2013 @ 05:34 PM | 1,573 Views
Mini How-To : V913 SwashPlate Reinforcement
After flying my V913 for a while and conversing with fellow forumites, it appears the V913 has a common point of failure which anyone who like to fly aggressively will eventually run into: The swash has a weakness around the base of the inner ball link arms.
Photo Courtesy RCG member cloudysea
While I have yet to personally experience a fail THIS epic, enough of my fellow forumites have that I believe it is a common enough failure to try and find a solution. My personal opinion is that if flown conservatively indoors or outdoors in zero to mild wind, as the designers of this toy helicopter intended, it probably won't be a huge problem. However, people who like to fly fast and zoom around their neighbors are also customers, so their opinions should matter too.
Here you can see the basic design issue we're talking about:
While the outer arms of the swash are nice & hefty, AND reinforced with gussets, the inner ball link arms are molded into some pretty thin material with no reinforcement at all.
So... we need to find a way to strengthen the arms without interfering with their operation. I toyed with the idea of just committing some Epoxy abuse to build up the surrounding area; but experience has taught me that epoxy doesn't bond very well with ABS plastic, and tends to just crack out under this sort of stress.
Eventually I struck upon a simple, cheap solution: Paper Clip & Hot Glue abuse. First,...Continue Reading
Posted by mnemennth |
May 12, 2013 @ 01:16 AM | 4,213 Views
Like many members, I recently bought one of the TX-Ready Axe 100 CP on clearance sale planning to use it with my AnyLink-Hacked JR Module & 9XR TX running ER9x firmware.
Also, like many of you, I had NO idea where to start configuring it. So... I turned to my trusty Companio9x eePe GUI; their current versions have a Template Wizard with a built-in Flybarless Template. Unfortunately, this template does NOT include a Gyro Channel; but I'm getting ahead of myself.
If you load the Default FLYBARLESS template into a memory slot on the editor, you'll have a profile that's 90% there already; only the ELEVATOR and COLLECTIVE (CH11) virtual channels will be backwards.
This is easy enough to fix; go into the MIX tab and edit the ELEVATOR Channel from 100 Weight to -100 to reverse the Virtual Channel, then do the same thing for Virtual Channel 11 (Which is Collective by default). You now have all your Collective, Throttle & Cyclic working correctly, but DANG! NO RUDDER!
This is because the Axe 100 DOES have an input for Gyro, like most Gyro-Equipped Helis. You just need to talk to it.
Go back to Mix Tab, then add a new mix on CH 5. I set the source as PT3 (Pot #3, the leftmost one) and give it 100% weight, NO TRIM. Voila! you now have working rudder, and your Gyro Sensitivity set up on the leftmost Pot.
The default curves give you a flyable machine, with curves easy enough to tailor to your flying style.