LED safety light

[avalon]

As a new flyer to EP helicopters I have been reading up on the pros and cons of Lipo's. Read about a few people killing them by forgetting to disconnect them after flight, I Got to thinking about this an came up with a cunning plan. Plug an extension lead into the spare channel on your Rx and put a LED on it. Ok so far so good except there is about 5v on the end of the lead, as I have very little knowledge about electronics but new this would blow the LED. I put 2 in series, well that worked now I have a visual reminder to disconnect the battery. Question for any electronics buffs out there what size resistor would I have to use in order to drop the voltage enough to use only 1 LED?

Avalon - Welcome to Helitown. This is a perfect question for Thanh Tran who has developed strop lights and Li po alarm. I knows that he does not have any problem sharing any information on this. He is one of the Tech Support team.

[swatson144]

Not a bad idea but...If you get in the habit of landing and unplugging *BEFORE* Carrying it off etc. You'll never have a problem.

If the heli is just sitting there plugged in it is looking for an oportunity to make like Christine, or Chucky (inanimate objects that come to life and cause mayhem in the movies). With some rx if you power down the TX they just go plane crazy.

It just makes sense to unplug on landing and immidiatly after turn your TX off.

Steve

[avalon]

Sounds good in theory Steve, but us mear mortals do sometimes make a mistake, I like a backup plan.

[thanhTran]

Normal high intensity LED takes about 3.6 volts and 20 mA. Assuming the spare RX port of yours provides 5 volts (which normally is), you can use this formular to get the resistor value: R = (5 - 3.6)/0.02 = 225 ohms. You can use a 240ohm resistor to do the job.


Alternatively, you can use lipo alarm connected parallelly to your ESC. It will detect low battery voltage and will either light off or make some sound. More on that could be found here: http://www.tjtrc.com (Thanks Eddie for the introducution.)

Thanh

[swatson144]

Sounds good in theory Steve, but us mear mortals do sometimes make a mistake, I like a backup plan.

I'm a big screw up! I like safety nets! I'd be all for this one except the major point is turning off a TX with out powering down the heli is just dangerous! Not only to the lipo but everyone around you! Noted your warning lamp may act as a indicator to having left the heli powered up, but it wouldn't help the poor sod who had it go full tilt boogie right at him as soon as you turned the TX off.

Some things can only work one way, this is one. Check your freq and pin it. Double check the synth freq before pinning (if applicable) Power up the tx and wait for it to boot, double check the switches, power up the heli. On landing TH, and unplug the heli, power down the TX. move to a good location and remove the battery (put it in the needs to be charged lot). For me when the pack is removed I put the canopy back on sitting atop the battery holder. I can see there is no pack installed.

I'm not poo pooing your idea. It is unsafe to leave any RC vehicle plugged in after a run. Doing so will get you thrown off of organized fields and events. Car, Heli, Plank etc. Safing the model is the 1st thing you do after a run!!! The model is not safe unless power can not reach the motor in any way.

I'm sorry for the rant but even alluding that you might screw up a basic safety step makes me get on a soap box. I know you don't mean to tell me that you are gonna carry your heli around powered up and that you'd like to check the LED to ensure you aren't going to over discharge while you sleep. I KNOW it would just be a warm fuzzy thing. I respect that.

Plug in just before leaving the ground! Unplug as soon as you touch the ground. The flight ain't over until you unplug. Really you can't mess it up. It's that simple.

Steve

[avalon]

Tranh. Thank you very much for giving me the formula to work out the resistor needed for the LED.

Steve, I understand and respect you being on your soapbox about safety, I have two hobbies and they both are potentially very dangerous. One I no longer participate in but I used to represent Australia in IPSC shooting I was also a range office for the same sport. The other I have participated in the 40 years and that is model aeroplanes. I am also a safety officer and flying instructor for the local club. Sadly due to pressures of work I have not been able to attend the club for the last couple of years. Every Sunday I used to be at the field helping new members set up, test and teach them to fly their latest creations. We had a very strict regime of Tx control, the same as I would imagine a lot of clubs. It involved a plastic key with the Flyers name on and frequency on it, this was hung on the antenna when the Tx was in the pound. There was a board with all frequencies on it and a slot where the key fitted, when you're frequency was clear you placed your key in the appropriate slot and that was yours for the next 15 minutes. Huge signs above the pound were there to remind you to make sure that your Tx was turned off and your key removed. There were constant safety seminars and as a final backup one member was appointed safety officer for the day. Sadly at least once a month we used to find a transmitter still on in the pound. In 20 years of being associated with this club the committee never did find a way to stop human stupidity! We did think about summary execution as this always stops repeat offenders but it does have a negative affect on your membership numbers.

I agree the best way to get people to understand the dangers of this hobby is repeated education. I think we're both probably pushing the same wagon, as I am a visual person the LED works from me as a visual reminder, bearing in mind that my soul flying at the moment is indoors on my own. Just leave you with one final thought David Ogilvy of the advertising agency Ogilvy and Mather once said "Nobody ever went broke under estimating their customers".

Bruce

[swatson144]

Sounds like "nuff said".

Steve

Hi folks,
This is becoming a great safety thread now. It is perfect for a starting thread in the Safety forum so I'd like to move it to the RC Helicopter Safety forum and leave the shadow thread at the old forum so that you all don't get lost. You all are great! Please keep on discussing safety as it is always important to put safety first.

[Ranger]

As a new flyer to EP helicopters I have been reading up on the pros and cons of Lipo's. Read about a few people killing them by forgetting to disconnect them after flight, I Got to thinking about this an came up with a cunning plan. Plug an extension lead into the spare channel on your Rx and put a LED on it. Ok so far so good except there is about 5v on the end of the lead, as I have very little knowledge about electronics but new this would blow the LED. I put 2 in series, well that worked now I have a visual reminder to disconnect the battery. Question for any electronics buffs out there what size resistor would I have to use in order to drop the voltage enough to use only 1 LED?

If you follow this link it will take you to a LED resistance calculator http://led.linear1.org/1led.wiz In the first box type in your power source voltage, then in the second box type in 2.1 and in the third box type in 20 and then it will tell you the resistor that you need (this is assuming you are going to use a standard red LED. Regards, Glen

[avalon]

Glen

Thanks for the link, This site make finding the right resistor easy.

Bruce

[Ranger]

Hi Bruce
no worries, glad to be of service Regards, Glen