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Electric Stunt => Gettin all AMP'ed up! => Topic started by: andreas johansson on July 09, 2009, 07:18:06 AM

Title: My homebrew timer.
Post by: andreas johansson on July 09, 2009, 07:18:06 AM
Hi guys!

As the ZTron Simple timer was a bit too simple for my use I decided to build my own timer so I could get one that works just as I want it to.

I have finished the first prototype and it seems to work pretty well. The timer works this way:
It has one switch to choose the desired RPM (two RPM settings can be used)
A short depress of the start button and the timer signals (the motor turns a couple of revolutions) that the arming sequence has started. Its now 30 seconds until the motor starts. The motor then runs in the desired flight-time, in my case 5mins and 15 seconds. At the end of the flight time the timer drops the rpm for one second to warn the pilot and ten seconds after that the motor is shut down.

If I press the startbutton for 2 seconds the timer goes into a "test mode" with the flight time limited to two minutes. The timer also lights a LED to show that it is in test mode.

With the first prototype that I use now its not possible to change the flight time or the RPM settings with the timer itself, I have to remove the PIC chip and put it in the programmer to reconfigure the settings. However, I am planning for prototype 2 which will have a software that allow to change those settings at the field without the need of a computer.

Andreas
Title: Re: My homebrew timer.
Post by: Dennis Adamisin on July 10, 2009, 08:14:31 PM
Andreas
Very interesting and CONGRATULATIONS on your efforts  H^^  8)

I am just a mere user of parts so I am always awed by tales of electronic gurus like you who make their own timers or Alan Hahn and his hand-wound motors.

I do not remember - are you using a Castle Phoenix COntroller?  If so then in the Set RPM mode you can store a couple RPM's and select between them using your switches.  I am a little surpised at your flight time.  %:15 seems a little tight - is it working out for you or would 5:30 give you a little more comfort?

I also like your short-flight "test mode".

All in all you have made a pretty impressive unit! 
Title: Re: My homebrew timer.
Post by: andreas johansson on July 11, 2009, 03:18:32 AM
Hi Dennis

Yes, I am using Castle Controllers and I´m using the switch to select the desired RPM, if its windy I use the higher RPM setting.
I have build a new unit now, and to make it smaller I have dropped the LED, instead the motor beeps two times when the arming sequence starts in short run mode. There is also now a connection on the timer board where I can connect my field computer (Asus EEE) to change settings. The unit measures 1"x7/8" so its pretty large and its built on a stripboard. When/if I make a real PCB it will be a smaller unit.

Do you think my flight time is a it short?  ;) Well, I try to relearn how to fly inverted right now = I cant fly the FAI/AMA/Pampa pattern, so the flight time is not critical for me at the moment.

btw, yesterday I ordered a motor and some other stuff for an electric Banshee  ;D

Andreas
Title: Re: My homebrew timer.
Post by: Igor Burger on July 11, 2009, 06:05:29 AM
Dennis, I have flight time set to 5minutes and I fly ~6 laps on end, so I can safely cut 2 laps - means another 10 seconds to 4:50 min  ;D
Title: Re: My homebrew timer.
Post by: Dennis Adamisin on July 11, 2009, 06:10:48 AM
an electric Banshee - Terrific!

My flight schedule takes just a about 5 minutes to finish - assuming I do not do any extra laps or anything.  Thus 5:15 would work - just barely.  I am actually running about 5:45 which is a little longer than it needs to be.  I want to dial it down about 15-20 seconds to save a few electrons....