Society of Robots - Robot Forum
General Misc => Misc => Topic started by: dylouttrim on March 30, 2010, 08:58:20 AM
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I am currently working on a project for my school. It requires me to control a mylar blimp (homemade) with some kind of wireless control except for R/C. This lead me to bluetooth.
My biggest problem is being new to this and i really need help with what to by and how to program it to be controlled. And also the components have to be lightweight.
Can anyone help ? thanks
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http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=67&sipp=1&page=1 (http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=67&sipp=1&page=1)
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and with that what kind of microcontroller would u recommend? by it also needs to lightweight
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Axon would be a good choice. Here is an example of bluetooth controlled lights through the Axon:
http://blog.narobo.com/2008/08/bluetooth-controlled-lights.html (http://blog.narobo.com/2008/08/bluetooth-controlled-lights.html)
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Ok now if i buy this microcontroller would i be able to hook up a regular dc motor to it and control it turning on and off or would i need an hbridge. also for batteries, what would u recommend for the lightest weight because in the past i have used lithum-polymer but i don't believe those would have a high enough voltage and/or amp.
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You will need an h-bridge
Lithium-polymer will have plenty of voltage and amps, you just need to find the right one. What volts and amp-hours are you looking for?
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If you just need to control a DC motor and communicate with bluetooth, the Axon is overkill.
Go with a small (and lightweight) MCU like
http://www.sparkfun.com/commerce/product_info.php?products_id=9218 (http://www.sparkfun.com/commerce/product_info.php?products_id=9218)
and this bluetooth module
http://www.sparkfun.com/commerce/product_info.php?products_id=9358 (http://www.sparkfun.com/commerce/product_info.php?products_id=9358)
If you just need to turn the motor on/off without reverse then a simple transistor is probably enough.
Chelmi.
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ok chemli then with these two parts i hook up, then hook the motor dirctly to it? and if it is possible would i be able to add steering into it. and razor i just want the lightest battery possible that can run all components. the blimp has to go approximatly 20 ft. but i would like to be abe to steer it and it has to run for a max. of 10 mins.
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with these two parts i hook up, then hook the motor dirctly to it?
That is not what Chelmi said! Re-read his post. You can not connect a motor directly to a processor pin.
To pick a battery you need to add up the current draw from each piece (processor, wireless, motor) and multiply the current (Amps) times the number of hours you wish to run (10 min = 0.166hr) times 2 will equal the Amp-Hour capacity of the battery needed.
So lets pick some numbers (yours will be different so look them up in the data sheets or measure yourself) to show an example.
Processor = 20mA
Wireless = 50mA
Motor = 200mA
total = 270ma = 0.27A
times 0.166 hour = 45mA-Hr *2 = 90mA-Hr is the smallest battery needed to run for 10 minutes with the 3 parts listed.
Steering could be done by using a servo to move a rudder behind the propeller.
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ok thanks waltr that explains the battery to me a lot more. srry im only 16 and really new to all of this, so thanks for being patient. now for this i hook the processor to the bluetooth module and then how do i connect the motor. and also the servo can hook dirctly to the MCU chelmi suggested correct?
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I was also just looking and found this MCU with bluetooth built in. it is a bit more $ but would it be simpler or would i still be better off with the 2 sepperate pieces?
http://www.sparkfun.com/commerce/product_info.php?products_id=8255 (http://www.sparkfun.com/commerce/product_info.php?products_id=8255)
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then how do i connect the motor. and also the servo can hook dirctly to the MCU chelmi suggested correct?
I was 16 once and asked lots of questions.
How much current does your motor draw (Amps)?
To just turn the motor on and off a simple transistor will work. Here is a schematic.
A hobby servo's control lead can be directly connected to the output pin of a processor.
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im not positive about how many amps it draws it is only a small motor out of an rc car. and with this if i buy the MCU chemli recomends (Pro Mini) and the bluetooth module what else do i have to buy to be able to prgram it or can i just do it over the bluetooth to my computer? and also i have no idea about the programing of the bord ive been reading up on it and been confused more then once.