Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: mdmedlin on March 21, 2009, 08:32:53 AM
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I am looking into different sensors for my robot, I want to expand the $50 robot a little bit. The sensors that I am looking at take 10-30 VDC or 12-24VDC and I was wondering if I should take my 6V battery pack and run another one in series to get the voltage. Is there any extra precautions I would need? Also on a side note, the Radio Shack where I live put all their 6v 1000 mAh battery packs with chargers on clearance, I got mine for $0.47!!!! Needless to say, I got more than one ;). Thank you in advance for your help.
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I wouldnt recommend stepping the voltage up that much. The higher you put the voltage, the more energy your voltage regulator is going to be wasting. The 5v Vreg takes in the voltage, takes 5v and puts that out through the regulated pin, takes ~1v for itself to operate, and then anything thats left over is dissipated as heat. If you double the voltage, your going to be dissipating 6-8 volts(The 6v battery pack at full charge is more like 7v) as heat. Thats gunna get HOT! Also, look at the datasheets for your MCU and the sensors and make sure that the sensors arnt too powerful for your MCU. If the sensor is ouputting too much power or the wrong kind of signal, youll either fry your MCU or it just wont be able to talk to it.
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A fix to the Vreg problem would be to get a 5v switching regulator. They basically turn the input line on and off repeatedly to give a 5v duty cycle and then smooth it out. I actually have 2 switching regulators in my supply that I think can take a max of 30vdc and they output 5v regulated and theres almost no energy waste! No or low energy waste is good so that your batteries will last longer :) Although these ones are a little more than I need I think. they have like 5 or 6 pins rather than 3.... I havnt actually used them yet....
Hope this helped!
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I was actually thinking if it were possible to have maybe 2 power busses. One for the 5V and another for the ~12V. I could power the sensors with the ~12v and take the output signal and step it down to ~5v if need be
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Hi,
I was actually thinking if it were possible to have maybe 2 power busses. One for the 5V and another for the ~12V. I could power the sensors with the ~12v and take the output signal and step it down to ~5v if need be
Go with just 6V and use a low drop regulator for the 5V and a small step up switcher to get the voltage for the sensor...
OR
Use two serially connected batteries and a somewhat larger step down switcher to power the 5V bus.
Using serially connected batteries and draining from both 6V and 12V will ruin your batteries, since they will be discharged differently.
But... Why not reveal the sensor in question - preferably with a datasheet?
That way it's possible to give the best advice.
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The data sheet for one of the sensors I use is this one: http://www.turck-usa.com/illustrations/S4602740%20(sheet_1).pdf (http://www.turck-usa.com/illustrations/S4602740%20(sheet_1).pdf)
It is an industrial application, I know but I have access to them because I work in an industrial environment. If need be I will just try and find some other sensors to use
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Hi,
As long as you hook them up to a controllers input with a pull up resistor of eg. 10 kOhm, they takes less than 10mA.
Depending on how many you plan to use (I assume they are inductive proximity detectors for ferrous materials?), a single battery and a step up switcher would be my first choice.
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I think its a live wire detector?
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5v to 12v converter:
(http://www.reuk.co.uk/OtherImages/5v-12v-step-up-converter-circuit.jpg)