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-   -   Nude Mamba Monster... (https://www.rc-monster.com/forum/showthread.php?t=11912)

BrianG 05.08.2008 09:47 AM

I would say so. If the "high power" brushed motor hookup method is the same as the MM (where you use all three motor wires as the negative wire, and use the battery positive for the positive wire), it would be good for around 600A!

Since a radio receiver simply sends 1ms-2ms pulses every ~20ms to the servos/ESC, all you have to do is emulate that. I've built a small circuit to test servos using a 555 timer, a couple of small caps, and a few resistors. The caps and resistors set the pulsewidth duty cycle and frequency. Quick and dirty for less than $10. Then, it would be a matter of using a potentiometer in place of a resistor to allow a variable output. The only thing I would be concerned about is throttle "drift" if the pot gets worn/dirty over time. I still have the schematic somewhere if you want it (just have to find it).

Arct1k 05.08.2008 10:13 AM

Or just buy something like this

http://www3.towerhobbies.com/cgi-bin...&I=LXVK79&P=FR

Maciolus 05.08.2008 10:26 AM

I want more of these fans!

5V x 0.19A = 0.95W

5.5V (MMM BEC) x 0.19A = 1.045W

Normal PC 25mm fans have no more than 0.5W

sleebus.jones 05.08.2008 11:25 AM

Quote:

Originally Posted by tc3_racer_001 (Post 170482)
W_N, what is TEC/WB stand for?

I'm gonna go with ThermoElectric Cooler/Water Block.

Not sure why you'd want to? Air cooling is much more efficient in this application.

TEC = power hog. TEC's are great if cooling something below ambient improves performance.
Water block needs water, pump, radiator, which will use more power and add a hell of a lot of weight.

BrianG 05.08.2008 11:28 AM

@Arct1k: Yeah, but building it is more fun. :smile: Seriously, I wonder how hard it would be to use a rotary encoder instead. In an R/C, a little throttle signal "drift" is acceptable to a degree, but not for personal transport (safety). An encoder style adjustment would be more resistant to wear and value drift.

@Maciolus: You are making the assumption that the CC fan has a higher airflow output because of the higher power. It probably does, but there is a point where faster airflow doesn't help as much as you would think. Just getting any active airflow is a HUGE help, but increasing it by just a few cfm's will provide marginal benefit.

I'm gonna wait until Castle releases the ESC/motor combos, and then remove the fan, add a larger heatsink, and remove the top part of the case to allow better passive airflow through the fins.

rcmonkey 05.08.2008 12:18 PM

Quote:

Originally Posted by BrianG (Post 170547)
Since a radio receiver simply sends 1ms-2ms pulses every ~20ms to the servos/ESC, all you have to do is emulate that. I've built a small circuit to test servos using a 555 timer, a couple of small caps, and a few resistors. The caps and resistors set the pulsewidth duty cycle and frequency. Quick and dirty for less than $10. Then, it would be a matter of using a potentiometer in place of a resistor to allow a variable output. The only thing I would be concerned about is throttle "drift" if the pot gets worn/dirty over time. I still have the schematic somewhere if you want it (just have to find it).

Do you have a circuit diagram for this? I seams like a fun thing to do if I was bored sometime:smile:

Thanks

Arct1k 05.08.2008 12:30 PM

http://www.free-circuit-diagrams.com...e-servo-tester

johnrobholmes 05.08.2008 12:40 PM

servo tester plus http://www.electricvehiclesusa.com/p.../th-magura.htm equals perfect

BrianG 05.08.2008 02:06 PM

Quote:

Originally Posted by Arct1k (Post 170576)

The only trouble with that one is it uses a PIC, which you need to program and upload. A little difficult if you don't have the tools to do this.

Arct1k 05.08.2008 02:13 PM

Or http://www.tuug.fi/~isaarine/electronics/servo-test/

BrianG 05.08.2008 02:29 PM

That's better. :smile: It's been a while since I've seen individual logic gates...


These are a few 555/556 timer based circuits I was thinking of:

http://hades.mech.northwestern.edu/w..._Servo_Circuit Although, I'd probably use a 556 timer (dual 555's) for space and convenience...

http://members.tripod.com/Sarconastic/servodriver.html

http://www.seattlerobotics.org/encod...Excerciser.htm

What's_nitro? 05.08.2008 05:53 PM

Quote:

Originally Posted by tc3_racer_001 (Post 170482)
W_N, what is TEC/WB stand for? its sick, looks much better than in those other photos ive seen, cant wait!!

Quote:

Originally Posted by sleebus.jones (Post 170561)
I'm gonna go with ThermoElectric Cooler/Water Block.

Not sure why you'd want to? Air cooling is much more efficient in this application.

TEC = power hog. TEC's are great if cooling something below ambient improves performance.
Water block needs water, pump, radiator, which will use more power and add a hell of a lot of weight.

Correct. It would be more for show than go, I just think TEC's are really cool! You'd only need to run about 50-70W through it to keep it nice and chilly. That kind of power is nothing compared to the power that would go through the ESC at ultra-low temperatures. I only suggested the idea because of the single FET board, which makes it possible.

Pdelcast 05.08.2008 05:55 PM

Quote:

Originally Posted by What's_nitro? (Post 170669)
Correct. It would be more for show than go, I just think TEC's are really cool! You'd only need to run about 50-70W through it to keep it nice and chilly. That kind of power is nothing compared to the power that would go through the ESC at ultra-low temperatures. I only suggested the idea because of the single FET board, which makes it possible.

WE DO NOT recommend attempting to remove the MMM heat sink. It would be difficult to do so without damaging the FETs. (besides, removing the heat sink will void your warranty. )

Patrick

What's_nitro? 05.08.2008 05:57 PM

I see. So it IS thermal epoxy! That would be difficult, and yes it would most likely pull a few FETs off the board! :mdr:

BrianG 05.08.2008 06:18 PM

If it's the same stuff you use on the MM, a few minutes in the freezer makes it quite brittle and easily pops off. :smile:


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