Background: AMS1117 PS regulator SOT-223 Thermal Considerations
The AMS1117 series have internal power and thermal limiting
circuitry designed to protect the device under overload conditions.
However maximum junction temperature ratings of 125°C should
not be exceeded under continuous normal load conditions.
Careful consideration must be given to all sources of thermal
resistance from junction to ambient. For the surface mount
package SOT-223 additional heat sources mounted near the device
must be considered. The heat dissipation capability of the PC
board and its copper traces is used as a heat sink for the device.
The thermal resistance from the junction to the tab for the
AMS1117 is 15°C/W. Thermal resistance from tab to ambient can
be as low as 30°C/W.
The total thermal resistance from junction to ambient can be as
low as 45°C/W. This requires a reasonable sized PC board with at
least on layer of copper to spread the heat across the board and
couple it into the surrounding air.
Experiments have shown that the heat spreading copper layer does
not need to be electrically connected to the tab of the device. The
PC material can be very effective at transmitting heat between the
pad area, attached to the pad of the device, and a ground plane
layer either inside or on the opposite side of the board. Although
the actual thermal resistance of the PC...Continue Reading
Posted by HeliFlyer711 |
Aug 23, 2011 @ 01:23 AM | 4,992 Views
Running on WiFi from an IPod Touch....Nice little quad packed with technology. It's been called a flying computer.......I'd have to agree. It has sonar sensors on the bottom, along with adaptive video camera that tracks the ground up to 20ft to keep the craft locked on course. Theres also a horizontal camera wih a wide angle for FPV if your into that sort of thing. Brushless inrunners on each corner and with the settings turned up it moves pretty fast. Here, in this vid the settings are at about 75% for stability.
Posted by HeliFlyer711 |
Jun 05, 2010 @ 07:10 PM | 7,327 Views
Testing out a new Detrum GY48v Gyro on my Belt, made a little vid & took some pics after dialing it in which went pretty smoothe. For $20.00 its wears well on the belt and flys nice for a piezo.
Much better than the stock gyro IMO.
New head balance - some would call this running up the head.
IMPORTANT : Wear goggles you can lose an eye if a flybar comes loose...ask me how i know this
1) Install main shaft, gear and collar, run and check for true, sometimes the gear can be out of round and you can bend it pretty close to straight, if not it will produce vibes even at speed when it looks straight, this can effect the gyro and consequently the tail, sometimes you get lucky and it is straight out of bag. Also the tail gear has to be aligned properly, and check your gear mesh on the motor pinion is not too tight and not too loose. I keep the collar on the top bearing seated and not loose so there is no play/slop.
2) Install head block only with pin, check for true at speed on shaft, by looking at center dot on head cap... Once verified straight remove.
3) Assemble complete head - install on shaft and eye up linkages, I use a caliper to make them all the same, but due to servo arms being off, those you have to do one at a time, if you look in the center of the swashplate there is a bearing where the shaft goes through, if you get that bearing level on all sides your swash is level. (I usually get 17mm on the flybar guide links, and 5 turns out from closed to start on the bell/hiller mixer arm, which one immediately gets screwed down once i run the head up)