After near tree months I recived happy the Lidar Lite V2, but now I have a concern because, apparently is discontinued?
something wrong with this thing?
It's a risk to put on my quad? :(
Answer I recived: Lidar was purchased from Garmin, so It's going to re-appear under Garmin name.
Now is in the market Lightware, developing altimeters for Ardu pilot and helping rangefinders users in this forum ( http://www.lightware.co.za/shop/en/4-drone-altimeters. )
I changed the title because this post discussion content look's usefull for other rangefinders too.
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I know Garmin. Garmin is a big name, and you will pay for it.
That's the way it works in America, I have lived in this country for 76 years on Feb 29,2016. and that many years gives you a good understanding of how things work.
But in reality I'll only be 19.
@James tate - so you're a real youngster then ;). I don't normally comment on competitor companies but as a general principle of business you are 100% correct in saying that prices normally go up after the acquisition of a small company by a larger one. My last company was sold to a Fortune 100 monster and it nearly doubled the price of the products. Product development also ground to a halt because of the additional weight of administration and the number of interest groups within the company all trying to put their brilliant ideas into new products.
Do you mind me asking why you want to go >400m? This is of course higher than the legal operating altitude for a drone and wouldn't make sense for terrain following or landing.
Hi Laser Dev, in Australia commercially we can get an area approval for higher alts (date / time, max alt and geographically limited). So it is very easy to fly higher legally here (well outside of towns or cities that is). Also as a hobby flyer here we have no alt limit (must be able to see it) unless we are in controlled airspace, flying near an airport, and a few other possible conditions Not everywhere has a 400ft limit.
In the UAV Challenge that you guys are donating 20 SF/10's for the max operating alt is 1500ft for the comp. My team wont be flying that high but it is an option.
Chris
I choose from here http://copter.ardupilot.com/wiki/common-rangefinder-landingpage/ If not supported by Pixhawk is not usefull for me, If you sell range finders perhaps you can contact dev team to see if possible to include it.
It's ok a 1/4w resistor to plug by pwm?
For your interest, here is how to calculate the power requirements for a resistor:
The resistor power dissipation (P), in other words how much power in Watts is being converted into heat, depends on the resistor value (R) and the amount of current (I) going through it:
P = R x I x I …………………. Eq 1
In many cases, you don't know what the current (I) is but you do know the voltage (V) across the resistor.
You can calculate the current by using the resistor formula that defines what a resistor is for a given voltage (V) and current (I):
R = V / I …………………….. Eq 2
Rearranging the variables, the current(I) for a resistor value (R) and voltage (V) is given by:
I = V / R …………………….. Eq 3
Now that we know the current (I) and the resistor value (R) we can substitute equation 3 into equation 1 as follows:
P = R x V/R x V/R
Which simplifies to:
P = V x V / R...................... Eq 4
So equation 4 tells us that the power (P) dissipated in a resistor is proportional to the square of the applied voltage (V x V) and inversely proportional the the resistor value (R).
Qualitatively, you can say that the resistor gets a lot hotter if you put more voltage across it but gets cooler if you increase the resistor value.
For the case of a pull-up resistor on an signal line, the typical working voltage is either 3.3V or 5V and the typical resistor value is around 1k.
For the case where the operating voltage is 3.3V, the power dissipation in the resistor is:
P = 3.3 x 3.3 / 1000 = 0.011W
For the case where the operating voltage is 5V, the power dissipation in the resistor is:
P = 5 x 5 / 1000 = 0.025W
As a rule of thumb, if you don't want a resistor to get hot, make sure that it is running at less than 50% of its rated power, so in both cases above a 1/4W resistor will remain quite cool.
Many thank's Laser, very instructive.
Cala,
So I found an example of when you should consider a 1/2 watt over a 1/4 watt. See http://electronics.stackexchange.com/questions/172855/when-to-use-a...
I believe the PWM power is quite low and a 1/4 watt should be safe to use. But if you test the resistor and it feel hot to the touch while operating the Lidar you may need to jump up to 1/2 watt resistor. I honestly do not recall the power demands on the PWM pin nor the Lidar Light, but if you are unsure, just use a 1/2 watt and you should be just fine.
Thank's Doug, the resistor is between signal and ground, not power so, I understand in your article, 1/4 is ok if not use v ? I have 1/4 but, perhaps, for safe better to buy 1/2
Here the photo http://copter.ardupilot.com/wiki/common-rangefinder-lidarlite/
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