Originally Posted by Joe S.
Why don't people read things fully and properly instead of just seeing the bits they want?
In the order highlighted (and not highlited) above...
GPS Speed accuracy:
speed measurement with accuracy approaching 0.01 knot (Knot is used by GPS satellites and has top be converted to MPH or KPH) is possible by using GPS Doppler data.
Way too complex to explain how the speed is calculated here in a few lines, but If you want to read up about it I suggest you start here http://nujournal.net/HighAccuracySpeed.pdf
HOW did you measure your speed?
and how did you work out your sat nav was 5mph out?
this is actually impossible once it has a lock on 3 or more satellites, again read the above article.
Also i suggest if your still not sure then have your sat nav compared against a police calibrated speedometer, or laser gun, they are calibrated.
Yes I am allowed to use GPS for speed, nothing in the rulebook says I cant, and besides If you had seen what I said earlier, I have a speedometer in the car already, the GSP speed will just be a backup so I can see A: my "REAL speed" and B: have a warning if I go over a preset limit (which I set in the program)
The GPS unit I will be using will be able to calculate data at a frequency rate of between 1 and 5hz, depending on how I program it.
Most standard "off the shelf" gps units output data at 1Hz.
The GPS will only be SENDING DATA to the pic, the pic will NOT be talking to the gps unit once it's set up.
As to update speed, on a bynote:
ALL the calculations regarding converting gps data to speed is already done in the GPS unit, the ONLY thing the pic will be doing in regard to that, is taking a serial output from the gps, looking for a certain data sentence, and just displaying the speed on a 7 segement display.
No major calculations in the pic, other than converting knots to MPH.
The DS1820? I dont see the relevance as it's only going to be measuring the outside temperature from behind the front bumper of the car and does not need to be highly accurate or update often.
Controlling Solenoids:
I dont see a problem at all with this, all I'm going to be doing is sending either 1 or 2 ports high (switching the solenoid) once a certain state has been reached, and they will STAY high untill I finish my journey or decide to turn them off before that.
There is no high speed switching, its only on once and thats it.
Turbo? it wont be going anywhere near the turbo at all, it was never mentioned.
I asked what to me seemed to be a simple question because I'm new to programming Pic's, in fact I only got the development board working this week, now to you "experts" it may have seemed a stupid question, but like I said in the beginning of this post, I just wanted a straight answer .. can it be done or do I need 2 pics.
Oh and for those that didn't see it earlier, i want to use GPS because of the accuracy, IF I was to use a sensor connected to the driveshaft or anything it's never going to be as accurate, and would need a mechanic to fit it and so on, the gps option I can program myself, so no other people needed to work on my car.
btw whats wrong with blondes working under car hoods?
Women can do almost anything these days, this isnt 1960 anymore.
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