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Re: Air Flow Sensor
Looking at the circuit, set VR2 to its maximum,then adjust VR1 to zero the output, then calibrate R2 back to give an output with the range you want. If needed increase the value of VR2 (but I wouldn't go over 10K). Q3 and VR2 determines how much extra current is injected to...
Re: ADC's?
1)
2.) 4.0/10.5 * 15 (4bits is 0 to 15) -> 0101 (5)
3.) 50kHz has a period of 1/50000 = 20uS. therefore 20 x 1uS samples could be made per cycle. Nyquist requires at least 2 samples per cycle.
4.) None is necessary, but amplification up to 2.5v/0.3v (8.33) will yield better...
can't cover it all!!!
Huge difference internally, Externally they do the same thing.
805x family is more a complex instruction set computer (hundreds of instructions) where the PIC is more reduced instruction set and has about 30 to 90 instructions depending on the PIC.
Both have many...
This idea is used commonly with PCI cards and is known as reflected wave signaling. To get a 3.3V signal a 1.8v signal is sent and a short time later the reflected wave will show up at 3.3 ~ 3.6V, *because the data line is unterminated*.
To avoid ringing use termination resistors, it increases...
A 0Ω resistor is used as a link between two points. Its main reason for being in a resistor package is for automated pick and place assembly lines.
Both Analog ground and Digital ground need to be connected as *close* to the power supply as possible, but *each* analog circuit should run a...
As VVV says puting your 4-20mA across a 250Ω resistor wil give you 1 to 5 V, anything less than say .5V means not connected.
The Digital signal has several solutions depending on whether its a data stream or a digital on/off signal, and whether you wish to add more hardware or software...
Size for size Cu beats Al any day. But weight for weight Al beats Cu. Thats why aerial conductors are Al -usually with a steel core so that it doesn't stretch under its own weight as its very ductile.
Al problem is that it oxidises very quickly, so joints are a big problem. Even the Al-Cu joint...
Use Z to electricaly disconnect the *output* from the bus so another signal can control it ( high impedence)
use X to denote a dont care state on the *input*. ie if a=1, b=0, c=X then y=a.b.c would reduce to y=a.b (we dont care about c)
Re: Air Flow Sensor
It looks like that circuit is generating a wind speed to frequency output.
I'd tap off the output of the first Op Amp. Else I'd go looking for a simpler schematic that generates voltage output directly.
As a plus on this schematic if the sensor is a reasonable distance...
A schmitt trigger takes a slow changing or noisy signal that would create many pulses as it crosses a set logic threshold (ie 1/2 Vcc in CMOS) and cleans it up into a single clean pulse by using hysteresis ( feedback) to create two distinct thresholds to change state.
This means the signal...
Re: Air Flow Sensor
Easiest is to use a couple of transistors, one placed in the Airflow and one shielded to pick up environmental temerature.
This will give a differential voltage due to self heating, that will be directly proportional to square of wind speed. Transistors are *real* cheap...
dspic uart sleep
KST hit the nail on the head with both points.
AVR will be easier because you've used 805x.
The application will determine the better Micro.
Even within the families you will need to match the application and interface requirements to the actual micro. The only thing...
Hi, what PIC?
Some divide extenal osc by 4, some take external osc and multiply it through an internal PLL by 4. but I think the highest clock I've seen on a PIC is 40MHz, so I'm taking an educated guess that your PICs Maximum is 20MHz divided by 4 to give an internal clock of 5MHz.
You may...
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