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Just received the MPX7002 analog sensor with +-20 mb full scale. Just a question on 08M2 readadc10: is it necessary to do a let setadc%00000100 to read the analog voltage of pin C.4 into a word variable? I did it with and without and I do not see any difference. Thanks

Hippy you described perfectly the function. I should rename this thread "analog variometer using xxxx". A variometer is an instrument embarked in a flying object which measure the rate of ascending or descending. It is primarily used on model and real gliders and paraglider to help the pilot to...

Good suggestion AllyCat. Have ordered the +- 20 mb sensor and will experiment. Cheers, Anselmo

Hippy, the suggestion of AllyCat for differential maths is interesting. For what I understand it has to be accepted the fact that at a decrease of pressure (sensor moving up) the MSB will decrease while the LSB may jump to 255. If this is correct the code should take care of this "anomaly" by...

I fully agree on the difficulty to calibrate and stabilize a pinhole nozzle but the idea is simple enough to get a try. I am not familiar with FRV setup; if you give me additional details on its usage I will be grateful. Since the analog output of the sensor in static condition is V+/2, it is...

Hippy and AllyCat, probably I found the simplest solution for a variometer using a MPX7002 sensor (data sheet at https://4donline.ihs.com/images/VipMasterIC/IC/PHGL/PHGL-S-A0003207649/PHGL-S-A0003207649-1.pdf). It is a +- 20 mb gauge pressure sensor with analog output (span is 4.75 V for -20 to...

Thank you Alan. I was considering an analog absolute pressure sensor to build a variometer (see VARIOMETER using GY63/MS5611 barometer on projects forum). The resolution (not accuracy) I was looking for is in the range of .02 hPa. The MS5611 has such resolution but needs some complex code. An...

The supply drain current is zero and all combinations of the 3 pins exhibit in excess of 20 MOhm. One exception: resistance with positive at ground pin and negative on V+ pin shows 1 MOhm. I believe it is the silicon substrate diode. The sensor is dead. I'll not buy a second one because I need...

I tried all combinations among the 3 pins and I always get impedances greater than 200 KOhm. No sign of diodes.

At this time I believe the sensor is faulty because measuring its output with a multimeter with reference either to ground or V+ is always zero. The output resistance is in excess of 20 MOhm. I am going to order a new one. Thanks for your suggestions.

sorry for the auto corrections. Pin 1 has a notch. Attached the datasheet.

The package is the 482A-01. Pin 1 has a Nothomb whilw the corner of the package is Cut at 45 degrees. See the attached photo.

hello there, I just bought a MPX 4115A absolute pressure sensor and to test it I used a very simple code: #Picaxe 08M2 #Terminal 4800 #No_Data do readadc10 c.4,w0 debug pause 500 loop the w0 readings are very erratic and change at each reading. The data sheet does not specify if a resistor...

Your note has been taken. Here the latest version while waiting for the FM transmitter ( I temporarely connected an earphone). #Picaxe 08M2 #Terminal 9600 #No_Data Symbol this = w1 : Symbol this.msb = b3 : Symbol this.lsb = b2 Symbol last = w2 : Symbol last.msb = b5 : Symbol last.lsb = b4...

Hi Hippy, now it works well. I had to trim the pauses and the sound parameters. It responds well for altitude variations of .40 meter/sec with different tone depending on the direction. At present the repetition rate of the tones depends on the pauses. I'll make some attempt to setfreq at m8 to...

In a couple of days I'll receive the FM transmitter and I will be able to experiment the sound information moving up and down 10 m.

I implemented the comparison between averages taken at two different times and it works except...... the led connected to c.4 react correctly while the led connected to output c.0 is almost all time "on". The out c.0 is also the serial out therefore in normal operation is disconnected from the...

Hi Hippy, despite displaying as logged-in, I was absent few days. Have read your posts and tried the code of post #73. Reducing the pause to 100 and watching the terminal I noticed a variation on "avrg" of about 3-4 digits for an altitude change of 80 cm. I attach the data. The variations are...

Last attempt: let's do the average=(average+this)/n and add the last 10 readings of b0 into W0. Hopefully the operation will take less than 500 ms. I'll come back once I complete such code.

Hippy, before I consider your post #73 code, let me express a substantial doubt: when I record the least significant byte (bit 0 to 7) of the output, it swings from 10 to 200 without moving. We can apply any smoothing, average or other tools but it will not be possible to have a meaningful data...