Integration of SRF08 I2C sonar sensor (done)

LuFa · Post by **LuFa** » Sun Mar 18, 2012 10:37 pm

Hey ,

can you tell my how to read 2 of SRF08 ?

i think with this function :


Sonar1 = srf08_ctx.range[0]; // Sonar 1
Sonar2 = srf08_ctx.range[1]; // Sonar 2

is that right ?

Thanks

alexmos · Post by **alexmos** » Tue Mar 20, 2012 7:55 am

I am impressed about functionality of SRF08! Now I think it's price resonable. When you finished implementation to code I will buy one to try

About my code: I have found a big problem in my sonar-baro fusion: if sonar gives wrong altitude (due to noise in power), my copter have tend to go very quickly to infinite altitude

This is because baro is tweaked by sonar and there is no diff control. I am planing to constrain sonar-baro error by 2-meter window. If error goes outside this window - no more trust to sonar and we should completely switch to baro. I will add it to r16 of my branch with many other improvements.

Waldmensch · Post by **Waldmensch** » Tue Mar 20, 2012 8:09 am

You could use a frame which reflects the range of the sensor -
- 26cm to 500cm. Each value outside = wrong
- >50cm while arming = wrong (through that my copter is 15cm over ground in total the sonar delivers wrong, I'm not able to mount it 26cm over ground)

LuFa · Post by **LuFa** » Fri Apr 06, 2012 1:59 pm

can anyone upload the newest 2.0 with the SRF08 code ?

boke · Post by **boke** » Tue May 22, 2012 6:21 pm

Hello i have a SRF08 and a Wiicopter! I did download the new Dev-version but how did this work together? The sonar is blinking but i dont get anything in the GUI. What i have to to? And why do nobody test it? I saw videos from feb. Where it works now its may and nothing?
Please help me!

Andi · Post by **Andi** » Mon Jun 04, 2012 8:13 pm

Hello,
can someone help me
I installed and activated the SRF08 in the DEV20120528.
SRF08= the red LED flashes.
Where can I see in the GUI, if the sensor is working properly?
I do not mean that he does
My System = flyduino Megaboard with Drotek 10DOF Mpu

Andi

Tommie · Post by **Tommie** » Mon Jun 04, 2012 8:19 pm

Look at the debug3 label at the bottom of the screen. It should display the distance between sensor and ground.

Katch · Post by **Katch** » Mon Jun 04, 2012 9:00 pm

Is there a good source for this SRF08 sensor - I can't seem to find any.

I found this sensor though;

http://www.ebay.co.uk/itm/150723212509

Looks to be in spec - think it would work with the same code?

Andi · Post by **Andi** » Mon Jun 04, 2012 9:24 pm

Tommie wrote:Look at the debug3 label at the bottom of the screen. It should display the distance between sensor and ground.

Hi , thx Tommie

ok , he works.

One more question:

How does the sensor, the signal is mixed with the Barosignal or how does it work?
PID setting with ALT for the sonar sensor?

@ Katch

I bought my here

http://www.nodna.de/Produkte/Sensoren/D ... 77f7e75558

Andi

Alexinparis · Post by **Alexinparis** » Mon Jun 04, 2012 9:53 pm

There is currently no code in the dev version to support the sonar output (except for plotting it)
But there is already some code working from alexmos.

Andi · Post by **Andi** » Tue Jun 05, 2012 10:28 pm

oh
when it is planned that this works? Sonar switched with AUX without Baro in a first step that would be great
I can not program. I can only test or something for the project donations

Andi

jgrouse · Post by **jgrouse** » Thu Jun 14, 2012 12:49 am

Hi,

I'm having a tough time reading through the posts where all this is at in the current 20120606 dev code (2.0)? I can see limited references to SonarALT in the code and I can get my SRF02 to show the distance in the debug value in the Config app however that's as far as it made it in the current dev code.

Is there a recent chunk of code someone has working with V2 dev code they can post here so I can test it out?

Thanks,

John

PonyoFS · Post by **PonyoFS** » Fri Jun 29, 2012 3:29 pm

Hi,
Do you know what I2c speed is supported by the srf08 ?

Thanks.
Antony.

Alexinparis · Post by **Alexinparis** » Fri Jun 29, 2012 8:20 pm

PonyoFS wrote:Hi,
Do you know what I2c speed is supported by the srf08 ?

Thanks.
Antony.

400kHz is fine with it

PonyoFS · Post by **PonyoFS** » Thu Jul 12, 2012 12:41 am

Thanks Alex.

Tonight i tested it on a multiwiicopter board (V4r5) with a freeimu 0.43 and a navigatron V2 GPS. Nothing to do, the sonar freezes my sensors. No flashing led on it, and on the GUI, sensors are crazy !
Anyone has a solution?

PonyoFS · Post by **PonyoFS** » Thu Jul 12, 2012 3:58 pm

I have the solution, on the multiwiicopter board V4r5, HV i2c bus is powered by the esc when you have separated power... Sorry. :oops:

But i have another problem, address of the srf08 is fixed on 0xF2 (1 long flash and 9 short flashes) and i don't know why. And nothing happened on the GUI.
Do you have a solution ?

PonyoFS · Post by **PonyoFS** » Sun Jul 29, 2012 4:58 pm

Nobody ?

Raptor · Post by **Raptor** » Sat Jan 05, 2013 10:59 pm

PonyoFS wrote:I have the solution, on the multiwiicopter board V4r5, HV i2c bus is powered by the esc when you have separated power... Sorry.

But i have another problem, address of the srf08 is fixed on 0xF2 (1 long flash and 9 short flashes) and i don't know why. And nothing happened on the GUI.
Do you have a solution ?

I have an answer for you on this question I know its an old post, but i thought if someone else was looking at this sensor and did a search, they might find this.

Any ways mine was fixed on 0xF2 as well. the I2C bus uses only the high 7 bits for the address info, so 0xf2 becomes 0x79. I modified the orgional code defining the default address to 0x79 and the moved address to 0x78 and uploaded. See below/ Once i did that it works like a charm. When i left the second one at 0xf0 i got some large negitive number.

#if !defined(SRF08_DEFAULT_ADDRESS)
#define SRF08_DEFAULT_ADDRESS 0x79 /This was 0x70.
#endif

#if !defined(SRF08_SENSOR_FIRST)
#define SRF08_SENSOR_FIRST 0x78 // the first sensor i2c address (after it has been moved)
#endif

PonyoFS · Post by **PonyoFS** » Mon Jan 07, 2013 5:38 pm

Thanks a lot !!!!!!!!!! :-)

You make me very happy !

This sensor is in a dusty box since my question.

PonyoFS · Post by **PonyoFS** » Mon Jan 14, 2013 10:50 pm

Does anyone still working on this sensor?

mehranpour · Post by **mehranpour** » Sat Feb 16, 2013 11:01 am

can i running altitude holding just with sonar?
without baro?

copterrichie · Post by **copterrichie** » Sat Feb 16, 2013 5:33 pm

mehranpour wrote:can i running altitude holding just with sonar?
without baro?

Only up to 9 feet but more like 6 feet is realistic. However, Sonar is not fully functional in the official release.

farzadsw · Post by **farzadsw** » Thu Mar 28, 2013 10:21 pm

mehranpour wrote:can i running altitude holding just with sonar?
without baro?

Yes you can!

I'm using multiwii 2.2 source code, and I just changed a few lines in code to make altitude holding based on a sonar (SRF08) sensor possible.
First of all, you need to get valid data from sonar sensor (SRF08 or 02). Although 2.1 and 2.2 versions of the code have essential routines for SRFx sensors, There are some small mistakes in original source code, see this:
http://www.multiwii.com/forum/viewtopic.php?f=8&t=3212&start=60#p33293
Also, if your sonar sensor (SRF08) is not working as expected in long ranges, you can tune "Range" and "Gain" values to get a valid data. I limited the measurement range to about 3 meters and lowered the gain to ignore weak echoes, by adding two lines to "Sonar_init()" routine:

Code: Select all

i2c_writeReg(SRF08_SENSOR_FIRST, SRF08_LIGHT_GAIN, 0x45);  delay(50); // range= 3m 
 i2c_writeReg(SRF08_SENSOR_FIRST, SRF08_LIGHT_GAIN, 0x18);  delay(50); // analogue gain

Now you will get valid data. If data is not completely reliable, you cannot use it for altitude hold. By some tuning, both SRF02 and SRF08 sensors will provide you altitude data but compared to SRF02, SRF08 is more robust! for example, my SRF02 sometimes generates random numbers above floors with a carpet on it.
By replacing baro Altitude with sonarAlt in line 284 of IMU library, you will have sonar altitude hold:

Code: Select all

 EstAlt = (EstAlt * 6 + sonarAlt * 2) >> 3;

good luck
Farzad

dronius · Post by **dronius** » Wed May 22, 2013 10:21 am

Hi guys, I was trying to get SRF10 sensor to work with MultiWii 2.2 codebase, but found some issues. Not sure how it was supposed to work at all. Perhaps there were some untested parts that got merged in from original implementation? Or perhaps it's just me being not familiar with MultiWill code.

Anyway, got it to work, the main problem was 7-bit vs 8-bit addressing on I2C. See patch attached, should also work with SRF08 and friends.
Note that SONAR_MULTICAST_PING is commented out, check if your sensor supports that (mine doesn't it seems)

I'm also thinking to play with altitude stabilization whenever sensor signal looks reliable and altitude is <= 3m. Above threshold, it would rely on barometer. Alternative is to have mixed contribution of sonar + barometer data into altitude calculation within certain "band". E.g. <= 2m 100% is taken from sonar, and >= 4m 100% is barometer. Inbetween, it's linear.

What is the process of contributing to MWC mainline?

felixrising · Post by **felixrising** » Wed May 29, 2013 5:27 am

Hi Dronius,

Did you get your patch included? After some discussion over at the 2.3 wishlist http://www.multiwii.com/forum/viewtopic.php?f=7&t=3167&start=40#p36647 regarding patch submission process, I'll draft something up on the wiki.. there is also some documentation about the same in the google code repo here: https://code.google.com/p/multiwii/source/browse/trunk/README.txt

Mazz1 · Post by **Mazz1** » Thu Jul 04, 2013 6:13 am

farzadsw wrote:
mehranpour wrote:can i running altitude holding just with sonar?
without baro?

Yes you can!
I'm using multiwii 2.2 source code, and I just changed a few lines in code to make altitude holding based on a sonar (SRF08) sensor possible.
First of all, you need to get valid data from sonar sensor (SRF08 or 02). Although 2.1 and 2.2 versions of the code have essential routines for SRFx sensors, There are some small mistakes in original source code, see this:
http://www.multiwii.com/forum/viewtopic.php?f=8&t=3212&start=60#p33293
Also, if your sonar sensor (SRF08) is not working as expected in long ranges, you can tune "Range" and "Gain" values to get a valid data. I limited the measurement range to about 3 meters and lowered the gain to ignore weak echoes, by adding two lines to "Sonar_init()" routine:
Code: Select all
i2c_writeReg(SRF08_SENSOR_FIRST, SRF08_LIGHT_GAIN, 0x45);  delay(50); // range= 3m 
 i2c_writeReg(SRF08_SENSOR_FIRST, SRF08_LIGHT_GAIN, 0x18);  delay(50); // analogue gain
Now you will get valid data. If data is not completely reliable, you cannot use it for altitude hold. By some tuning, both SRF02 and SRF08 sensors will provide you altitude data but compared to SRF02, SRF08 is more robust! for example, my SRF02 sometimes generates random numbers above floors with a carpet on it.
By replacing baro Altitude with sonarAlt in line 284 of IMU library, you will have sonar altitude hold:
Code: Select all
 EstAlt = (EstAlt * 6 + sonarAlt * 2) >> 3;
good luck
Farzad

Hello! do you know if i can use this metod with "i2c gps nav" sonar? i have HC-SR04 and i want sonar alt hold.
Sorry about my english, thank you!

PolyGONtrauma · Post by **PolyGONtrauma** » Tue Aug 20, 2013 10:46 am

Since my SRF08 is working accurately in debug-window, I wanted to implement the baro/sonar fusion code mentioned on the first page. Unfortunately, the file "MultiWii-V1_9_alexmos_guru.zip" does not exist any more on the server. Is there any way to get the code?

Pat1300 · Post by **Pat1300** » Tue Sep 17, 2013 1:06 pm

Hi PolyGONtrauma,
Last version of alexmos baro/sonar fusion is avaialbel in MultiWii2_0_alexmos_r23.zip : https://code.google.com/p/multiwii-alexmos/downloads/list
Good luck with the merge !
Patrick

kavehslt · Post by **kavehslt** » Fri Nov 08, 2013 10:37 pm

hi everyone

my sfr08 does not work correctly. i change the address to true one like raptor said before ( i have (1 long flash and 6 short flashes) means EC in hex address and i change it to 0x76)) but i don't see any effect in my multiwii config program raptor said by enabling debug 3 we should see the effect but i don't see any thing and i2c error happen after 15-18 second !!!!!! i really confused because when i used HMC5843 with my srf08 from the beginning the i2c error happen.

Please Help me

i used independent sensors

mpu6050 + hmc5843 + MS561101BA + SRF08
and multiwii 2.2. i test all this ways with MultiWii_dev_2013_10_28_r1604 and i give the same result too.

SOS!!!!!!

kavehslt · Post by **kavehslt** » Sun Nov 10, 2013 11:15 am

HELLO WOULD YOU HELP ME PLZ

stardobas · Post by **stardobas** » Sat Nov 16, 2013 10:52 am

in wultiwii 2.3 I haven't success to upgrade SRF08... I've try but I can't compile stretch for my quadcopter....Please have you a stretch to give me for quadcopter just patched with applied sfr08 holding system? I've try to upgrade but.....no success...

stardobas · Post by **stardobas** » Sat Nov 16, 2013 1:51 pm

I've changed address in sensor stretch and now I see led blinking for ping sending....

NEWSSS:
using this: alt.EstAlt = (alt.EstAlt * 6 + sonarAlt * 2) >> 3;
I get only sonar value on altidute in the gui....and fine...work well....but I want use barometer altitude when go up 2 or 3 metres...
I wrote this:

alt.EstAlt = (alt.EstAlt * 6 + sonarAlt * 2) >> 3; // additional LPF to reduce baro noise (faster by 30 µs)
if (sonarAlt > 1) {
alt.EstAlt = (alt.EstAlt * 6 + BaroAlt * 2) >> 3;
}

but I continue to read only sonar value....never use barometer value....

Please HELPPPPPP!!

Mis · Post by **Mis** » Mon Nov 18, 2013 12:24 am

My idea of SONAR+BARO fusion:

Code: Select all

  #if(SONAR)              // BARO+SONAR Fusion
    if(sonarAlt > 0 && f.SMALL_ANGLES_25) {      // use sonar only if valid sonar data, and with inclinations below 25 degres
      float ratio = (SONAR_BARO_FUSION_HC-sonarAlt)/(SONAR_BARO_FUSION_HC-SONAR_BARO_FUSION_LC);  // baro/sonar ratio
      ratio = constrain(ratio, 0.0f, 0.90f);                // min sonar ratio = 0, max sonar ratio = 0.9
      BaroAlt = BaroAlt * (1.0f-ratio) + sonarAlt * ratio;
    }
  #endif
  alt.EstAlt = (alt.EstAlt * 6 + BaroAlt * 2) >> 3; // additional LPF to reduce baro noise (faster by 30 µs)

Need declaration for one "float scale;" variable at begin of "etEstimatedAttitude" function.
Then on config.h we need two more decalrations:
#define SONAR_BARO_FUSION_LC 100 // bellow 100cm use only sonar
#define SONAR_BARO_FUSION_HC 500 // above 500cm use only baro
That's all. Bettwen 1 and 5m althold use baro+sonar fusion proportional to sonar height (lower -> more sonar usage), below 1m only sonar is used, and above 5m only baro is used.
Additionally sonar is used only if inclination of copter is lower than 25deg, because in higher inclinations reading of sonar can have too high error.

stardobas · Post by **stardobas** » Mon Nov 18, 2013 12:45 am

Wow...I've solve it but I don't considerate the inclination...perfect!!! I will try it!

Crashpilot1000 · Post by **Crashpilot1000** » Fri Nov 22, 2013 11:58 pm

Oh, well what was f** up shit from the beginning to the end. Remember what a sonar can physically do and look at that code - it makes you cry.
That "fusion" is gross sh't. Remember: Sonar gives you RELATIVE distance - never absolute hight. So wait another 2 years until mwii understands that.

weebly · Post by **weebly** » Mon Mar 24, 2014 5:33 pm

I'm using multiwii 2.0. I tried to edit the code as described. But it doesn't work. Can someone please upload the full edited code. Plz plzz...... I need the full code.

bc power · Post by **bc power** » Thu May 08, 2014 10:13 am

Guys I need to connect 4 srf02 modules for obstacle avoiding...please help me...

bc power · Post by **bc power** » Wed Aug 27, 2014 8:18 am

I need an algorithm for srf02 4 modules....help me guys................................

iDaniel · Post by **iDaniel** » Wed Dec 16, 2015 4:01 pm

Hi
i´ve connected an SRF08 Module to my arduino uno. Also i´ve got an GY-521 i2c ACC connected. In the Gui is can see the sonar value aon debug3 and it works quite well,
until i dont turn on my transmitter, wich connected normal (no PPM SUM). Then it shows an i2c error and the sonar doesn´t work...but the ACC ist still working. I turn the transmitter of and the Sonar ist working again...

any ideas?

iDaniel · Post by **iDaniel** » Fri Dec 18, 2015 3:44 pm

Ok i have tested now the same code, same frsky receiver, same sensor but another arduino(pro mini) and GY-88 Sensorboard. I works without i2c errors ... so i don´t know why, because of the other arduino or the sensorboard... but i did not want to use the uno anyway on my copter. So i won´t figure out why anymore