SparkFun Electronics Forum

Greenlight wrote:I think at 90 seconds the average speed would be about 6.5 mph
Shimniok, It looks like from your video you will have no trouble beating that speed.

True... my robot will be a little faster than that... in the wrong direction

Also, crashing into things lowers the robot's average speed somewhat...

I had some setbacks the last week or so but I think I'm almost caught up to where I was two weeks ago. Which was about a month behind.

Seriously tho, I am making progress, especially the last few nights. The main challenge right now is getting good gyro and compass readings.

I think the robot can navigate on GPS alone, worst case. Hopefully I can sort out the issues or else I will ditch my 3DOF poor man's IMU in favor of a more polished, COTS solution. I prefer system integration to in-the-weeds development when affordable

And, I hope to have the obstacle avoidance stuff in a barely-working state by the end of the weekend.

Cripes, just over 3 weeks left. That's like a splash of cold water in the face... ok, back to work...

Michael

I am having ping sensor issues. I have up'd the speed to about 12 mph and the ping sensor in front really isnt seeing much. Im not sure if i just dont have enough time to respond to a detection, or if it may be due to doppler effect. At 12 mph the detected frequency is changed by the doppler effect by 3 percent. Im wondering if that change in freq is making the echo undetectable. I believe the frequency of the echo will be about 41230 at 12 mph. Does anyone know what the maximum frequency the ping sensors will detect before they stop working all together? Or does anyone know who i should pose this question to?

If the ping is unusable i guess ill have to go blind. It has made it around the building blind before, but its kinda iffy. I guess we get 3 tries though right?

ok i finnaly got a video up of one of our earlier test runs...before we up'd the speed.

http://www.youtube.com/watch?v=muhY8RTKlbc

Video from test run today

http://jessejay356.blogspot.com/2011/03 ... ntrol.html

Wow, those videos looks great!

I have no idea what the ping sensor's freq response range is but you might post over on parallax forums... one of the Parallax employees may be able to chime in. Surely the response range is more than ±3% ... but... ?

Doppler effect. That's yet another detail I never considered. I'm using a different sonar, but the question still stands. I've yet to test my object detection sensors on the vehicle at speed. Very soon...

Likewise, I'm also close to testing numerous recent nav improvements...

Thanks for posting the vids, that really helps motivate me to get my butt in gear

For some reason that last video looks a bit faster than 12mph

I'll be updating my blog over the next two weeks with progress on my AVC2011 entry. I'm re-entering Tobor from last year with a much better obstacle avoidance system (my weak link last year). Last years obstacle avoidance was rigged up and tested in a hotel room while I was out of town at a conference the week before the AVC. I'm hoping to do a better job this time around. I'll be fusing the data from three IR range sensors and five ultrasonic sensors.

http://scottrharris.blogspot.com/2011/0 ... dance.html

Since everyone else is doing it:

New semi-interesting video on my build blog: http://stkwans.blogspot.com/2011/04/thi ... -work.html . This one is from the onboard camera. Once I get the image processing system squished down small enough to fit in an LPC2148, I can do obstacle avoidance with it . Actually, it's just a passenger.

The whole reason I started with a helicopter is that I didn't see any at the last AVC, and I actually thought it would be easier than a car. Obstacle avoidance would be easier, all the bonuses were for aircraft, and cars have been done to death.

@trialex: arg. you probably know how these things go. I'm still planning on bringing something (at the very least: myself) to the competition, but it means a very busy week. Flying's harder than one would think.

Well guys, I'm out of the competition for this year. I lost my HMC5843, and even then my code is just not up to snuff yet. I will continue to work on my vehicle till it is ready. If I cannot do 30 mph, I will be not be happy. Countdown to my AVC entry... aprox 370 days.

jessejay356 wrote:Well guys, I'm out of the competition for this year. I lost my HMC5843, and even then my code is just not up to snuff yet. I will continue to work on my vehicle till it is ready. If I cannot do 30 mph, I will be not be happy. Countdown to my AVC entry... aprox 370 days.

You mean i crashed into the concrete 20+ times for nothing? I was trying to up the speeds to give you some competition. Your video scared me into thinking i needed full speed around the track to win. I didnt make it to full speed(25mph) over the weekend, but i got pretty close(about 20mph). I still dont have any obstical detection though.

I promise you, I did you one better. I crashed into a full size truck at 30+ mph, and snapped the nylon bolts holding my compass on. I didn't notice it right away, and it got ran over. The board was there, but the module was gone! *sigh* I promise to be at 30 MPH next year, or I will be in the LAKE! I'm switching from a 2WD brushless vehicle to 4WD brushless. I have so much power, it will do wheelies like no other!

Hopefully, your speed will get you a win this year!

Jesse

Greenlight wrote:

jessejay356 wrote:Well guys, I'm out of the competition for this year. I lost my HMC5843, and even then my code is just not up to snuff yet. I will continue to work on my vehicle till it is ready. If I cannot do 30 mph, I will be not be happy. Countdown to my AVC entry... aprox 370 days.

You mean i crashed into the concrete 20+ times for nothing? I was trying to up the speeds to give you some competition. Your video scared me into thinking i needed full speed around the track to win. I didnt make it to full speed(25mph) over the weekend, but i got pretty close(about 20mph). I still dont have any obstical detection though.

I was at SFE HQ Sunday afternoon and nothing was working. I even had some magic smoke coming from a Maxbotic sonar module for no apparent reason. I took some data and I'll be fine tuning my obstacle avoidance and waypoints.

I couldn't even make it around the building.

ScottH wrote:I was at SFE HQ Sunday afternoon and nothing was working. I even had some magic smoke coming from a Maxbotic sonar module for no apparent reason. I took some data and I'll be fine tuning my obstacle avoidance and waypoints.

I couldn't even make it around the building.

I'm jealous of you Colorado guys. Being in Iowa, it's a lot harder for me to test under competition conditions. It's a 12 hour drive just to get to Sparkfun. And flying seems out of the question, all those wires etc probably won't make me very popular at the airport!

Last year I took my AVC entry on a plane as carry on so I could work on it while I was at a conference in CA. The TSA was very interested and wanted to see the car after it went through the X-ray machine, but it only added about 10 minutes on each end of the trip. The TSA folks in Denver were pretty excited about the AVC. Not sure if any of them showed up, but I told them to come spectate.

Tell the TSA you've got a robot and give them the nickel tour. It's legal to fly with a robot, so do it! Pack the tools, and hand carry the precious, fragile bot!

-Scott

jessejay356 wrote:
I'm jealous of you Colorado guys. Being in Iowa, it's a lot harder for me to test under competition conditions. It's a 12 hour drive just to get to Sparkfun. And flying seems out of the question, all those wires etc probably won't make me very popular at the airport!

I'm having some rough times myself. Once again my code started hanging for no apparent reason... so that was about 4 hours lost ... instead of working on actual functionality.

I've not tested at SFE yet. I guess I will 'test' on race day

I have some new hypotheses explaining why my compass and AHRS (gyro+accel) are sucking so badly. If I'm right... I probably can't do anything about it anyway because there's no time.

Miraculously the CMUcam1-based vision system that I threw together in a few fast-paced hours seems to work fairly well.

Anti-miraculously, after going through all the trouble to put it together (fabbing an aluminum mount and a custom Arduino-based Serial-to-I2C PCB, writing software and everything), whenever the boards are on, my GPS satellite signals drop by about 30-40db. From tracking 7-9 sats in the basement to tracking 2 or 3. Poorly. I think the two boards are spitting out a ton of RF interference.

So I guess it is back to sonar. Because my IR sensors just don't seem to work reliably.

Well, hey, at least the robot's body is painted.

I am hoping for a great deal of luck at this point.