Excellent Job on your last video
Excellent Job on your last video convincing that middle school kid. I think he’s a Believer and will stick around for a couple more years of this…
I’m just messing with you
I’m just messing with you kenjones1935. Your results were not bad. Personally, if I was going to test this car in a room like this I would get some thick black rubber foam tape and line the walls and then create an inner wall similar to what your doing with those boxes. This way if the cars momentum is great enough it would just bounce off the inner and outer walls and keep going instead of knocking into boxes that move and so high you can’t even see the car. Your cars low to the ground so the foam tape might be a better guide on both sides than just the bare wall and boxes. Not to mention keeping the walls and your car safe from damage while your fine tuning it. This might take some money but I would go the distance. Also, if I remember I think your setup was designed so they could not see the car and run it autonomously until it’s back in sight right? Keep working on it!
Judging from the video - I have a real problem
I think my problem is peripheral vision (hearing) from the front sensors. As the car sped up I had to increase the frontdanger threshold. Now if the car gets turned a little to the left while running down the straight it ‘sees’ the cardboard and turns left thinking that it is coming to the corner. Solutions?
The simple one is to place the cardboard further away from the side wall.
I could rewrite the code so that hard turning left only is allowed when close to the side wall. Trouble with that is if the car ever got free in a room it would crash straight into walls.
I could add left side SRF05’s. That would make staying in the middle of the lane easier and minimize the effect of peripheral hearing.
What do you all think?
Ken
cool
Wished i got this sort of thing at my school, we just do theory 
what would be very cool, would be having a camera at the front of the car, making it seem like a video game 
A video that pretty much shows my idea.
I have added a third sonar sensor. I placed it on the left side. The car how has sonar in front, on the right and on the left. Adding information from this sensor has given the car much more stability.
http://www.youtube.com/watch?v=KDUWyGh8eIo
What do you think? Is there a market here?
Ken
I say “Go for It!” kenjones1935.
I say “Go for It!” kenjones1935. At the worst you could just scrap everything and shoot for the “Real Hooker”. You see only 3 attempts are made to hook middle school students, with the first two failing to make the cut and the last being a sure shot home.
The order of attempts and the average middle schooler response are as follows:
1. Hooked On Phonics (This always fails)
2. Hooked on R/C Cars (Works in the beginning with interest slowly subsiding over time)
3. Hooked On Drugs (A Sure Winner! Providing both mental and physical stimulation as they explore different planets.You as a supplier feed their addiction and in turn they clean you out. It’s a “Win-Win” situation.)
Gotta be a “Hustler” Ken Jones
Gotta be a “Hustler” Ken Jones cause that’s where the money’s at…
I’m just messing with you
I’m just messing with you Ken Jones. You did good. That extra sensor pulled you through. I was just reminding you uH, of your options just in case you decide to take another road. You know there’s alot of Science, Technology, Engineering and Math in drugs also, so you can’t say it’s completely off the table…Take it easy Sir.
Just remember
Just remember if those kids start to push you, then you be their “Pusher”. OK, checking out now. Peace Jones…
Hello again from autonomous-RC-car-negotiating-a-maze land
Sorry, folks, I’ve been distracted trying to figure out how to “kit” this “educational tool” (toy). The Microchip PICKit2 board only costs $23.99. It has a small surface mount proto area. I do not understand how to make use of it. I need to mount my Zettler relay and my TI sn7407n plus a bunch of mini EMS connectors for the radio, the three SRF05’s the steering servo and the electronic speed control. sssissshhh!
Today I eliminated the need for channel 3 on the radio system. Which is very good cost-wise. Regular Ready to Race hobby cars come with only two channels on their radios. Adding the third is quite expensive. The PIC can know it is inside a maze given input from three proximity sensors. If there is something close to the right and to the left then it must be in a maze. The first run of this new algorithm showed it flawed. The PIC thinks it is out of the maze when it comes to a corner.
Back to the drawing board. Any suggestions?
Ken
Maybe you could have the
Maybe you could have the car:
• Check if the car is inside a maze, if true act normally.
• If sensors indicate the car is not still inside, act as if the car was still inside for a second or so.
• Check the sensors again, if it is indicated that the car is now in a maze, resume normal maze behaviour (it was probably just a corner or misreading). If the car is still detecting that it is not in a maze, then this is probably true, so you can revert to non-maze behaviour.
This maze detection thing is more difficult than I expected
My first attempts at toggling between PIC and Radio control automatically have not gone well. I figured that the PIC could know from the proximity sensors that it was inside the maze. There seems to be too many variables.
If I were to use a light sensor to distinguish, which sensor and at what wave lenght makes sense. Remember I am imagining the cars to be racing - going fast even in the maze. This set up would be in a middle school gymnasium - a basketball court maybe. If I could imagine making a maze out of BIG cardboard boxes with roofs I could use simple light detection. But I don’t see how to make that elaborate a maze. Is there a light detector that does not see ordinary ambient indoor lighting, but does see some kind of special light source? Could I run a string of these light sources the length of the maze? Inversely I could run a string of these light sources outside the maze where the cars would see them.
Thanks for your attention.
Ken
The IR beam is sounds correct.
I’ve been having trouble testing this new feature. First, the car behaves as if there is noise in the SRF05 responses. I have no idea if that is truly the case. The car toggles when I don’t think it should. AND when that happens it takes off on its own. It is way too fast to catch. It dodges all around inside my garage. It sees me as somthing to avoid. A video of just that would be entertaining. When I used channel 3 I had an over ride. Not now. (even as I write I ask myself why not, for testing purposes, reactivate channel 3) Dumbo - of course!
I like the IR beam idea. A beam at the entrance to the maze and a beam at the exit. How do I implement that? Do I purchase a heat lamp? Is that the IR wavelength that the sensors recognize?
Ken
The thermal IR that heat
The thermal IR that heat lamps produce lots of is of quite a long wavelength, down in the lower end of the IR band. IR sensors typically work just below red, in the upper IR range, so you may find that they’re not terribly sensitive to the heat lamps.
If the gym lights are on, or there is plenty of light from windows, I don’t see why a normal LDR wouldn’t work in combination with a covered maze. You could fix the LDR facing up from the bottom of a vertical tube with the walls painted matte black to ensure the LDR only detected light from directly above.
How about a simple photocell to toggle
How’s this sound. Two 100 watt bulbs inside reflectors. One mounted close to the beginning of the maze and the other at the end of the maze. I think I could get a standard photocell to detect the difference between that light intensity and ambient room level. The rule for the PIC would be, "See the light, TOGGLE."
Here’s the spec for the PHILMORE photocell 10807:
“A typical use is for switching on lighting after dark. These are also used in alarm systems, exposure meters, flame detectors, opto-couplers etc. This cell has a dark resistance of 5,000 ohms and 300 ohms in bright light (100 cds. or more)”.
If this technique were used in my car an emergency TOGGLE device would be a powerful flashlight.
What do you think? I have the 10807’s. I think I need to experiment. An old fashioned Triplett multimeter should to the trick.
On the old subject of oscillations. There were oscillations in the motion of the car. They were caused by my not correctly selecting the thresholds on the SRF05 proximity detectors. I felt I solved that.
The idea of a WHILE WEND loop is a good one. I sort of do that already. The PIC triggers the SRF05’s many many times per second. My car continues to do one thing until the three echo pattern changes, then it does something else. If there is a bit of noise in one set of readings, it is smoothed over by the next set coming in a few milliseconds. I do not have an error signal.
Ken
Sounds like a good plan,
Sounds like a good plan, nice and easy to manually debug in the field =)
Two separate batteries has been suggested.
I too initially designed with two battery packs. One for the servos and the other for the electronics. My problem is one of packaging. Getting a cheap kit that fits easily into a HPI Racing Touring Car Ready to Race package is way beyond my expertise. Why the HPI car? That is what I have. Also Ten80 Education
( Which I know as http://www.ten80eduction.com)
specializes in using radio control cars for curriculum and lesson plans supporting STEM in our schools. One of that company’s sponsors is HPI Racing. I hope to get ten80 support. One battery is much easier to mount than two.
I took my car again for a run. It is using the “there is nothing within four feet of me, I must be under radio control” toggling algorithm. I liked the effect. It is important that the room have lots of room. Clearly a gymnasium fits that criteria. Adding the photoresistor system is more than I can deal with at this time.
Two projects are looming. 1. Get help and advice on packaging (surface mount prototyping). 2. Create a video story board then shoot a video showing what I have built, why I built it, how to modify the code and why I think middle school students will jump to learn.
I discovered a neat trick today. The studio has a small push cart with roller skate sized wheels. I put my car on the cart (back end facing me - it has no sonar sensor) and pushed it around the maze. I could easily see the reaction of the car to each position. It made very clear that the problems are speed, momentum and reaction time.
Ken
I would appreciate some suggestions
Please suggest your ideas on competitions that could be implemented with my PIC and/or RC controlled hobby level car. Right now all it does is go through a left turning maze. Programming for both right and left turns is the most obvious extension.
What if I added different sensors and maybe some kind of emitter. I am thinking of a game of tag. Somehow the rest of the cars in the group would need to know which car is “IT”.
What fun could be had with a group of these cars?
Ken
HOw to prototype??
How to prototype??
I have installed a second battery pack – four AA batteries now power the PIC and all the electronics except the radio receiver. The original 7.2 volt NiCad battery now powers only the servo, the electronic speed control and the radio receiver.
The inconsistent behavior in autonomous control may have been because of noise, but then it could be because of slow reaction time relative to speed travel. Not sure yet.
I need suggestions on how to prototype this package. There appears to be shops that offer short run PC cards. PCB-POOL advertises in the SERVO magazine. You all have any preferences?
Ken
Ran much better today
It was consistent. I could direct it to the opening to the cardboard maze. It took off on its own coming down to the maze exit without issue then toggling back to radio control. I could direct it back to the entrance without switching channel 3. All is now as planned. I think the second power source has helped.
Softwarewise the next step is a maze that has both left and right turns.
Ken