Yes, it’s another hybrid idea I have here, but one I am sure others have had and perhaps built. I’m intersted in RC conversion hybrids where the original RC gear is still present to control via radia, but there is a control switch to switch it to autonomous control by a microcontroller. Maybe the switch could be controled by the radio gear.
What vehichles besides the Traxxas E-Maxx would be good for this kind of project? I am thinking around $150.00 or so for the vehicle +/$20.00 or so. Someday I really want to get an E-Maxx or something similar, and there is a lot of good conversion info out there for it.
Well, you could always do the “switch” in software.
If you’re microcontroller has some way of knowing when directions from a remote are sent (and most setups that I’ver seen do) then it would be a simple matter to set up a timer.
Then the bot would just wait until it hasn’t recieved an instruction in a couple miniutes and then proceed upon it’s merry autonomous way.
The robot could all-the-while be “listening” for more instructions from the remote.
Just think of the possibilities…
You’re showing off your new car to a friend.
You stop fiddling with the remote, put it down on the porch railing, and start having a conversation.
Meanwhile, your robot slowly starts sneaking away…
Yes, this could work. If signal disappears, start timer. No signal when timer goes off, robot goes and does its own thing. I don’t know how RC receivers work, so am not sure how to detect the loss of signal/command.
Oh yeah! This would be great for Halloween and April Fools Day for sure. Hmmmm, Candid Camera…
But we are getting ahead of me here. I am trying to find out what vehicles might work for this kind of a project - preferable something not as expensive as the E-Maxx even though I would love to have one.
If you’ve got a reciever, you can use the micro’s ADC to indirectly (through a voltage divider) measure the voltage of the motors.
When it’s > 0, you know your motors are on.
That way, your micro will know how long it’s been since the motors were last told to move.
As far as I can tell, just about any RC car/truck would work.
(I haven’t seen anything in your posts that specefies special needs other than the switch.)
Of interest, there was a post a while ago of an interesting RC snow-car with tank treads that you might want to track down…
I was wondering about checking the actual signal level at the RC receiver. No signal would equal a switch to autonomous mode.
Correct. There are no special needs for the vehicle other than being able to be controlled by a microcontroller as well as RC radio gear. The main requirement is it should be somewhere in price between a RS Hummer and the Traxxas E-Maxx).
I might be able to do this with the RS Hummer, but I want something that has easily replacable and obtainable spare and/or upgrade parts available. This may limit me to the higher end of my price range though, unfortunately.
Hmmm… Snow car with tracks… I will have to see what I can find.
The E-Maxx would be a good platform, but new it costs around $320. If you are moving towards a vehicle capable of manuevering well in the snow, then take a look at the Kyosho Blizzards. kyoshoamerica.com/specialtyvehicles/
Those Blizzards are not much less costly than the E-Maxx. If I am going to end of spending $250.00, I’ll just save a bit more and get an E-Maxx (some good deals on E-Bay). Manuvering through snow is not a requirement.
It will be quite awhile before I start on something like this though, so there is a lot of time to look over various options.
I stumbled onto this Tamiya 1/18 TLT-1 Max Climber Kit. It is about mid-range for me, but workable. I could get all the other parts together it needs gradually. This one might make a good hybrid.
Since getting the RC Hummer I have kind of caught the R/C bug. I would like to have something a bit better anyways. I would not be starting a project like this until my little diff drive robot can do more than just run around not bumping into things.
The hotbodies e-zilla is also a good choice, it comes ready to run for $330.00. Make sure you get a truck big enough to hold all your electronics. A smaller turck like the one I use in my r/c drier project has very limited space.
In my opinion, I think looking for the lost signal would not be the best way to go about this. You might want to have your r/c receiver plug into a MCU. The mcu will then just relay the signals to the servos or ESC’s. When you want to switch to autonomous mode the mcu would look for a specific pulse width on one of your channels (probably dedicated to autonomous/rc operation only - like a switch on some of the r/c transmitters).
So, if the mcu sees this particular pulse in a specific channel then you automatically switch over to autonomous or r/c control. This keeps the controller in constant controll, but the vehicle will decide to use that control or control itself.
I don’t want a really big truck though, and I would not plan on adding too much stuff to it - a microcontroller, of course, and some sensors. I’d tap power off the existing battery supply.
To do this, wouldn’t I have to have the MCU process the signals from the receiver, and then send approprate signals to the servos? That seems like unnecessary work considering the receiver can control the servos directly. The MCU would just have to watch for the secret code signal to tell it when to switch into autonomous mode. Of course then, there would be the possibility of having two conflicting signals sent to the servos at the same time without some switching logic in place.
This would assume that every stock radio set has such an extra switch or control, which may not be the case. Some of the less expensive setups may not have any extra programmable controls.
I can just see my truck spot a cute little sports car and take off running after it, leaving me in its dust…
I’m thinking about this angle of having the microcontroller interpret signals from the R/C receiver and pass on appropriate commands to the servos and such. I’m not sure most of the lighter duty controllers would have the processing power to do all this and other stuff at the same time. Now, a Propeller Chip could handle this and a lot more easily and concurrently.
If you are looking for a small car, the 1/18 scale minis might be pretty good for you. They come RTR and are around the price range you were looking at. Im sure you can find a suitable platform one way or the other.
Yes it would have to process the signals. This is not hard to do in code however, the PPM protocol is pretty easy to work with. But yes i do think you will run into a problem if you have them both trying to control each servo at once.
You really wouldnt need a switch. Any channel on the transmitter could do this, you would just need to make sure that the correct “autonomous” pulse is generated.
have u thought about tanks,they have them from 1/24 to1/5 scale at speeds up to 15mph and still able to climb 40* slopes !! well thats where i,m headed .
about the r/c i,m think they continually send pulses , because when u go out of range they turn around and come back (i,m thinking its just the rudder channel) atleast the airplane receivers do .
i,m thinking i could use 2 channels and the pulsein command on my BS2
and have the r/c overide when needed or wanted and let BS2 run obstacale ovoidence(basicly “ROAMING”) and do a u turn and come back
at loss of sighnal, that would work well for my planes too.
how you could do this with a cheap (i.e nonreplacible ) electronics is beyond me, but you could "gut"and replace the eletrics (more money)
with anything u wanted
ps i,ll let u,all know when i get mine together …just put the mattracks on my boebot so it may take awhile looking at making it wireless and joystick controlled might even bypass the r/c . who knows…
i go where the wind blows,
A tracked vehicle of some sort is on my list of robots I want to eventually build. Right now though, I am interested in the monster truck type of truck, and the TLT Max Climber looks like what I want to go with when I do this conversion. It is not a big truck, so I could pretty easily take it with me where ever I go.
Please do let me know what you do. I have a RS Hummer and got a spare partly messed up one for parts, giving me two full sets of tires and mattracks.
well the mattracks slowed my boebot down to half speed .
and i,m still looking at rf control ,link so many choices .
plug"N"play cost to much and dont have enough range i already have some r/c trans/receivers but i want more range and want to able to program my micro with out having to plug it up.
in the mean time i,m thinking i,ll use 2 channels of my r/c to overide
(turn right and left and foward and backward)and use the other 2 channels to switch subroutines. does this sound feasible ,???
Referencing linuxguy’s original idea for this thread, I am developing a human dexterity telerobotic arm. Since the focus of this project is optimal cost/performance ratio the skeletal structure is all plastic, incorporates water cooling for the servos and uses standard R/C servo and radio/receiver hardware.
Currently I’m using Hitec 5995 TGs for the servos, but they’ve been discontinued. The new 5990s (the “replacement” for the 5995s if you need the 416 oz/in torque) only travel 60 deg. under R/C control. These servos are to be used under computer control and require a wider range of pulse width to get to 180 deg. travel.
So, my question is how can I most cost-effectively operate the 5990s wirelessly from a potentiometer-equipped exoskeleton? Is there a simple circuit that could take the square wave output from an R/C receiver and expand it to what’s needed for the 5990s?
Ultimately, having a computer in the teleoperation loop is a benefit as domestic robots should clearly have an intuitive way for an operator to correct autonomous sequences gone awry or simply to program motions (via telepresence). The question then becomes how to use a PC to scan an exoskeleton’s potentiometers and thereby control (probably using an SSC-32 and bluetooth as described elsewhere) the robotic arm in real-time.
This would be great for Halloween and April Fools Day for sure. Hmmmm, Candid Camera… 