Feedback from the controller

I have been musing on this idea for a while, so I thought I would make a post about it and see what you guys think. What I would like to see is a controller with something like programmable vibration motors, or programmable LED indicators, or even an LCD Display to provide feedback to the driver about the current status of the program.

The current solution we have for this is to slap some LED’s onto some extension Cords and put them somewhere on your Robot. But in many competition settings this feedback is barely visible, whether it be through bright stage lights or just someone opening some windows on a sunny day, this solution is definitely flawed.

What this could open up the potential for is things like advanced autonomous selection without bending over the field to use an lcd. Or accurate updates on mechanisms real time without trying to make out if that is running at full speed from 12 feet away. Finally, because it is just an upgrade to the already existing vex controller, it could be slowly moved into change with the older controllers still being used and upgraded over the next few years, because it’s more of a convenience than a game changing thing.

And hey, imagine how cool a controller with an LCD Display and a vibration motor working off of an accelerometer on the Robot would be :smiley:

Only thing is it might be too expensive, the joystick already costs 150 US dollars.

This is a complete rip off. You can get a Xbox or PS4 controller for $60 new, and those have rumble, and native Bluetooth/2.4ghz. The Vex controller doesn’t even have a z-axis trigger. The joysticks don’t click, and the only real unique thing it has is the competition hookup. On top of this, the Vex controller requires 9V, where as every other modern controller only requires 3V.

While not unique, an often forgotten function is the integrated gyro/accelerometer. A good demonstration is in VEX’s armbot video. Not really useful in competition, but it certainly is a feature that would attempt to justify the price. However, I do agree that the controllers are pricey, and clicking joysticks would be incredible, as you could have more functionality without removing your fingers from the joysticks.


Nick H. (8000)

When the controllers came out I figured that the tapped holes in the controller were for a display to mount. I figured it would plug into the programming port since you can use it to talk to a laptop, so a display shouldn’t be that hard.

I’ve never looked but I can’t imagine that the debug info coming back from the robot is that complex.

I’d like to see a multiline display, but would be happy with a handfull of LEDs.

As far as the cost of the controller goes, there isn’t huge manufacture volume in them. I bet if you call VEX and order a million of the controllers they can offer you a major discount.

Yes, I do think the Vex controllers are a bit pricey. I’m not sure if that’s simply less cost-effective manufacturing, expensive materials, or a large profit margin. If Vex were to redesign the joysticks, I would like a display, or at least the ability to have an aftermarket one. A clone of the LCD screen would be fine, although a color display might be useful for Vex U with a camera (if someone wanted to use one).
Actually, the accelerometer in the joystick is useful. This year, we ran out of buttons on the joystick (we only use one), and we have a low battery warning that comes up when the battery is below a certain threshold. To dismiss it, we use the accelerometer and shake the joystick. It actually works great for us.

How did you manage that?

The accelerometer has 2 axes, X and Y. They can be read with vexRT[accelX] and vexRT[accelY]. If the value is over a certain threshold, the warning is dismissed and the LCD resumes normal operation.

No, I meant the battery warning, without some sort of joystick display.

Oh, it goes on the LCD. We have the backlight flash on and off, and the screen displays

(battery level, in volts) // (backup battery level, in volts)

The backlight flashes, so we can see it anywhere on the field. It usually shows up at the beginning of a match, while we are still in the starting tile, so we can actually see the battery level.

This is something I haven’t yet tried doing … probably the brightest light on the robot is the LCD screen :smiley: Only thing I have made with the accelerometers in the controller is a robot drive based on the controller’s orientation. Having a shake to dismiss is a really cool idea :D. Maybe we can start working on some other phone-like gestures with the accelerometers. Of course, if you could display that information on the controller without having to use the LCD on the Robot it would be very handy.

I would assume that the infrastructure is already built into the controller, through things like the programming port or even the interface the accelerometers work through (of which I am completely ignorant :)).

When looking at the pricing of a lot of VEX products I have always just assumed they have been marked up for profit reasons, as Pixeltoast has previously pointed out (couldn’t find the thread), the raspi 0 is a $5 computer while a Vex cortex costs $250.

As @Foster pointed out, the controller looks like it has room for expansion. Maybe we could see an optional feedback module instead of a whole new controller :P.

Edit: While we are on the subject, why have we not seen an LCD on the cortex like Vex IQ and Vex Pro. Or native Bluetooth/Wifi connectivity on the cortex and controller. Or integrated motor encoders preinstalled on new vex Motors… Vex, you need to step up your game :smiley:

Honestly, I prefer having everything separate, rather than pre-installed. If an IME breaks, you just buy a new 2-pack for $15 and replace it. But if it’s built into the motor and not replaced, you need to buy a new motor (more expensive than an IME alone), remove the broken motor (sometimes a huge pain), and install the new one. I would like having even the wires completely separate from everything, and just have the same ports as the ones on the Cortex on the motors. That would solve the problem with motor wires shorting inside or behind the rubber strain relief, and when a motor wire is damaged (insulation stripped, connector broken, etc.), you just unplug and replace it.

I was meaning more like the option to have the motor with included IME when purchasing instead of having to add it separately for the sake of time and convenience, especially for newer teams or teams that don’t want to get some brand new motors, then pull them apart.

And oh yes, please, we have a box dedicated to useless motors due to the wires breaking and shorting at just the wrong place in the cable… Even just a better strain relief would be nice…


A few points. The LCD on the VEXIQ is very nice for picking multiple programs, etc. but it’s pretty worthless once the robot gets more than 4’ away (with the robot on the ground and me standing up, that’s about 4’). I find that I use the RGB lights more as driver display on the little guys. They are a good design, they can be seen in a brighter room.

I agree, I like the two part devices. Most of the time the motor does not need an IME on it and the extra cable management is a pain. This is the other advantage the IQ has, the IME cable is part of the single control cable to the motor/brain. I’ve had very little motor damage on IQ, more than I’d like on EDR. So I’d like to keep them separate. You can also use the IME attach process as a teaching moment, “Hey look at all those small, breakable gears inside here, maybe some engineering on our design rather than brute force would be good.”

Damaged motors – Take the “dead” motors and Frankenstein them back to life to make new working versions. While they are apart a quick swipe with a paint pencil or even spray paint on the outer covers will mark them not for competition. But they will be fine for practice builds, new classes, etc.

As far as $5 Pi’s go, again it’s a matter of scale and what they are. The Pi Zero is a just a circuit board that has sold over 200,000 units already and is planned to sell about 50,000 per month (from RaspPi site). As the volume goes up the cost can go down. Lots and lots of engineering upfront that needs to be paid down during the product life. VEX does not have anywhere near that volume. If they did have that volume we would be up to our elbows in competition teams and a massive stream of roboteers coming out of the schools. While VEX isn’t small quantities, they are not selling millions of controllers or Cortex devices.

You mentioned Bluetooth and WiFi support. All I’ve heard is having the ability to plug the VEXnet dongle into my laptop and have driver software I could call and run the robot from either a controller or the PC. But to be honest you can do that today with two cheap serial transceivers plugged into the serial ports. I did it back in the Pic days with two XBee chips.

Not sure about what “upping the game” wants to imply. I think if you were to head into a small shop and ask them about their supply chain you will find an interesting story. Or reach out to a Kickstarter, you’ll find lots of stories about founders working for pennies an hour. Not viable for a long term company effort.

The good news is we are only 6 weeks away from the famous JVN new product presentation at Worlds. Maybe they have some hot announcements. We’ve asked for lots of items, lets see what we get.