Undocumented Vex Tech Scavenger Hunt

[karmanyaahm]

The scavenger hunt thread is very popular, so I thought, why not make an informational version of that?

The rules are simple:
Over the years, @jpearman (and others?) have released details about the internals of Vex technology that are not publicly documented.

Find those and re-post them here.
You must have a link to the original post - then you get a like.
Without the link you will be shamed and flamed!

I’ll start:

@jpearman

Halen reminded me that there had been a request for the signatures that vexos uses to detect objects in the dashboard. They are nothing special and were created using the same tools you have, they are.

vex::vision::signature RED_BALL    = vex::vision::signature (1,  9127, 10643,  9884,  -607,     1,  -302, 6.9, 0);
vex::vision::signature BLUE_CUBE   = vex::vision::signature (2, -3615, -2849, -3232,  7837,  9429,  8634, 3.7, 0);
vex::vision::signature GREEN_CUBE  = vex::vision::signature (3, -6371, -5205, -5788, -3855, -2855, -3354, 3.0, 0);
vex::vision::signature YELLOW_CONE = vex::vision::signature (4,  2159,  3375,  2766, -4481, -4079, -4280, 7.4, 0);

[xTigr]

VEXcode console:

What subset of the ASCII/Unicode character set is supported by the VEX IQ Gen 1 LDC screen?

Slightly off topic but related. VEXcode for V5 has a “console” class we don’t talk about much, this allows you to use the screen as output for printf or std::cout. You need to include another header and create one instance of the console class. For example, #include "vex.h" #include "vex_console.h" #include <iostream> using namespace vex; // define console on V5 screen vex::console Console; int main() { int count = 0; Console.init(); while(1) { std::cout << "Hell…

[7996B]

Gif class made by Jpearman as a demo that can show off “a couple of C API’s that we don’t usually expose that were added to vexos 1.0.5”:

Animated GIF Demo (VEXcode)

Hers’s another demo that can be built with VEXcode. It’s not very well developed and uses a couple of C API’s that we don’t usually expose that were added to vexos 1.0.5. I’ll also explain a couple of more advanced aspects of the setup in another post later, specifically how to allow VEXcode access to more dynamic memory than is available with the default project build scripts. output looks like this. [gifdemo] and uses this animated gif. [world] You can display more than one gif by creat…

in that topic he covers how to change the HEAP size:

Animated GIF Demo (VEXcode)

Looks like I had already bumped the HEAP size up to 8MB for this demo, so 45 second gif I would have thought worked, however, you could try changing this line in mkenv.mk LNK_FLAGS = --defsym _HEAP_SIZE=0x800000 -nostdlib -T "$(TOOLCHAIN)/$(PLATFORM)/lscript.ld" -R "$(TOOLCHAIN)/$(PLATFORM)/stdlib_0.lib" -Map="$(BUILD)/$(PROJECT).map" --gc-section -L"$(TOOLCHAIN)/$(PLATFORM)" ${TOOL_LIB} The _HEAP_SIZE symbol control the size, the default for VEXcode if this is not defined is just 1MB, for thi…

factory calibration for IMU:

Full alignment procedure for Inertial sensor

This procedure calibrates the accelerometers in the Inertial sensor and saves the result in non volatile memory. This procedure needs vexos 1.0.10 or later. Only perform this calibration if your VEX inertial sensor is showing angles for roll and/or pitch that are larger than perhaps 1 or 2 degrees when the inertial sensor is on a flat surface that is known to be level in both axis. Some inertial sensors can show significant error for roll and pitch when placed on a level surface. To check a…

[Sylvie]

i advise people to be careful here…

[karmanyaahm]

V5 Brain Electronics

@jpearman

I know exactly what’s inside

To replicate I guess you could start with the Microzed eval board which was used in V5 prototypes, cost $214 - $318 based on which configuration you choose, then add 22 smart ports, 3wire logic etc. and I would be surprised if it’s even possible to build a DIY V5 for less than $400.

Avnet-microzed

[xTigr]

Optical sensor update rates:

V5 optical sensor refresh rate

The optical sensor will send back data to the the brain every 20mS, however, to make the sensor sensitive enough to light the default integration time is 103mS, that means that normally you will see values change approximately every 100mS. The integration time can be changed in VEXcode as necessary, the relevant APIs are. /** * @brief set sensor integration time */ void integrationTime( double timeMs ); /** * @brief get sensor integration time…

[xTigr]

5.5W Motors:

New Products - December 2022 (5.5W Motors)

I’ll answer some of these, some I would need to lookup details so will skip those. This is not a new motor, it’s been shipping with EXP for several months. The firmware is very similar to the 11W motor (same code base). Nominal 200rpm, as far as V5 vexos is concerned it is similar to an 11W with green cartridge. This is a little complicated. We had to make this motor play nicely with vexos, so as it is seen as a green cartridge motor which is 900 counts/rev. Internally it’s a little diff…

[Dave-TBR]

Vex Electronics Taken Apart:

Pictures of Internals of V5 components

I got some requests to post the pictures I took while disassembling and reassembling my V5 components, so here they are. [DISCLAIMER: Don’t take this as a guide in any way. Don’t do this unless you really know what you are doing and are willing to replace the part you are messing with. For the curious of you (like me), I took pictures so you wouldn’t have to do this.] Let’s start things off with the motor: Front cap removed: [Photo Sep 05, 4 23 00 PM.jpg] Casing separated: [Photo Sep 05, 4…