Digital slotless magnetic system (DSMS)

[mymax1972]

Hi everyone,

Max's here, this is my first post in this forum, just joined. Just few things to introduce myself, 51 y.o., electronic engineer, I love programming and create things with IoT, I am also an avid modeler with 3D printing.

I was used to play with slot cars when I was very young and two years ago I discovered what Wes Raynor created as slotless car. Amazing.
Quite recently I have discovered this forum, very interesting content here, many posts were very useful to design my idea to move to digital.

Let me share my idea and where I am in terms of progress update, any suggestion and/or recommendation are more than welcome

DSMS (Digital slotless magnetic system) is structured around three main unit types: Cars, Controllers and one Central Unit.
Each unit contains an ESP32 microcontroller unit (a sort of tiny processor) able to communicate via a low-level proprietary WiFi protocol (ESP-NOW).
Remote controllers communicate with cars (throttle, direction) and cars communicate with the central unit.

What is different in this design is the way the car is built. Cars are designed in a way that the builtin-in ESP32 microcontroller controls four devices:

1) Front axle ONLY CONNECTED with a servo motor to steer
2) Magnetic cursor to follow the wire underneath the track, connected with a digital encoder to get the steering angle (NOT CONNECTED with the front axle)
3) Rear axle connected to a DC motor
4) IR Receiver to understand where the car is (i.e. pit-lane, start/arrival lane)

The core concept here is having decoupled magnetic cursor (that follows the wire) from the front axle. Front axle is driven by the servo, and servo is driven by the ESP32 microcontroller based on the wire input (thanks to the magnetic encoder) or based on the user input (by the remote controller).
Players can change the line whenever they need, no need to design where change-line is possible.

Other functionality we can get with this approach is simulating tire consumption. If tires are 'virtually' consumed we can simulate that by changing the angle read by the magnetic cursor (i.e. over/under steering), forcing the player to do a pit-stop. Other usual functionalities can be implemented (fuel consumption, engine fails, weather, pace/ghost car, etc) in the central unit.

I have started testing this system, by creating software libraries to guide the servo, read the encoder and joystick, manage communications. Devices are in place and tested, in the following post I will share some pictures. Outcomes are very good, system is really reactive and fast. Next step will be to combine all these devices in a prototype car. After everything works properly I will design a 1:32 chassis to simulate on track

Sorry for this long post, I am more than happy to read your feedback, suggestion or improvement ideas.

These links are some references I am using to design DSMS
ESP32 - the microcontroller => https://www.espressif.com/en/products/socs/esp32
ESP-NOW - the communication protocol => https://www.espressif.com/en/solutions/ ... ns/esp-now
AS5600 - the magnetic encoder => https://www.youtube.com/watch?v=yvrpIYc9Ll8

[NFBrown]

Welcome to the forum, Max. I think you have a good idea for improving Magracing. I never had much luck getting the magnet following the track and the servo to play well together when I tinkered with building a car several years ago. And since I don't really have room for a track I went on to other things. I'll be interested in in your prototypes and how your code chooses which input steers the car.
Nick

[NFBrown]

Max
I came to the conclusion when I tried to make the current system to work that it could use more margin. The range of adjustment between success and failure was just too small. I know many people have it working, I've seen the video. Wes, Kim, and Ned have all build cars that work fine.

I had the idea years ago for a car using the track following magnet to control a sensor rather than moving the steering but didn't know how to do it. I knew that a PLC ( I was thinking Arduino to start) could do a better job of balancing the track wire and the hand controller. The track wire sensor stopped me; I knew of nothing that seemed workable.

You have this project well along. Can you describe it further? What does a magnetic cursor look like? How does it connect to the encoder? I understand If you keep the details to yourself. This concept is an extension of Wes Raynor's patent but may be patentable as well.

I am very interested in whatever detail you can share.

Nick

[kiklo]

Just to clarify.
Nor Wes or anyone else are holding any patents any longer to Magracing.
So feel free to join and develop it further.
But that does not keep you from give credit when apropriate.

[mymax1972]

First of all, thank for your interest in this topic.
Secondly, I am not thinking to patent anything at this stage, so no problem at all to share what I am doing. I would share all my outcome in this forum if you are interested

I am doing some tests and results are very promising.

@NFBrown, the magnetic cursor is very similar to the rest of designs I have seen here, with a tiny difference.
The magnetic cursor has a magnet on one side (to follow the wire), and on the other side where it is pivoted we have another magnet, this time a diametric magnet (North and South are not on opposite faces, see below)

magnet.PNG (107.23 KiB) Viewed 39748 times

In this way when the cursors moves (following the wire) the AMS5600 (magnetic encoder) can understand which angle the cursor is doing and send the appropriate message to the microcontroller.
The only caveat is that the encoder (AMS5600 chip) must be very close to its magnet (max 3mm), so I am waiting for my 3d printer is fixed to print a specific front axle chassis to test it meanwhile I have created something with my lego to keep the enconder close to the magnet

By the way the ESP32 it is like Arduino (much smaller and with embedded WiFi), can be programmed with the Arduino IDE, very easy to do.

Progress status:
1) two ESP32s communicate each other using a mesh library (one acting as remote controller, the other as the car). Done, no lag. This mesh architecture allow each device to be connected with max 20 devices. This means potentially 20 number of cars (each car is connected with just 2 devices, remote controller and central unit, while central unit must be connected with all cars, that's why 20)
2) one ESP32 connected to a joystick sending data to another ESP32 connected to a servo. Done, very reactive.
3) one ESP32 connected to a joystick sending data to another ESP32 connected to a servo and to the magnetic encoder. Done, works as expected. The ESP32 ignores messages from the encoder when a message from joystick is received.

What is missing is to print out a very basic chassis to put ESP32 + Servo + AS5600 + DC motor and see how reactive is when the car is moving fast along the wire..... although I would like to create a more strategic game so speed is important but not so much (I would keep the max speed around 2,5 m/s = circa 300 Km/h at 1:32 scale)

A picture about the test (encoder is into the weird lego structure to test the rotation of the magnetic cursor)

image1 (1).jpeg (90.56 KiB) Viewed 39748 times

[kiklo]

Just a thought.
The dice magnet with 'abnormal' polarity. How about using a normal magnet turned 90 degrees so you get the polaity the way you want ?
Mayby a small square magnet is even better ?

[mymax1972]

@kiklo: Good idea, it is something I can definitely test

[WesR]

Hi all, I am still around but we swapped houses last year with our son and daughter in law so I have lost my large garden room where I had my two magracing tracks. I had however pretty much given up the idea largely due to the problem mentioned I think by Nick of the degree of precision needed with maintaining the gap between the magnet and the wire. As said, this can be achieved but I have to admit to spending many hours filling and sanding the track to achieve reliable racing.
Some form of sensor sounds good. I assumed it would be fixed into the car in something like the present position of the magnet, i.e. just over the front axle but Max's idea is a surprise. So the magnet would still have to follow the wire. There would be less load on the steering magnet as it would not have to turn the wheels so the precise gap between the magnet and wire would perhaps not be quite so important.
I shall follow this with interest!
Best wishes to Ned and Kim and thanks to Kim for continuing with the Forum. Wes

[kiklo]

I have been testing and think it helps : making a deeper magnet arm so the magnet can sit inside, it will keep the magnet from getting too close to the wire. And bevel it slightly.

And yes, also testing with bearing.

IMG_20230427_182203.jpg (66.48 KiB) Viewed 39722 times

[NFBrown]

I gave some thought to a tiny wheel on the steering arm to set the magnet clearance and prevent the the magnet scrubbing the track but I never built one. Maybe just recessing the magnet is just as good. I like the ball bearing.
NIck