Firstly, hello to everyone. I haven't been here in a while, but when I'm jammed up I come here for help.

I'm not sure which forum this belongs in......

I promote a speedway motorcycle racing facility and we would like to have a radar speed sign at the end of the front straight so our patrons can know how fast the bikes are moving.

Rather buy a unit fully assembled I was wondering if there is a radar speed detector / processor with two seven pin outs that could be connected relays to fire up a do it yourself LED display.

MOD EDIT: Link removed.

Thank you

 

the commercial grade products seem to be $2-8k
not sure of availability of such sensors, specially in small volume. they seem to be all using K-ban radar. but... that is not the only way to measure speed. maybe the simplest solution is to just use pair of optical beam-through sensors. once you get the triggers it is easy to scale the result and drive LED display. the other would be to have a camera and do some processing with OpenCVetc. not sure what approach is appealing to you.

one can also try to get them from China... $300-400
https://noble2008.en.made-in-china....r.html?pv_id=1i72ehshuadd&faw_id=1i72ehvf0b8d

 

Welcome to AAC.

Your problem is a practical one and easy to solve but your proposed solution tries to make things easier while actually complicating them. You will not find what you are looking for in terms of an almost ready made solution—only complete devices and the parts to build them.

But, you could build something relatively easily and cheaply if you don't try to pre-determine the pieces involved. Thanks for a technology that is not really new but has become practical only recently, a module that will report the distance, speed, and angle of travel of vehicles up to 100m away is available for about $8.00USD, shipped from AliExpress.

The module is the Hi-Link LD2451 [manual] which operates at 24GHz using FMCW mode with a 1T2R (1 Transmit, 2 Receive) configuration. I won't get into the details of what that means, suffice it to say that this module combines the use of a special modulation technique with very smart firmware and freely available configuration software that runs on Android or iOS to create an amazingly capable and affordable to create the "brain" of a complete vehicle RADAR (in the true sense) system. The also offers a version for the detection of people in a similar way.

The configuration software is only needed once*, to configure how the detection will work and what the module will output. But once configured the module will communicate what is sees over UART (serial) (or BT) or can use GPIO for a simple alarm if that's appropriate.
*this is the easiest way to use configure the module but direct configuration over the wired serial connection is possible.

Combining this module with even the simplest of MCUs (microcontrollers) and the display of your choice would result in a cheap and cheerful RADAR speed sign. The hardest part of this project would be the LED sign and weatherproof housings. Combining a 7-segment driver module like this one with something like MOSFETs for current handling, a DIY shadow box, and a set of high output LEDs would make for a relatively easy display.

Of course "easy" is relative—very relative—to your existing knowledge and skills, and how easily you can add to them. But for someone relatively well versed in general electronics, embedded processors (e.g.: "Arduino") and fabrication you are looking at a project that should cost about 20% of the cost of a ready made appliance, or even less.

Using this module and a bit more computing it would even be possible to show cars on a video display tagged with their current speed and probably some other very clever things that don't come immediately to mind.

 

@Ya’akov , your link to the manual seems to be broken.

 

@Ya’akov , your link to the manual seems to be broken.

Thanks. Somehow it dropped the attachment. I fixed it.

 

Thank you all very much, the info you provided is just what I was looking for.

I came here a few years back looking for information on LED displays and this board gave me a great education. I learned about LED types, bead and COB, and I learned how to match drivers, and I learned about heat sink requirements. I am thankful and I might soon put the knowledge to a further test as I attempt to build this device. The physical construction of the LED display should not be a problem as I have an extensive background in fabrication, undoubtedly I will need to learn more about wiring the system and actually getting it to operate, but you folks have me off to another great start.

A special thanks to Ya'akov for the added detail in the reply.

 

Interesting quest indeed!! I enjoy watching the dragsters on the NHRA channel of my recently acquired smart TV. And I have observed that those videos only show Elapsed time and calculated speed.
A "real time" speed display will certainly be unique, and quite n addition. And it will be a bit of a challenge.

So my suggestion is a different approach, which is to see if you can obtain some USED and "removed from service" radar speed meters. Many police departments have all of their installation and repairs done by outside service organizations, and possibly such an organization may be able to provide such speed meters that have become obsolete or inadequate for some reason. Used equipment could be a great source of systems that are already able to do what you need.

The challenge with providing a speed display while the race is in progress is unique in that reporting the variable while it is changing will demand some small delay so that folks can read it.

It was not totally clear to me if this is drag racing or closed track racing. the other challenge will be separating the signals from the different racers, if that is needed. Showing the speed of "the pack" would not be quite as much of a challenge.

 

the other challenge will be separating the signals from the different racers, if that is needed. Showing the speed of "the pack" would not be quite as much of a challenge.

One of the features of the module that I suggested it the ability to provide data on multiple targets. It’s much more sophisticated than a police RADAR gun, particularly an older one.

 

OK, certainly your suggestion will be a far more capable package. If it is done right, though, recycling is rewarding and sometimes a lot cheaper.

 

Speedway Racing is regarded as the original extreme sport and crowds of over 100,000 have attended
events in Europe! It has been called the second largest spectator sport in Europe for years, second only
to soccer! The machines are highly specialized as they are fueled by methanol , weigh just 175 pounds
with over 80 horsepower and have a power to weight ratio similar to a Formula 1 car! They can
accelerate from 0 to 60 mph in less than 3 seconds, have no gears, no brakes and are made to slide
totally sideways through the corners of the dirt oval bullring track!

 

OK, so now it is clear that many of the speed measuring schemes for drag racing are not applicable at all. That leaves LIDAR, RADAR, and possibly SONAR as primary choices, although there are video schemes that also could possibly work.
The suggestion from "Y" may be the best choice. After that there is the question of what sort of display will work best. THAT is a separate issue. The big deal part will be the display update rate.