How to: Homemade Radar Screamer for under $20

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Texan

Rollie Reincarnated
Joined
Mar 3, 2009
Messages
699
Reaction score
2
Location
Austin, Texas (Lake Travis)
I installed my Passport 8500 on my FJR but wanted a reliable and loud warning siren that I could hear at highway speeds. I considered an earphone directly connected to the unit, but I like the flexibility to ride with earplugs or my Shure EC3 earphones for music. I also considered the H.A.R.D. LEDs, but it was pricey and I still wanted an audio alert that I could hear regardless of my field of vision. I also considered a Radar Screamer which is available for about $90 and which has good reviews (in fact, I have one on order to compare). In the end, I easily built my own and it works great. I think some of you might be better able to make it look better, so if you do, I am open to mounting suggestions.

Here is the way mine looks from the side. The Piezo speaker is mounted under the Ram-mount plate.

dscn0549.jpg


This is the view from the rider position:

dscn0540.jpg


You only need three parts to make this work. I purchased all the parts from All Electronics.

This is the Painfully Loud Mini Siren

dscn0544.jpg


This is the Solid State Relay

dscn0546.jpg


You will also need an SPST switch - pick any one you like. This switch is necessary to turn off the siren when you are riding in a city (everyone within 50' will hear it go off). This is what mine looks like mounted near the emergency flasher switch.

dscn0541u.jpg


And here is the wiring diagram

dscn0553l.jpg


I mounted the relay in a project box and put it under the seat. Again, others may make this look more professional and you could easily hide it behind the fairing.

dscn0542p.jpg


How loud is it? I measured here at 2' - roughly the distance from the speaker to my helmet. 112dB is painfully loud. You MUST wear hearing protection when you are testing this.

dscn0543.jpg


How does it work? I can absolutely hear this even at unintentionally very fast speeds. The audio behaves like the 8500 audio. When there is one bar on the radar, the speaker sounds a "brap" which is easy to hear. With two bars, "Brap, brap" and so on. After about 4 bars, the siren goes open loop and sounds continuously, which is another reason you need the switch to kill the sound as you pass the LEO at legal speeds.

It's functional, costs under $20 and took me only an hour to install. (okay, maybe 3 hours because I did some debugging, but with this tutorial, you should be able to do it quickly.)

Good luck and safe riding.

 
Very nice job, thanks for the write up.

So i guess with this screamer operational you should be safe to enable the auto mute function on the 8500 :)

 
Very nice job, thanks for the write up.So i guess with this screamer operational you should be safe to enable the auto mute function on the 8500 :)
I tried with and without the automute.

With automute, once the mute goes on (8500 goes to quiet beep mode), the 3V min on the relay is not activated and the screamer stays silent. So, in this case, you better have heard the first few beeps before automute activates. I decided to leave automute off to make sure I did not miss any warnings.

 
Good writeup... we good to go now.. you lead and we all can hear it...

Ride safe... Hamie

 
Great project idea and writeup.

Are you naming this Project Lassie, or calling it Porkie's Ride?

:rolleyes:

 
Just curious why you didn't go with this smaller but equally loud XL MINI PIEZO SIREN unit?
I didn't see that one. I will order one and try it out as well. I've got two other bikes that I need to outfit. I'm going to do a stealth install on my ZX14 so maybe this siren is the right one.

I did try another siren with dual piezo elements, but it was not as loud.

Thanks for the link.

 
I notice in the picture of the RS Sound Meter that you have it set to the db "C" scale... how does that translate to the more commonly used "A" scale as far as perceived loudness is concerned?

Nice write-up, and should be useful to many on the board. Thanks for your efforts!

Don

 
I notice in the picture of the RS Sound Meter that you have it set to the db "C" scale... how does that translate to the more commonly used "A" scale as far as perceived loudness is concerned?
Nice write-up, and should be useful to many on the board. Thanks for your efforts!

Don
Good catch, I usually measure A weighted. I went out and remeasured and got the same 112dB measurement. All the sound is concentrated around 1KHz, so both ratings are the same.

 
i mounted mine and used a cheap headset in the helmet. I simply took the headset apart and mounted only the speakers in my Shoei RF-1000 and it works awesome.

 
Top