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Hello Community Tech's,

I am also currently working on a Back up Beeper for a car application. Where I live in an apartment setting, I am having a problem with other driving their cars wondering what I am doing when they are behind me. I like to back up car in so it’s easy to move forward when I move out. I found a circuit in Encyclopedia Electronics Volume III by McGraw Hill and TAB. Written by Mr. Graff. The circuit uses a 555 timer or a 556 timer. I tried a ST555 Timer only to find out its more static sensitive than a NTE995M. I did find another circuit online that use a different part number than a NTE995M timer, but I was unable to find NTE5405. Here is the link for that circuit. <a> http://www.sentex.ca/~mec1995/circ/backup1.html <a/>. I was hoping someone found out how to make the circuit work. I did some research online and found out it is neither the best designed circuit nor the best circuit to use. I have not found any other additional information on this subject to help me along in my project, but I am finding other technicians having the same problems I am having trying to get the circuit to work. That there are many other circuits using a NTE955M to get the same results with fewer components. Thanks in advance for any input or additional comments to help me get to the resolve of this project. Thanks.

P.S. This is also going into my 1999 Grand Prix I am working on a Digital Voltage Panel Meter and when I am done with both projects. I intend to have pictures of the circuit construction, pcb board schematics and application pictures to show the forum. Thanks again for any help in advance.

All you need to do is wire one of these up to your backup lights.
http://www.jameco.com/webapp/wcs/stores ... _336225_-1
It's a piezo transducer (electronic buzzer).It only draws 5 ma so it wont be a burden on your backup lights. Like anything you choose to use, it'll need to be mounted where it won't get covered with mud, ice, whatever.

Tech1970,

Which circuit are you trying to "make work". The link you posted with the NTE5405 or the 555 circuit from Encyclopedia Electronics?

Steve G.

Thanks for the response Sghioto. I am trying to get the 555 timer circuit to work. I bought a PA external speaker to mount in my rear fender. I do have a 555 timer from NTE555. I just need to know how to make this work. I tried at my parent’s house on a static mat, but the circuit never worked. I also bought ST 556 chips and found out that they where static sensitive. They where loose in the tray at the EPO store, not sealed up like the NTE555. I hope you can help me understand what I did wrong, or give me another idea. I would like a two tone back up beeper. Thanks for any help.

Another reason for the PA external speaker is I have another project that will use the PA system in conjunction with another project.

Since you mention its a PA speaker, it doesn't have a 70 v transformer built into it, does it

???? confused

The link in first post goes to circuit using an SCR; there is no 555 timer IC in it (though the NTE part number for the SCR may be similar to the NTE number for timer IC).

Cheers,

A two tone 556 beeper circuit:



Steve G.

Thanks Steve. This is a much better circuit than the one in the book. Thanks again.

If you are building one so you have a project to build fine. But they sell backup alarms in most auto parts stores or department stores in the automotive section. They are under $15 in most cases and can be had for about $3 on the low end. There is one type that replaces the backup lamp with a different style bulb and includes a beeper. (Plug and Play, no splicing)

Here is one example of a very inexpensive One Wire backup alarm:

http://www.amazon.com/Wolo-Model-BA-52- ... auto_img_b

There is another one that sticks on the reverse light (and I assume uses a battery). When the reverse light is on the thing beeps. Down side is it will beep in bright sunlight:
http://www.amazon.com/Allison-Back-Up-A ... auto_img_a

we used the lamp plug in type on our trucks for the telephone company.. plenty loud.. worked and I can't remember having to replace any.. got them at the local auto parts store

I like the back-up alarms they use in the Philipines. It sounds like a flock of birds chirping instead of that monotonous "beep-beep-beep".

A successful design is one that is functional and is comfortable to listen to for the driver.
for some a tone whose intensity increases as the rear bumper approaches some object.
An IR light and infra red sensor could be used to do this. Or the good ol ultrasonic emmitter/sensor.
The design starts with the operator and how they intuitively listen and respond.
unless you only want to warn others as you back up then just add 12v beeper to the reverse
taillight by means of a relay.

I like the back-up alarms they use in the Philipines. It sounds like a flock of birds chirping instead of that monotonous "beep-beep-beep".

I doubt they even have a vehicle safety code in the phillipines. It seems like anything goes. Ever wonder why you never see Jeepneys in the states. They are not street legal (plus they are reluctant to export what has become a national symbol of a sort). So shiny, its like driving behind a mirror. I have never seen cars so pimped out as the ones in the phillipines, right down to fringe around the windshield.

The sounds that cars make are regulated by the NHTSA (DOT) and are kept consistant so listners know the meaning immedietly. (just imagine that blind guy thinking "what an unusually loud flock of birds that is" as he gets creamed by a dump truck backing up. If you put any old sound, its unlikely, but you could get a fix it ticket. The tone, duration of beep and silence as well as the volume are all regulated

For example
http://www.precosafety.com/files/Docume ... 06341c.pdf

When activated, the Back-Up Alarm produces a tone that is
interrupted at a rate of approximately 80 times per minute with equal on and off times. This alarm conforms to SAE J994 OCT03, sound level Type C