# Need Help With A Small Project...

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#### rs14smith

##### Member
Hi everyone,

Project Idea:
When I'm driving in my car and someone is on my tail, I want to be able to press a button that will wirelessly send a signal to a portable LCD (placed inside my car, in the corner of my back car window) that will display a message of my choosing (something I programmed it to say).

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What I Need Help With:
I currently already have a Parallax board which I can easily use to program different messages into the LCD.

Where I need help is, creating the transmitter portion of the project. That is, figuring out what components are needed to create a button that when pressed, it will send a digital wireless HI/LO signal to a pin on my Parallax board. Once I figure that out, I know how to do the rest.

Thanks!

#### carbonzit

##### Active Member
What I Need Help With:
I currently already have a Parallax board which I can easily use to program different messages into the LCD.

Where I need help is, creating the transmitter portion of the project. That is, figuring out what components are needed to create a button that when pressed, it will send a digital wireless HI/LO signal to a pin on my Parallax board. Once I figure that out, I know how to do the rest.

Sorry, I can't help here, but I'm curious: it sounds like what you need is sort of the degenerate case (mathematically speaking) of a Bluetooth (or other wireless) link, one that simply sends a signal: "I'm here!". So are there any quick-easy off-the-shelf solutions for this? Like maybe a single chip at each end, one transmitter, one receiver?

Project Idea:
When I'm driving in my car and someone is on my tail, I want to be able to press a button that will wirelessly send a signal to a portable LCD (placed inside my car, in the corner of my back car window) that will display a message of my choosing (something I programmed it to say).

Let me guess: "IF YOU CAN READ THIS, YOU'RE TOO DAMN CLOSE"?

Last edited:

#### rs14smith

##### Member
So are there any quick-easy off-the-shelf solutions for this? Like maybe a single chip at each end, one transmitter, one receiver?

I'm hoping there is, as that will make life a lot easier than having to build one. However, building one should not be too difficult either I would think.

Let me guess: "IF YOU CAN READ THIS, YOU'RE TOO DAMN CLOSE"?

lol something like that!

#### Jaguarjoe

##### Member
Add an ultrasonic distance measuring device to your back bumper. Have it and vehicle speed automatically change messages on your LCD. The LCD can start out with polite comments from far away or at slow speed and progressively become more rude as the danger gets closer or faster. If you had a graphical LCD you could even flip 'em the bird but you might want to be sure your car is fast enough for a quick getaway first

#### rs14smith

##### Member
If you had a graphical LCD you could even flip 'em the bird but you might want to be sure your car is fast enough for a quick getaway first

haha love this!

#### unclejed613

##### Well-Known Member
only one problem i see with this..... the driver behind you wants to see what it says next, and so keeps getting closer and closer until BAM! they get too close...

#### carbonzit

Hey, I think I found something that'll work for you. Check out Micrel's QwikRadio line of ASK/OOK transmitters/receivers. (Yes, I didn't know what that meant either until a few minutes ago: amplitude shift keyed/on-off-keyed.) They're single-chip transmitters and receivers, less than $5 a chip. #### rs14smith ##### Member Hey, I think I found something that'll work for you. Check out Micrel's QwikRadio line of ASK/OOK transmitters/receivers. (Yes, I didn't know what that meant either until a few minutes ago: amplitude shift keyed/on-off-keyed.) They're single-chip transmitters and receivers, less than$5 a chip.

Cool, I'll check it out.

#### rs14smith

##### Member
@carbonzit, if you were going about this project, which transmitter/receiver(model#) would you buy? I see they have several, and I see that most use a range from 0-300ft which is great (more than I need).

#### carbonzit

##### Active Member
@carbonzit, if you were going about this project, which transmitter/receiver(model#) would you buy? I see they have several, and I see that most use a range from 0-300ft which is great (more than I need).

Sorry; as they say, that's a bit above my pay grade.

I'm hoping someone else here has had some experience with these modules, or ones like them. I haven't had a chance to look at all of them (I think there are only about half a dozen or so of each). Also not sure about how exactly to interface them at each end, but it looks like it should be fairly simple.

#### audioguru

##### Well-Known Member
I somebody is driving on my tail too close then I gently press the brake and floor the gas. He sees my brake lights and thinks I am stopping and tries to get out of my path. Last week a full size van was on my tail and when I pressed my brake he nearly rolled his van. I think his tires are flat spotted now.

#### Mickster

##### Well-Known Member
If someone is too close on my tail, I'll let them get past at the earliest opportunity and bother someone else.
If they cause an accident with someone else, you can bet your donkey I'd be a witness for them!

##### Well-Known Member
What I don't get is you will need a means to disable or something at traffic lights.

Just a thought......
Ron

#### carbonzit

##### Active Member
What I don't get is you will need a means to disable or something at traffic lights.

AND it with a non-zero speed-indicating signal? Don't know where that would come from ...

#### shokjok

##### Member
I considered the same thing, with the message changing each time the brake switch was depressed. Mine used an LED array spelling out WHOA!, BACK OFF!, YIKES!!!, and some other specific chosen words. Mine isn't wireless, the distance being short enough to not get interference from outside sources. Legal issues aside, my project never saw the light of day.

#### Jaguarjoe

##### Member
@carbonzit, if you were going about this project, which transmitter/receiver(model#) would you buy? I see they have several, and I see that most use a range from 0-300ft which is great (more than I need).

A lot of guys have good success with this stuff:

Professional RF IC&module, RF Components and Digital Sensor designers and manufacturers - HOPE Microelectronics

I doubt if these things are very expensive. For a lot of info, go over to the Picaxe forum and find a guy called "manuka". He spent a lot of time evaluating these kind of modules and the last I heard, he liked the Hope RF stuff the best. His real name is Stan Swan, he's a Kiwi and publishes a lot of stuff down under.
eBay also has a lot of these modules, some incredibly cheap in price and quality.

#### KeepItSimpleStupid

##### Well-Known Member
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