Looking back, this project combines allmost all of the tutorials that I have read in this short period: blinking LED, push button, piezo and LCD display. A useful project for every beginner!
I have made this device for some of my friends who have a hard time admitting how fast alcohol influences their driving abilities.
It will test you on three levels because they all have to do with driving a car safely:
- DECISION time.
- REACTION time
- Resistance to DISTRACTION.
However, driving has to do with making fast decisions as well. So in random order you can get a green or blue light first (or multiples). You should not react to this and hold down the push button until the red light appears.
Finally, on occasions you will hear a short beep in between lights (just for fun). By now you are so tense to do well, that a simple distraction like a beep can and WILL set you off!!
A fun game with your dinner guests upon arrival and confronting upon leaving!
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Signing UpStep 1: What you need
- Arduino microcontroller (I have used an Uno).
- 1 RGB LED (you can use 3 separate ones if you like).
- 4 resistors (220 ohm).
- LCD Display
- Piezo speaker
- Breadboard.
- Push button.
- Wires.
- Ping pong ball (optional).
- Box.









































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One of my ideas would be to rewrite the code (I know the basics of the code) to round everything to the nearest thousandth (reaction time), and then have it go to a corresponding LED.
You suggestion of rounding off will work. However, you need to really think about how to use the LED, maybe in patterns or even Roman numbers. Otherwise you'll need lots of them!
If you can tell + from - and you can (learn to) program, there is no limit.
Thanks much!
There are different types of LEDs and I mixed them along the way. I hoped nowbody would notice the inconsistency, but you did!
In the picture of step 2 (with the breadboard), I used a RGB Led with 6 pins:
You can magnify the picture by clicking on the “i” in the left corner and you’ll see.
Later on I obtained a different LED with 4 pins (instead of 6) and to my own surprise, the system was reversed as well:
This is the Led I have used in the reaction Time Tester. Now I went back to step 2 and changed the schemes (Fritzing) accordingly to this new LED. You can see a picture of this Led in step 4 (7th picture).
Hope this helps, if not just let me know.
- The display says "Hold button to start"
- We press the button and the display goes blank
-When we release the button, one of two things happens:
(1) A reaction time is displayed on the display, or,
(2) There is a beep and the display reads, "Released too soon"
At no time does the LED blink or come on at all.
You can see the picture I uploaded. I checked current with a multi-meter and got these results. On the picture, the lead connecting to Arduino 8 has current as soon as you press the button, and then periodically has current as long as the button is held. The lead connecting to Arduino 6 has current continually. The lead to Arduino 7 has current as soon as the button is pressed, and then has current periodically while the button is held.
As I mentioned, I'm new at this, so am a little baffled. Any help will be much appreciated. Thanks!
How many pins does your push button have? (some types block current when the're pushed, others allow current to flow when pushed). Have you checked this with a multi-meter?
This works great ... please know that you've made my daughter's 6th grade science fair project very cool!
Just one question: if it's the science fair of your daughter, how come Dad is doing all the work? ;-)
We really appreciate your instructable and your following up on our questions!
From my own experience, I now that the flu has a great impact too.
Thanks for your help ... it's very nice of you. We're getting nervous about my daughter's science project, so your help is really appreciated.
I was looking thru old comments and noticed that you said you would send a patch if I made this and published it and reminded you. . Which I did and was wondering if the offer is still good. :)
Thanks
And it looks great!
http://www.instructables.com/id/Reaction-Timer/
It started quite simple with 1 red Led. Then replaced it with a RGB Led and finally added some sound as well.
It corresponds actually quite well with the tutorials I have been reading while learning Arduino (see Intro).
Painting will take most of the time (drying of several layers). Few days.
Building, if you have all the materials, some experience and this I'ble: 2 hours.