555 and 4 IR LEDs
Does anyone have a schematic that will help me make an IR Beacon out of a 555, four IR LEDs, a 5V regulator and a 10 ohm resistor ? I have my BOE-BOT homing in a a pulse made by another BOE but is it a waist of a good Basic stamp for it to just sit there and produce 37500 pulses.
it s mentioned here but I never got the schematic
http://forums.parallax.com/showthread.php?p=605150
it s mentioned here but I never got the schematic
http://forums.parallax.com/showthread.php?p=605150
Comments
users.frii.com/dlc/robotics/projects/botproj.htm
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When the going gets weird, the weird turn pro. -- HST
Do a Google search on 555 astable mode and you should find what you need. Here is a good starting point:
www.uoguelph.ca/~antoon/gadgets/555/555.html
Also try doing a search on "infrared proximity detector", since this is what you are trying to build. Several companies sell kits for robots that do exactly what you need, but they are a bit over-priced I think. All you need is a 555 chip, a couple of resistors and a capacitor.
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- Rick
Special_K -- wasn't there another thread along these lines? If I remember, we also discussed possibility of using detectors that work on a different modulated frequency -- 56khz or so -- they're out there. This would prevent interference from and interference to your beacon. You'd also be taking nice advantage of your 555 since you can't generate 56khz from the stamp.
Oh, another thing I remembered -- here's some code I found that lets you use your Stamp to monitor (and therefore calibrate) the 555 timer output.... you'll need to adjust the constants if you have something other than a BS2. Hook the output of your 555 circuit up to a Stamp pin and run the code.
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When the going gets weird, the weird turn pro. -- HST
I think that Special_K is just looking to create an IR beacon...WITHOUT needing any Stamp control.
If that is the case, then either RDL2004's 555 astable multivibrator or Zoot's siggestion without the addition of any control (i.e. always gated ON) should do the trick.
Or have I missed something, Special_K?
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Truly Understand the Fundamentals and the Path will be so much easier...
Post Edited (Tom Walker) : 9/19/2006 1:10:42 PM GMT
allanlane5 what problems will I have?
Let me tell you what I eventually want to happen.
I want the BOE-BOT to be able to navigate to a spot marked by a IR Beacon. I do not know what I will try to have it do when it gets there... Maybe recharge. I want to have multiple IR Beacons maybe 10 -15 feet apart, And for the BOE-BOT to navigate to one beacon then the other. I figured that each beacon can send a small data bit that can help the BOE-BOT tell which beacon is which.
The first part of this project is a self contained Beacon.. Then a beacon that sends a bit of data like the number 1.
But my point was, your design looks like a Beacon, as well as a Jammer. If you have two of them, how are you going to keep them from jamming each other? And they'll probably jam an IR-Remote, as well as any IR-enabled devices in the same room (TV, DVD player, Cable Box, VCR). As long as your 'beacon's are operating, anyway.
It doesn't have to be a show-stopper, I'm just saying that's one of the possible unintended consequences of your beacon.
But start with single beacon, no data. How about setting up a second timer with a NAND chip. You'd have a 555 generating your IR freq. hooked up to one input of a NAND gate. The other input of the gate would be hooked up to the output of another timer, set on a slow frequency, say, 1ms on/499ms off. The output of the NAND goes to one lead on the IR LED, with resistor & power to the other LED lead. When the second timer switches on, it will pass the IR frequency through to the LED for 1ms. Basically you'll get two 1ms IR pulses every second. 3 cheap chips (or 2 chips if you use a 556) and a few parts and a 9v battery.
You might also think about light shields or light baffles if you are trying to home in on the beacon. That could also prevent remote control interference. If you ever want to see really good *optical* control of IR, check out a Roomba demo at a dept. store.
If you want data, or beacon IDs to be transmitted, I dunno, sounds like a job for an S/X....
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When the going gets weird, the weird turn pro. -- HST
Post Edited (Zoot) : 9/19/2006 6:48:19 PM GMT
FWIW, creating the beacons is probably not going to be the most difficult part of this process...
Keep us updated....
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Truly Understand the Fundamentals and the Path will be so much easier...
If you are using Boe-bot IR LEDs/detectors for obstacle avoidance, those detectors will get triggered by your beacon, methinks.
Use a pot in place of one resistor when you build the timers -- that way you can adjust both the IR freq. to match your detetors and you can use another pot to adjust the timing the bursts themselves.
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When the going gets weird, the weird turn pro. -- HST
well yes I guess you are right IR is IR. maybe I can use the sonar.
I have the 3 Sharp GP2D02 Detectors being checked by sonor on the same sensor mount. maybe when IR homig is on the Sharp GP2D02 can not fire. I will have to test this.
If you are sampling and averaging two or three successive readings on the sharp I think you might get one single reading once in a while, but the effect would get average out very quickly.
Here's a timing grid a PIC guy worked out for IR beacon/data with 3 bits of data --
The page is here: roboflag.carleton.ca/resources/technical/ir_beacon.shtml. The sequencing requires nice timing, and you want the beacons cheap, which is what made me think of the S/X for running the beacon itself.
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When the going gets weird, the weird turn pro. -- HST
Post Edited (Zoot) : 9/19/2006 9:19:29 PM GMT
is this really a jammer too because it did not jam a thing
Okay -- the 555 based 'beacon' MAY be a jammer. The BS2 version could be a jammer if programmed that way -- clearly it isn't right now. BUT, you keep saying you want to build a beacon WITHOUT a BS2 -- which raises the possibility of a jammer.
Thats all I'm saying. Be Careful, This Could Happen. COULD. POSSIBLE. RISK. MIGHT see this IF it happens. If after three attempts I've been unsuccessful at communicating that to you, perhaps after you do it you'll see what I was concerned about.
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