Let's Make Robots!

Free Range Robots (IR Beacon) **UPDATED**

**Update 4.14.09***

OK, when you watch the video... 

First of all, it is like, 5 minutes -sorry. There is a point though promise, and that point starts at about 3:40 or so. Now, I can't stress enough, the code is wicked chunky as it was written in about 10 min. It is all "bang-bang" and not proportional at all. The final code should be about 10x faster, much more accurate with a lot less trial and error. For now, this is just proof of concept and indeed it has been proven. 


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Chris wrote elsewhere


I started to do some math. $4 for a 08m, $.08 per IR led (needing 3-5 per "beacon"), $1 AA battery holder, some scrap PCB. I'm looking at about 7 bucks per "beacon". With 2 per room (each set to a different output code number) you are looking at $15 or so. --With 2 in each room you can allow for some pretty good triangulation. Even if you add another couple IR led's and a IR transistor, you would still only be up to about $20 bucks a room and with the extra LED and sensor, you could set a beam at the doorway to trigger the beacons to come on for 5 min's or so. The rest of the time, they sleep -batteries would last a long time.


I'm wondering why spend $4 on a micro controller. I admit, I do not know the design of the individual beacon. It's the multiplication of low costs that would drive me insane.

Awakening the beacon from sleep mode: nice touch. But do you really want Bondo to set them off? Or the kids, or anyone else? With a more sophisticated design (not necessarily more expensive) you could have Walter send a trigger. Maybe a flash of IR.

Talking rooms: If the rooms are gonna talk to Walter, why not let them say directly which room they are? IR could easily encode an 8bit message. Or os this the whole purpose of the 08M?


Hi rik, what's $4 for a 08m? - if your trying to do a specific frequency ID for a beacon could'nt you just use a ne556 and a couple caps and a resistor ($0.55). Since you can use both timers - it can be outputing 2 frequencies simultaneously.

in the previous thread.

The $4 needs multuplying by 2 and the number of rooms, in Chris' plans. The lower the unit cost, the higher the multiplier can go within the same budget.

i like the idea of a beacons more -

2 different beacons at the opposite ends of a room on different frequency could ID the room,

but (even better) - if you find the Heading (as CTC has done) on both beacons - do a little Trig. and Viola !  You know the ~exact position of Walter within the room !

it might take 2 readings & encoder output of relative position - but then you could derive absolute position - then Walter can start drawing a map - you could post it - then we all could see CTC's floor plan of his house

Nifty - I like it

What are you using for components CTC, so I can blatantly copy you :)

cool ! is there a page explaning how to make a beacon , transmitter or reciver?

Yeah rik,

Using the IRIN command, you have 128 available codes that can be spit-out and read. Each beacon would have it's own "frequency" and there would be 2 per room again, each having its own code number. With a beacon in each corner, walter could center himself between the two, be a given distance back from them (from the triangulation), know which one is on the left and right and know what room he is in. Using these beacons in a few stratigic locations, and an eeprom table of distances to and from other places... well. In terms of false triggers turning the beacons on, I really don't have a problem with that --anything is better than having them blinking away all day and night. -or- get a good deal on some wall-plug transformers and have all the beacons AC powered and simply blinking all the time -but now plugged in.

This is just the basic picaxe IR set-up, the one with the 3-pin receiver. The only difference is that I stuck the receiver in the end of a tube with the inside painted black. With the receiver shielded this way, it can only see a signal coming directly in front of it. Badda boom badda bing.

ohhhhh thanks ! never got that thing working.

Am I the only one that sees a problem with the idea of 2 becons in a room?

turn a full 360 degrees or is it some kind of jiggery pokery with the gears? 



looks like an interesting project dude.  

The 360 comes from the gear ratio. The jitter comes from the fact that I am running on only 3 AA's and the backlight of the LCD is stealing a lot of the servo's juice.