Bot Bench I'd Rather Be Building Robots
Ever wondered what an IR Seeker V2 looks like on the inside but didn’t have a spare $50 you could just throw away? Well wonder no more! I was given a pre-production IR Seeker by HiTechnic to write a RobotC driver for it. The lens cap on it wasn’t as clear as the production version so they sent me a replacement lens cap and sensor cover. That meant I had to do some minor brain surgery on the sensor casing. Armed with a sharp blade I went to work.
After removing the white plastic cover, the lens cap came off smoothly after a bit of prodding and poking. As you can see on the picture to the right, there are 5 IR sensors, each pointing in a different direction. The rounded lens cover ensures that they can all receive an undistorted IR signal. You can click on the picture for a bigger version which shows a bit more detail.
I wasn’t satisfied with just slipping the new lens cover on and closing it all up. No, I wanted to see it all. Slowly I pulled the small printed circuit board (PCB) out of its cover. I was not disappointed when I turned it over. The big chip roughly in the middle is the brains of the whole thing. It’s a very powerful processor that does all the Digital Signal Processing (DSP) of the 5 sensor inputs. It can detect both DC and modulated IR signals at 600 and 1200Hz. The small silver rectangle next to the main processor seems to be an oscillator or crystal running at 10MHz. I have no idea what the smaller IC does. You can click on the picture of the PCB to see a larger version.
So there you have it; the inside scoop. The guts of the IR Seeker spilled all over your monitor in all of their glory. Maybe not as shocking as the title led you to believe, but pretty cool none the less.
I know I am fascinated with the roomba and all, but do you think the IR seeker may be able to pick up on roomba’s “virtual wall” signal. I have 2 of those things laying around and it would be cool to put them to “NXT” use!
I did a little research and it looks like they put out a 500Hz signal modulated on a 35KHz carrier.
There is only one way to find out if this thing works with the Roombo’s virtual wall thing. Set the seeker to 600Hz and point it at the beacon 🙂 The carrier frequency for the IR Seeker is 38KHz, btw, so YYMV.
Hey thanks for your work. I want to build such a “Sensor” by myself. So there is the question what for a phototransistor is there obstructed. Can you read something like a serialnumber or so? Sorry for my bad englisch.
Greatings from Germany
I’m afraid I can’t. I’ve put the sensor back together again and it’s part of a robot now. They’r simple photo transistors. The TV remote receivers are not really great for this kind of thing. Although they are cheaper, they expect a signal around 35KHz (exact frequency varies depending on model). The real hard work is done in the processor on the sensor. There are 5 separate signal processing threads that are constantly working to filter the info from the sensors. Is there a reason why you want to make this sensor from scratch or is it “just because”? 🙂 Note that that’s a perfectly good reason!
I just want to build a Sensor for the Robocup and until now i couldn´t find Phototransistors that ignor sunlight and are so sensitive in the distance
Why not simply use the IR Seeker? It does all the work for you 🙂 The trouble is that you’re looking for an IR Signal, so anything that outputs IR (like the sun) is going to interfere with it.
Yes you are right but i want to build this Sensor for an arduino board.
Sure, but you can make your Arduino talk to the HT IR Seeker as well 🙂
Yes you can but it woulddn´t be so exact like i want it to.
It appears some of your pictures have gone AWOL 🙁
Yeah, unfortunately they were eaten when I migrated to the stand-alone WordPress.
Hello Xander,
do you still have the pictures of the open IR Seeker? I need them for a study project. I would be very greatfull!
Thank you in advance!
Hi Oleg,
I’m afraid I don’t have them anymore. I spent a good half hour going through all my photos on my computer, but I cannot find them at all. Sorry about that!
Regards,
Xander