Infrared Line Follower Kit - Coming Soon Part 2!!

Jessica Uelmen

Hello all!

About a week ago, I made an announcement that we would soon have a new Infrared Line Follower Kit for sale.

We're still tying up some loose ends as we are preparing this product for launch, but I thought I would take the time today and give you a sneak peak at the final draft of the documentation before the product goes up for sale! Hopefully it isn't too much of a tease and will give you an overview of what you can expect.

And the best part is ... drum roll please ... it's compatible with the Stingray! :]

I hope you enjoy this little teaser-doc - let me know if you have any questions and/or comments!

Cheers,
Jessica

erco

That's a hefty hunk o'hardware... I'm surprised you didn't go with smaller integrated IR sensors, like Hamamatsu... http://www.junun.org/MarkIII/Info.jsp?item=48

NikosG

Hi Jessica and erco,
In 2004 here in Greece I was subsriber in a robotic magazine that it was publised by "DeAGOSTINI".
That magazine offered gradually to the readers a Parallax board, a chassis, motors, hardware parts and some sensors.
One of those sensors was a Line follower sensor very similar to the " Infrared Line Follower Kit " mentioned above by Jessica. Here is a photo of this sensor:

As you can see the difference is that the above kit has 5 IR sensors (s1,s2,s3,s4 and s5) instead of 8 of the " #28034 Infrared Line Follower Kit".
The given Bs2 code by DeAGOSTINI was this:

' {$STAMP BS2}
' {$PBASIC 2.5}
led_on           CON 0
led_off          CON 1
W_line_B_Back    CON 0  ' white line & black background
B_line_W_Back    CON 1  'black line & white background
line_type        CON  B_line_W_Back

s1              CON 6
s2              CON 5
s3              CON 4
s4              CON 3
s5              CON 2

spostatiIn       CON 2

ledpos           VAR Nib
cont             VAR Nib
ifbits           VAR Nib
OUTL =%01111100
DIRL =%01111100
DEBUG "      Line Folower Control      ",CR
DEBUG CR
DEBUG "--------------------------------",CR
DEBUG "                                ",CR
DEBUG "  [   ][   ][   ][   ] [  ]     ",CR
DEBUG "   s1   s2    s3  s4    s5      ",CR
DEBUG "                                ",CR
DEBUG "--------------------------------",CR

DO
  GOSUB LF_sensor:
LOOP



LF_sensor:
     ifbits=0
     FOR cont = 0 TO 4
     LOOKUP cont, [s1,s2, s3, s4, s5], ledpos
     OUTL.LOWBIT(ledpos) = led_on

     PAUSE 1
     ifbits.LOWBIT(cont)= IN9 ^ line_type

     OUTL.LOWBIT(ledpos)=led_off
     DEBUG spostatiIn, (4+((4-cont)*5)),4,BIN1 ifbits.LOWBIT(cont)
     NEXT
RETURN

I have tested successfully this code on my Boe Bot. When you run the cobe you can see on debug terminal a "1" on the corresponding IR above the Black Line.
The reason I mention it here is because I tried to run the example code from the "28034- InfraredLineFollower-V1.0-DraftC.pdf" file given by Jessica.

' InfraredLineFollower_Simple.bs2
' Displays output states of the Infrared Line Follower using the Debug Terminal.
' {$STAMP BS2}
' {$PBASIC 2.5}
state VAR Byte
DO
state = INL ' Read input state of pins 0-7
DEBUG HOME, "state = %", BIN8 state ' Display states on Debug Terminal
LOOP

but it is not work.
What do you think? I must to change something? or there is no point to try this code with my hardware because it is not compatible with the original #28034- Infrared Line Follower kit?

Best regards,
Nikos

Jessica Uelmen

Hi Nikos,

It looks like the sensor that you have requires external signaling from the microcontroller. Meaning that the BASIC Stamp needs to send high and low signals to turn the LED on and off and then read the output state of the detectors.

The Infrared Line Follower Kit uses an ICM7555 chip to send high/low signals to the LEDs independent of a microcontroller. Therefore, the only code necessary for the microcontroller is to read the output states of the IR detectors and respond accordingly.

So it doesn't look like the sensor you have is compatible with the code for the Infrared Line Follower. It may, however, be more apt to working with the code for the QTI Line Follower Kit.

Cheers,
Jessica

Raymond Xiao (ParallaxHK)

erco wrote: »

That's a hefty hunk o'hardware... I'm surprised you didn't go with smaller integrated IR sensors, like Hamamatsu... http://www.junun.org/MarkIII/Info.jsp?item=48

Hi Erco, the IR sensor in your link looks like a normal light sensor. This kind of sensor is very easy to be interfered by ambient light when it works to follow a line. Actually, it won't work well and even doesn't work with 38kHz driver. When we designed #28034 Line Follower, we did some testing with this kind of sensor. Now, the sensor on #28034 Line Follower is really different from this one you mentioned. The sensor works at the carrier frequency of 38kHz~43kHz, it has very High immunity against ambient light. More, it can even detect different color some lines by adjusting the POT on the board to change the frequency. It is almost linear between the signal output and the carrier frequency.

GordonMcComb

Excuse bumping an old thread, but...

What is the center frequency of the IR receivers? My application isn't line following, and I'm trying to get the maximum range possible, which means dialing in the center frequency as close as possible. The furthest away I can get for consistent range is about 1.5". I'd like it to be more like 3 to 5 inches, which is the minimum I can achieve when I use discrete 38 kHz receivers.

Can the IR receivers tolerate a higher voltage than 5.5V? Increasing the voltage would increase the range. That is until the LEDs burn out.

A schematic would be really helpful, if that's at all possible.

-- Gordon

Raymond Xiao (ParallaxHK)

Hi Gordon,
The main purpose of designing the product was to let it to follow a line. I’m afraid it cannot reach 3 to 5 inches as you wanted for your other application. When turning the POT on the board to the position of 38.0 kHz, the infrared emitter and receiver pairs will reach its maximum detection range which is about 1.0~1.5 inches. When increasing the controlled frequency, the detection range is shorter. The power supply for the infrared emitter and receiver pairs comes from a 3V regulator. Increasing the voltage of VDD could damage the regulator and won’t increase the range .

RITESH KAKKAR

Hello,

can't we make Line follower by simple circuit using IR led 7 its receivers with op amps...??

RDL2004

I remember experimenting with the IR receivers that came with my BoE-bot and found that the peak response was in the 40-41kHz range. It could have been something in my set up, but it might be worth checking out.

asdf

Hi,

Could i get the schematic for the #28034 Infrared Line follower.

It doesnt seem to turn on when i power it up, so id like to troubleshoot