BOE-BOT Digital Encoder Kit Problems

JFlores

I've hooked up my new Digital Encoder Kit (DEK) per the documentation and I cannot get it to work using the sample program (Star_Pattern.BS2).· I also tried the calibration program from the related article on the DEK web page.

Inspecting my installation, I noticed that the·cales are reversed.· On·one side, the connectors are (top to bottom) red, white, and black.· On the other side, they are black, white, and red.· The cables are plugged into the headers correctly (i.e., I plugged them by lining up the raised edge of the plug with the corresponding groove in the header).· I follwed the instrcutions exactly, attaching the red wires to Vdd and the black wires to Vss.

Could this reversal of wire colors caused a component to burn out?· Is there some installation trick I don't know about or are the colors supposed to be reversed like that?· Is there a way I can test the encoders to see if they work at all or should I return them to Parallax?

Please help!

Thanks!

JFlores·····

Chris Savage

Hello,

·· The wires are not really reversed on one side…The connector is reversed in relation to the other side, but the wires connect exactly the same. Just out of curiosity, which documentation did you use? There were two different documents available depending on when you got your encoders. Both are located on the following web page. Also, what exactly is happening? You mentioned it did not work, but didn’t say how.

http://www.parallax.com/detail.asp?product_id=28107

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Chris Savage
Parallax Tech Support

JFlores

Both sets of documents look the same to me. I didn't see any difference. Is there some subtlety I'm missing?

I tested the encoders with the sample code on the documentation and with the code from the "Applying the Boe-Bot Wheel Encoders" document on the DEK product page. In either case, there was no reading from the encoders. My wiring matches the pictures in the documentation. I can send you a picture if you need it.

JFlores

Chris Savage

In one set the wires are colored differently than the other. Black doesn't go to ground in both manuals...

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Chris Savage
Parallax Tech Support

PAR

JFlores said...
Both sets of documents look the same to me. I didn't see any difference. Is there some subtlety I'm missing?

I tested the encoders with the sample code on the documentation and with the code from the "Applying the Boe-Bot Wheel Encoders" document on the DEK product page. In either case, there was no reading from the encoders. My wiring matches the pictures in the documentation. I can send you a picture if you need it.

JFlores

As Chris noted:

Boe-Bot Digital Encoder DataSheet (.pdf)· says:

The wires
are assigned as follows:
Red: Vdd
Yellow: Vss
Black: Signal (open collector)
Note· This is not a misprint. Black is
ground, but the signal output. The encoders
should be wired according to the following
schematic:

Note: DataSheet for kits shipped after Sept 1, 2005 (.pdf)· says:

The wires
are assigned as follows:
Red: Vdd
Black: Vss
White: Signal (open collector)
The encoders should be wired according to the
schematic on the next page. If your
wires are red, black, and , contact
Parallax for a different wiring diagram.

You have the red/black/white cables (you stated; "white", not "yellow", right?). So you should be following the second set of instructions (above), which is also what you stated you did (i.e., red to Vdd and black to Vss).

You can take one encoder at a time, unmounted, plugging it into the BOE-Bot's wiring board just like the instructions state. Then, modify the program to test just that one sensor (i.e., read just the signals from that sensor's signal pin, and print out a message using DEBUG to state whether or not the sensor is changing state). Hold the sensor in your hand and pass a IR-reflective surface close in front of the sensor, moving the surface close and distant from the sensor. The DEBUG window should indicate these changes in position of the surface.

PAR

JFlores

I did try testing the sensor without the motor by passing a piece of white paper in close proximity to it. No effect. I will check the code again to make sure I am pulsing it correctly. If you have an example, please pass it on!

My other thought is to try the program and view the sensor with a low light video camera. I can usually test IR LEDs this way.

If none of this works, do I need to send them back to Parallax? Are there instructions on how to return items? I'm new at dealing with Parallax.

Thanks for the help!

JFlores

Phil Pilgrim (PhiPi)

Did you remember to include the pullup resistors in your installation? Without them, you won't see any output from the sensor.

-Phil

JFlores

Yes, my configuration is EXACTLY like the picture in the documentation. I think I need to return thees encoders..

[noparse]:([/noparse]

J

Phil Pilgrim (PhiPi)

JFlores said...
I did try testing the sensor without the motor by passing a piece of white paper in close proximity to it. No effect. I will check the code again to make sure I am pulsing it correctly.

What exactly do you mean by "pulsing it correctly"? These sensors have a level output (high or low). They don't need to be pulsed. Can you post your test code, please?

-Phil

JFlores

http://www.parallax.com/dl/docs/prod/datast/28107.pdf

I used the code on this PDF for testing the encoders.

J