Holes in the starter pack

[motherhugger]

in the picture...the blue wire connected to the holes....what is the used of that holes?

the documentation says
blue wire ECHO output
yellow wire TRIGGER input

btw this works...just dont know how it went that way

 

[westaust55]

Those 8 holes from right to left are direct connections to the PICAXE outputs 0 to 7 inclusive.

There are cases where it is not ideal to connect to the Darlington outputs of the ULN2803. This is because the Darlington outputs are effectively a controlled switch which has its output either floating (neither high nor low) or very low resistance to ground (0V)

That is a good photo (for me) to hold for future reference as the topic of how to connect directly to the PICAXE does arise from time to time.
Unfortunately, the AXE020 board datasheet does not show or make reference to these holes in the layouts or schematic.

@Technical - it might be better if the links to the datasheets on the Rev Ed website page for the Products / Starter Packs page
went to the respective datasheets for the 08M, 14M 20M, 18X, 28X1
instead of the PICAXE Manual section 1.

 

[hippy]

Just from looking and "blue wire ECHO output" I'd guess the hole links to leg 24 of the PICAXE, Output Pin 3. Turn the board over and there should be a track showing such a connection, or use a continuity tester / DMM. You can confirm that - or determine the same - by looking at the program code; does it perchance happen to use Output Pin 3 for "ECHO Output" ?

You mention "documentation" but what documentation ?

What seems odd is that "ECHO Output" would seem to come from the U/S board, and "Trigger input" goes to the board - Yet this seems wired opposite to that, so shouldn't work; though it would with a PICAXE-28X2 - Unfortunately you don't say what PICAXE you are using.

If that's an SFR004 board ( again, you don't say what it is ) the blue wire goes to the "Trigger Input", yellow wire comes from "ECHO Output" which makes more sense.

So perhaps the real question is "What have I got here" ?

I'd say Blue wire is Output Pin 3 to U/S Trigger Input.

 

[motherhugger]

oh ok... got another question

http://www.rev-ed.co.uk/docs/srf005.pdf

YELLOW WIRE= ECHO "OUTPUT" (why does it connect to input pins?)
BLUE WIRE= TRIGGER "INPUT"(why does it connect to output pins?)

 

[westaust55]

hippy,
the photo shows an SRF005 U/S module. (its printed on the board)
But whether that is what motherhugger has . . .

 

[motherhugger]

i just got this from letsmakerobots.com its kinda confusing..anyway it works

 

[westaust55]

oh ok... got another question

http://www.rev-ed.co.uk/docs/srf005.pdf

YELLOW WIRE= ECHO "OUTPUT" (why does it connect to input pins?)
BLUE WIRE= TRIGGER "INPUT"(why does it connect to output pins?)

Your wiring diagram is correct.

The PICAXE output provides a signal to trigger the ultrasonic module. Triggering causes the SRF005 to output a burst of ultrasonic sound.


The ultrasonic module outputs a pulse the duration of which is related to the time for the ultrasonic echo to be received back by the SRF005 module. This signal goes to a PICAXE input so the PICAXE can measure the pulse length.

 

[motherhugger]

oh i get it now...why didnt i think of that... thanks

 

[westaust55]

motherhugger,

have you received or downloaded a copy of the AXE020 datssheet.
http://www.rev-ed.co.uk/docs/axe020.pdf
Have a look at page 2.

Those 8 holes you mentioned.enquired about are effectively in the 8 lines/ PCB traces from the PICAXE chip physical pins 21 to 28 inclusive going to the ULN2803 chip

 

[hippy]

hippy,
the photo shows an SRF005 U/S module. (its printed on the board)

Well spotted.

oh ok... got another question

http://www.rev-ed.co.uk/docs/srf005.pdf

YELLOW WIRE= ECHO "OUTPUT" (why does it connect to input pins?)
BLUE WIRE= TRIGGER "INPUT"(why does it connect to output pins?)

That's correct. "ECHO Output" is a signal from the SRF05 so needs to go in to an input of the PICAXE. "Trigger Input" is a signal in to the SRF05 so needs to be driven by an output from the PICAXE.