[PD] Fwd: Sensors GPIO Raspberry Pi Pd

Julian Brooks jbeezez at gmail.com
Fri Apr 12 12:27:56 CEST 2013

Message resent for thread archives with smaller picture size.


---------- Forwarded message ----------
From: Julian Brooks <jbeezez at gmail.com>
Date: 11 April 2013 19:24
Subject: Re: [PD] Sensors GPIO Raspberry Pi Pd
To: Martin Peach <martin.peach at sympatico.ca>
Cc: PD List <pd-list at iem.at>

Hey Martin / list,

Finally got all the stuff and ...

It’s not working!

We spent the day soldering cables and connecting stuff up as per the Omron
‘App Note 01’ spec sheet.

Started off super-conservative using the  I2C level converter (case 3 page
4) http://www.adafruit.com/products/757#Blog/Flickr

We tried resistors on both sides (being super paranoid!) and then we took
the low (Pi) side ones off.

We then moved on to case 2 page 3 of this same document…

 At each stage we checked with “I2Cdetect –Y 1” and nothing was visible.

The grid shows no attached devices every time we run it.

We re-booted at every stage following the various online tutorials/methods
of setting up I2C GPIO on the Pi (checked & double checked).

 As you can see we’re using a pi protoplate:


In the photo I’ve attached the cables are coded as follows:

Orange           GND

Yellow            5v

Blue                SCL

Green             SDA

The white is also 5v for the pull up resistors.

The resistor values are 4.7k btw.

We have tested the cable that terminates at the sensor and all that is OK.

I put a multimeter on the GND and SDA solder points on the sensor itself
and got 3.7v…

I put a multimeter on the GND and SCL solder points on the sensor itself
and got 0.0v…

Don’t know if this means anything or could be useful to know!

Stuck and frustrated now but hey, 3 weeks ago I knew absolutely bugger all
about any of this and now I do (sort of).

I'm thinking we could do with the most basic i2c sensor we can find as we
have nothing to compare.

Tonight I'm going to d/l a fresh raspbian and start from scratch to check
that end.

Feel like if we can't get past the 'i2c-tools' tests we're screwed - never
mind getting it in and out of Pd.

Any thoughts/pointers/options from anyone will be really appreciated?


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