[PD] Sensors GPIO Raspberry Pi Pd

[Martin Peach]

On 2013-04-11 14:24, Julian Brooks wrote:
> 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:
>
> https://www.adafruit.com/products/801
>
> 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…
>

If you have pullup resistors you should get the same 3.7V on SCL (with 
it switched on and not running any code), so probably your pin isn't 
connected somewhere.

Martin