I have a Raspberry Pi 2+ . Now I want control a light sensor ( TSL2561 ) . I connected it to the following schedule :

enter image description here

Where I connect the 3V to the 3V0 (not in the picture) and now to the VIN .

i2cdecect -y 1 provides me an empty table .. Can someone tell me what I did wrong?

Where the red cable goes to my first pin (3v)

enter image description here

  • The most likely explanation is incorrect wiring. Add a photo of the connections to the question. – joan Feb 13 '16 at 11:28
  • The black wire seems to be in pin 7 (GPIO4) rather than pin 9 (ground). – joan Feb 13 '16 at 11:35
  • The connections are not soldered, the module seems to be placed over some header pins inserted in the breadboard. Loose connections are a killer for I2C. – joan Feb 13 '16 at 11:39
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    If you do get this solved, please leave an answer of your own. I don't think those PCBs work well unless you solder the pins on. It is not hard, just follow a guide (heat the pin and the hole, not the solder, let the solder melt from the heat accumulated by the pin and hole, wait a second or two for the hole to fill once the solder starts to liquify) and of course remember to inhale as much of the smoke as you can. – goldilocks Feb 13 '16 at 14:19
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    @goldilocks that final advice is off-topic here, please take it to health.stackexchange.com – Ghanima Feb 13 '16 at 15:55

Your pin headers aren't even soldered to the light sensor's PCB board. It will not make contact properly if at all.

Solder them on for best results or press down on the opposite end near the screw holes as a temporary solution. Make sure they make contact.

Figure 1: Me pressing down on unsoldered Arduino Pro Mini so I can upload something to it. enter image description here

Source: Experience and laziness

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  • Thank you and im so sorry. Soldering solved the problem, – SuperFliege Mar 16 '16 at 18:34
  • @SuperFliege You may mark this as the answer if it helped you out. – PNDA Mar 18 '16 at 11:38

check your connection properly. if you dont have any experience with soldering get a pi i2c adapter or if check i2c voltage level for sensor. make sure they are same. if you use an i2c adapter it will take of i2c connections and all kinds of voltage level. you can check here. Raspberry pi I2C adapter

if you want to make it more easy then you can get a TSL2561 sensor with a i2c connector, using i2c connector you can directly connect sensor with pi in few seconds. and you dont have to worry about any wrong connection or voltage level.

lot of time devices doesn't respond just because of bad hardware connection.

after connecting all your hardware make sure you have installed I2C tool. if you have it then just run sudo i2cdetect -y 1 , it will respond with an address 0x39. at this point you are good to go.

you can find the code here. TSL2561 raspberry pi java,python code

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