Need help with Node.js I2C /alternative

Hello everyone,

For a project I want to read some data from my I2C sensor and post it to a blockchain. I use Ethereum and the Geth client (which works on the omega2+ with SWAP) for the blockchain. To interact with the smart contract I wanted to use Web3.js which I want to run on Node.js. To keep everything in node.js I decided it would be a good idea to install a I2C module for Node.js.

This turned out to be a problem because all I2C modules I have looked (i2c and i2c-bus) rely on node-gyp when building. node-gyp is a build tool to compile native addon modules for Node.js. It uses a library called lpthread which is a link to the pthread library source. The problem however is that gcc or g++ don't have this library (they have pthread but not lpthread). This causes a crash when trying to install the i2c library.

This is the error I get (I can also upload the full error log if necessary):

root@Omega-45B9:~/read_i2c# npm install --unsafe-perm -S i2c-bus
npm WARN package.json read_i2c@1.0.0 No description[0_1496260846988_error.txt](Uploading 100%) 
npm WARN package.json read_i2c@1.0.0 No repository field.
npm WARN package.json read_i2c@1.0.0 No README data
\
> i2c-bus@1.2.2 install /root/read_i2c/node_modules/i2c-bus
> node-gyp rebuild

make: Entering directory '/root/read_i2c/node_modules/i2c-bus/build'
  CXX(target) Release/obj.target/i2c/src/i2c.o
  SOLINK_MODULE(target) Release/obj.target/i2c.node
/usr/bin/ld: cannot find -lpthread
collect2: error: ld returned 1 exit status
make: *** [i2c.target.mk:114: Release/obj.target/i2c.node] Error 1
make: Leaving directory '/root/read_i2c/node_modules/i2c-bus/build'
gyp ERR! build error
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/usr/lib/node_modules/npm/node_modules/node-gyp/lib/build.js:270:23)
gyp ERR! stack     at emitTwo (events.js:87:13)
gyp ERR! stack     at ChildProcess.emit (events.js:172:7)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:200:12)
gyp ERR! System Linux 4.4.46
gyp ERR! command "/usr/bin/node" "/usr/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /root/read_i2c/node_modules/i2c-bus
gyp ERR! node -v v4.3.1
gyp ERR! node-gyp -v v3.0.3
gyp ERR! not ok
npm ERR! Linux 4.4.46
npm ERR! argv "/usr/bin/node" "/usr/bin/npm" "install" "--unsafe-perm" "-S" "i2c-bus"
npm ERR! node v4.3.1
npm ERR! npm  v2.14.12
npm ERR! code ELIFECYCLE

npm ERR! i2c-bus@1.2.2 install: `node-gyp rebuild`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the i2c-bus@1.2.2 install script 'node-gyp rebuild'.
npm ERR! This is most likely a problem with the i2c-bus package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     node-gyp rebuild
npm ERR! You can get their info via:
npm ERR!     npm owner ls i2c-bus
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /root/read_i2c/npm-debug.log

I have all the lasted version as of 31-05-2017:
gcc: 5.4.0
make: 4.2.1
nodejs: 4.3.1
omega: 0.1.10 b160

So the questions are:
Is there a workaround for this error?
Is there an alternative for this error?

I guess I could have python do the talking to the I2C and the link it to web3.js and node.js via RPC or something, but its not preferred.

Diego Serrano

@Maarten-de-Klerk said in Need help with Node.js I2C /alternative:

get (I can also upload

I have same problem Need install i2c for node

jagabomb

I also needed lpthread so that I could install the i2c-bus module for the bme280-sensor package. Ended up running the code below and it worked.

ar -rc /usr/lib/libpthread.a

This created the missing file. Now npm has installed both i2c-bus and bme280-sensor.

Thanks to @Trey-Felton from this post:
https://community.onion.io/topic/3546/serialport-with-node-v8-10-0/2