Random Projects

A collection of small/random projects that cannot be put in a repository of their own.

---

Home-made flex sensor:

• Making a flex sensor with a pencil, a piece of paper, two wires, plastic sheet.
• Following the instructions in this video.

Line detection using Picam:

• Processing the output of a picamera to obtain the position of a curve or line.
• To be used with line-follower projects.

Home-made flex sensor version-2:

• Making a flex sensor with a pencil, a piece of paper, two card paper pieces, two pieces of aluminium foil: following the instructions in this article.
• Structured a frame for using it on my finger: using two ribbon pieces. Code for actuating a servo based on my finger movement(fingering?). Checkout the video.

Home-made pull sensor:

• Making a digital pull sensor out of a hexnut, some cardboard, two wires, a spring, and some glue.
• Pulling on the sensor closes the connection between the two wires. Thus the two possible resistive states are HIGH and LOW (digital).
• Connect red wire to +5v and white wire to voltage reading instrument (such as i/p pin on arduino). Pulling the red wire will cause a signal at white wire.

Calibrate:

• servos have to be in 0 angle to place them properly while constructing casings for a project.
• due to physical adjustments, they are usually not in their 0 angle and need code to get them there.
• this script will recalibrate the servos.
• attach the servos one by one to pin 12 of arduino.

Comms (M2M):

• python scripts to use mqtt.
• publish and subscribe information from/to several devices simultaneously.
• requires python libraries 'mosquitto' and 'paho-mqtt'.
• lightweight and can be integrated with windows (mqttbox) or android.

Comms (user):

• python scripts for various comms.
• script that send sms using fast2sms service.
• script that sends a phone call using twilio services.
• script that sends email using smpt and email libraries.

Indexer:

• choose a directory to get index for.
• the script will create an index file for the whole directory.
• includes proper file types and marks folders as folders.
• includes proper indentation to show parent child relations.

Localization:

• opencv trained haarcascade filters are contained in the haarcascade folder.
• we can use the filters to localize specific items in images.
• for example: get bounding boxes for human faces, cat faces, etc.
• localize.py script contains the code for loading and using the filters.

Speech:

• getfv script can be used to get feature vector from recorded wav file.
• record script has two useful functions.
• 'record' function allows us to record time samples of audio directly using python.
• 'say' function allows python to play any array as a time sampled audio.

Resistance:

• automatic resistance value calculation.
• implemented as gui, can handle 4 band as well as 5 band resistors.
• select colors from radio buttons and click calculate to see resistance.