This page is a brief account of what projects I am up to in my free time.
Live stats from my greenhouse: This data is via an Elecfreaks IoT kit which is an addon for the Microbit. It works with Thingspeak (Matlab) and since I had an existing account, I decided to give it a shot. Data sharing is set to public. My twitter bot was tweeting this data every morning as well until it got blocked as I accidentally decided to put its date of birth to be the lockdown of 2020 and Twitter was onto it, right away.
Project #2 – Modded sumo bot (Design taken off the original SumoBot https://github.com/makenai/sumobot-jr )
While students were building their sumo bots in the Robotics class, I have been working on my own Sumo bot except that I decided to try and make a line follower using the sumo bot design. This needed a bit of alteration to the design. The front panel of the bot was undone and I used it to host 5 IR sensors. These five sensors were screwed on the panel which was then attached along its side facing downwards. I used a servo shield (about $3 on AliExpress) to attach all the sensors. I guess I might end up adding some Ultrasonic sensors later too.
I have a splendid eBook called Arduino Robotics by Warren, Adams and Molle (Technology in Action) which had an example of a line follower called Linus that suited my purpose completely except that they used DC motors. My challenge was to appropriately code it using continuous rotation servos and replace the code for the DC motors.
Challenges faced: Not too many as it was an easy replacement of DC motors with servos except for the few coding difficulties. Screwing the IR sensors was tricky and needed to be approximately equidistant from each other. I plan to replace the NiMH battery pack with a LiPo. A 2S – 3S (7.4V-11.1V) should be good enough. The connectors will need some conversions. LiPo’s usually have a XT60 or DEANS adaptor while the standard Arduino has a barrel connector. With some simple soldering the plug should be ready.
Project #1 – Rebuilding an old RC car
This page is dedicated to my current projects. I decided to keep an ongoing project to test/improve my skills in robotics, construction and programming. It’s an official reason to ‘tinker’ and learn from tinkering which I can then apply and utilise in my professional teaching methodology.
My first project was to rebuild an old RC car using an Arduino. I saw this cool RC mod project (Click here) and was highly impressed. So I picked up an old RC at the local OpShop and began to deconstruct it. The logic was to replace the existing brain with an Arduino while keeping the DC motors intact. All I needed was an Arduino board, a motor shield (to power up motors), an ultrasonic sensors for range detection and I used the existing battery pack to power up the shield.
Problems I faced while doing this: The battery pack was well worn. It drained out really quick. Probably because the motor shield took up to 12V and the battery pack was a 9.6V (was a pack of 8×1.2V rechargeable AA’s combined as a unit). Using a LiPo would definitely be ideal. The motors were also an issue with an audible hum. The shield recommends to use motors above 4.5V upto 12V. The current motors would have been much smaller I imagine. Declaring the frequency (MOTOR 12_8KHZ) in the code while setting up the motor pins might have helped a little. More information is found on the the Adafruit Data Sheet.
Costs: The Arduino cost me $8, Motor shield was an Adafruit copy off Aliexpress for $5, Ultrasonic sensors are at $3. The car cost me $2 in the local opshop. I am keen to make my own Arduino sets after reading it in a project handbook.
The reasoning behind doing this project was simple. I wanted to use this as an example for the application of Robotics. Students most seldom think that old and broken RC cars can be reused. While they were learning about Arduino in their Robotics club, I decided to work on this car to show the wider applications of the Arduino module. One of my forthcoming projects will be to build a robotic arm.