Some of the student projects I was helping with 2013/4.
These were from the EME students, half way through their course. They’re all on a very tight budget of around £100. Working on such a tight budget is quite deliberate – it gives an extra ‘challenge’ to these student projects and really forces them think about what they are doing!
This first video involves a small hovercraft and two line following robots.
Two motors on the hovercraft, one for lift and the other for forward (or backward) motion. It also had ultrasonic sensors on the front to detect obstacles and automatically guide the vehicle away from them. Arduino controlled. The user control was by a games console controller, connected to the hovercraft via bluetooth.
The two line following robots used a strip of optical sensors to detect and follow a line. The trick here is what happens when there’s a break in the line or two lines cross. Also what happens if the device looses the line such as in a tight corner – how does it recover? That’s all down to the coding of the Arduino processors used.
Next is a video of a rudderless boat, a tower climbing inspection robot and a rolling ball / Congreve clock.
Two independent motors on the boat providing differential steering. This method of steering can provide a very high level of manoeuvrability. Slots towards the front were for ultrasonic sensors for the detection of obstacles (jetty, harbour walls, other vessels), though these sensors were never fully integrated in.
The inspection robot ended up using three powerful magnets to keep it attached to the ‘tower’ surface. Wireless remote control feeding through to an Arduino where these signals were combined with internal gyro signals to provide directional stability. A Raspberry Pi (cross-connected to the Arduino) was used for inspection camera control.
The idea behind a Congreve clock goes back to the early 1800s. The timing control is determined by the length of time it tales for a ball to roll down a track. Once it reaches the end it triggers a mechanism that tips the track and sends the ball rolling back in the other direction. Again Arduino controlled for sensing when the ball has reached the end of the track and for then for the tipping action, and then using this information to calculate (and display) the time.
Th final video involves a solar water heater, a four legged walker and a quadcopter.
For the solar water heater an offset feed satellite dish was coated with reflective silver paper, and at its point of focus a (black painted) copper tube was mounted. Through this tube water was pumped and absorbed the heat concentrated on it. An Arduino was programmed with information on the sun’s location, and then controlled a motorised system to rotate the dish so it would always be at the optimal position for solar energy collection.
How do you make something with four legs still remain upright when you remove one of the legs, and even have it move in this condition? Not an easy thing to do. Each leg had two servos, one for lifting the other for rotation. Careful placing of the controlling Arduino, battery pack and other components ensured that the centre of gravity was such that it still remained upright when only supported by three legs.
You can buy small fully functional quadcopters very cheaply, however designing and building one yourself from scratch is another matter. Sorting out power control, motor synchronisation, balance, weight constraints, reaction to erroneous movement… all take some thinking when you can’t just go and buy a self-contained kit but have to calculate these yourself.
These student projects are always interesting. This is often the first time they will have worked together in such a way, and having been told a desired outcome they must start totally from scratch, research, design, liaise with workshops to get items manufactured, contact outside companies to get components (cheaply – can we have a free sample please!) and then construct and get working their device, all in a limited time frame, tight budget, and on top of their other study work.