John Parnum
Job role:Retired Engineer and Inventor
Skills:Engineering, electronics, robotics, prototyping
I am a retired Mechanical Engineer with a big interest in electronics controlling mechanical things. I create my machines using wood, aluminium, plastic, DC motors, batteries, servos, sensors & Arduinos. They are designed to be not too big so I can take them into schools as a STEM Ambassador to engage & enthuse children. My Lego Sorting Machine, Wheelie Bin Waste Robot, Local Delivery Robot, and Dinosaurs Automata have all proved popular with years 4, 5 and 6. I believe passionately in increasing STEM awareness in primary schools.
Recent project reports
I have now mounted the generator vertically.
Experimentation has shown that the generator needs to be turned faster, so I have increased the gearing. The orange cord has now been attached to the centre of the bounce platform and the generator tested successfully as it is generating volts. However, I have decided it will be better to mount the generator board vertically and not directly under the bounce platform. This will also allow it to be covered with a clear lid so the mechanism can be seen working.
The Arduino display needs to work with a SD card reader so that bmp images from a memory card can be displayed. Although challenging I have now successfully displayed a bmp image as shown in my photo. This image is not central - another problem to be solved!
I have made all the building blocks to realise Cole’s idea of generating electricity from a Trampoline.
I am using the same idea as the kinetic tile using a string (orange) attached to the centre of the bounce platform. A pulley and gears turns an electrical generator. As the voltage will vary from 0 to 10v I am using two DC to DC convertors to stabilise this at 4.2v so as to be able to charge the batteries. The generator unit will be mounted underneath the trampoline. A magnetic switch will count the number of jumps.
The system will use two battery packs each using two 18650 li-ion batteries. While one pack is being charged the other will power the display. Each battery (4.0v) needs to be charged separately while the display will run on two batteries in series (8v). The batteries and display will be housed in the custom wooden box which will be mounted on the handle of the trampoline.
