Playing with the grandkids.

Our daughter and her family from Pittsburgh came for their yearly visit. It has become a tradition that when they come, grandaddy helps them build some DIY electronics kit. Our granddaughter, 11, did very well soldering last year so I bought a line following robot kit for her. Uses 2 IR LEDs and 2 photoresistors feeding a pair of op amps to drive 2 separated electric motors so that it steers by adjusting the motor speed of the drive wheel on each side. Both electronic and mechanical and she nailed it. Oldest grandson, 9, soldered up a spinning top that uses a centrifugal switch to turn the power on to 2 flip flop transistors driving 4 blinking LEDs. He did very good soldering and measuring the component values before inserting them into the board but the kit came without any instructions so Grandaddy had to do a bit of figuring out the schematic and troubleshooting to get it working. Apparently, the solder leaked through the holes for the LEDs and shorted them out so they had to be removed and redone, figuring out the battery polarity (unmarked buttons), and testing all the components. Finally finished and blinking when spinning. His younger brother 7 and baby brother 4 weren't quite up to soldering. I did let the 7-year-old try a few times but he didn't really have the coordination yet to get it right. But they did put the components into a board using a microphone and LED driver circuit to turn the LEDs on when sound was detected and they were tickled every time they made noise to turn the LEDs on! Ah, what fun and wore grandaddy out!