Wednesday, March 29, 2017

Pi Touchscreen and Lightning Bolt

I've been working on some neat-o projects with a Raspberry Pi 7" Touchscreen on a Raspberry Pi 2 for a few weeks.

But, the Pi has been plagued by the yellow lightning bolt icon, which means "your power supply sucks".

Nothing I've tried, until now, has fixed it. I've been through several phone chargers in 1A, 2.1A, and 2.4A varieties, several USB cables, and I've tried a Pololu 3.5A step-down switching regulator, and my own prototype 3A step-down regulator (I think I broke it?!)

My solution: power the touchscreen and Pi from independent phone chargers, after disconnecting the 5V jumper between them. Hope this helps someone else.

Subscribe and stay tuned for a future article on my Jeep-mounted Overland Expedition Pi with offline Mapping, Satellite Telemetry and Messaging to HQ, and APRS.




Tuesday, January 17, 2017

My Western Electric 302


I've finally fixed my only vintage phone, an old Western Electric 302, and thought I'd share the old telephones' electro-mechanical guts.

Pulses

These old phones are how dialing a number became a thing. Instead of push buttons and DTMF, rotary telephones send pulses. And not with a 555 timer, either...



Monday, December 26, 2016

Making Slot Car Tires


As Christmas approached when I was a kid and Rudolph the Red Nosed Reindeer aired on the TV, Dad would return from the garage with an enormous box emblazoned with "Thunderbolt III" and a picture of two race cars battling to victory.


We set up the Strombecker slot car tracks and, grasping the blue speed controllers, we brought to life the epic struggle of white Chaparral 2D and yellow Ford GT 40 Mk II, father versus son.

I still have that old slot car set. And now a child of my own. And though Dad left this life in 2010 and mom passed away in September, they'd be happy to see my 7 year old daughter and I reliving those moments from my own childhood.

Except... when I finally unwrapped the cars, stored carefully 35 years ago, the tires fell apart in my hands. Rats.

After some online research, I discovered one can create custom slot car tires using a 2-part RTV silicone rubber. So that's what I did.