Let there be light…

Have been getting frustrated with a series of epic fails recently. I want to measure current so I have a cheap Chinese version of a current sensor – that gives 0 -5V to represent +/- 20A. So 0A is 2.5V and I’m only going to use “+” so it makes sense to subtract off 2.5V so I can then have 0-5V for 0-20A. Most of what I do is mA stuff so why not amplify the signal and get better resolution? Seems OK to me. With that in mind I’ve been trying to prototype an “Instrumentation Amplifier” circuit on a breadboard. It don’t work. Really can’t see what I’m doing wrong. Bollocks!

Anyway, to improve my mood, here’s some shiny 🙂

IMG_20130427_172605

 

The LED is a ” 4-Pin Super Flux RGB LED Lamp Orca R Series (4.6mm Dome)”. There, I feel better already.

Bottom line is Forward Voltages of 2.6, 3.8. 3.8 for RGB and “Recommended” forward currents of 50mA. Peak currents are 160, 150 and 150 so not exactly pushing it then.

Shit, this thing is bright. The circuit board has a separate power supply. Even at these “safe” levels it needs 150mA to drive the LED at peak power. That would be 460mA if I maxed it out.

Unfortunately, it’s common cathode so I had to use 3 x P-Channel MOSFETs to drive it. For reasons I don’t understand they’re way more expensive than N-Channel and if this had been common anode then a simple, and cheap, as in chips, Darlington array would have sufficed.

I’m thinking I will find an ultrabright common anode RGB LED, and some more ping pong balls, obviously, to make some kind of lighting thingy. In the meantime, I intend to drive this thing to within an inch of it’s life to see if I can melt the ping pong ball I stole from the cat’s toy collection today. The board takes up way too much space and the wiring is a pain in the arse – guess that means I need to at least hit EagleCAD and get some smaller boards made in China (10 for $10US I think).

Fairly sure we could do something with kit like this either around the place or out on the patio. So, fairly sure she’ll understand the expenditure of time, effort and money then :-#

This wouldn’t be a proper post without a shit video from the shit video camera on my excellent mobile phone…

[embedplusvideo height=”496″ width=”625″ standard=”http://www.youtube.com/v/tdA_-d6byS8?fs=1&hd=1″ vars=”ytid=tdA_-d6byS8&width=625&height=496&start=&stop=&rs=w&hd=1&autoplay=0&react=1&chapters=&notes=” id=”ep9601″ /]

It was bright in there, I shut the extremely thin curtains at some point to help out. It really is seriously bright 🙂

 

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

*