The death of my SmartUPS 700My SmartUPS 700 finally died after about 10 years & two sets of batteries. One day it simply stopped working -- no power output at all. Of course, this happened just a couple of months after I replaced the batteries. Since I've been playing with my robot I thought there might be something of value in taking this apart. If nothing else, the two 12V 7.5AH batteries are still good.
The SmartUPS controller boardThe SmartUPS 700 controller board looked to be the perfect addition to my 'bot. It contains:
OK, now the fun begins. At the bottom of the controller board there's an 8 wire ribbon cable, so logically all I need to do is figure out which wire goes where. Given the IC info, I know I need the following:
+5, Gnd, Clk, Sin, Strobe
So already 5 wires are accounted for. There are two switches, each requiring a wire, that's 7 of the 8 that I already know about.
Next I scanned the back of the board, flipped it, & printed the result. This way I could look at both sides at once while tracing the wires. Here's the result (starting at the leftmost wire with the black stripe):
Testing the ResultI wired the result to my PIC16F877 using B0..B2 for Sin, Clk and strobe respectively. At this point I still didn't know what wire #1 was all about so I left it dangling. Working with the UCN5821 is trivial : set everything low, then strobe out the bits like this:
set strobe low set clock low for all bits (16 in this case) set Sin set the clock high set the clock low done set the strobe high set the strobe lowI do this first assuming bit 0 = off, bit 1 = on. Lights D45 and D38 are both lit unless bit 5 or 11 are set which turns them off. OK, the logic is reversed, so now I get D45 & D38 to blink. So far so good.
Another long look at the board & it seems like wire #1 needs to be connected to a positive supply. I start it out +5V. Sure enough other lights start to come on. Keeping off one bit at a time I can now light all of the lights except D50..53 and D40..42. These are the top four & three lights on the bar graphs. Obvisouly these must be wired in series. Sure enough, when I attempt to light D49 it works, D49 + D50 it works but get dim D49 + D50 + D51 -- no luck.
So, I change the voltage on wire #1 to +9. This gets me D49 + D50 + D51 + D52 though again with each new light the whole strand dims. Well, since the batteries are +12V it makes sense that maybe that's what's needed. Sure enough, +12V on wire #1 works. So, here's the result:
Misc. NotesI find this layout very peculiar, but I'm also not a hardware guy so maybe it makes perfect sense.
What am I going to do with this?Everyone likes blinkenlights. A robot could do hand-stands, back-flips, ironing, whatnot, but without blinkenlights no one cares. I'm thinking the two rows can show the power going to the left & right motors, ot the results of the front & right sensors. I'm not sure about the switches or the remaining 6 lights. I'm sure something will present itself.