If i follow my charger datasheet. It says i think:
2 AA @ 2.8v (360mA) +/- 10%
so 4 would be double?
4 AA @ 5.6v (720mA) +/- 10% ? Doesnt seem right or is it?
If anything i would make 2 separate chargers in 1. Like when connected to charger a PNP will OPEN the circuit leaving 2 AA & 2 AA not connected also a PNP wil open circuit to main power and will power device until unit is removed and power is restore battery wise. Does that malke any sense?
hi,
The sums look OK to me, looking at the discharge graph of your cells, assuming good fully charged cells,
whats the cell voltage after 8 hours at both discharge currents [ with/without LED B/L]
Looking at the graph it looks flat at 1.2V for most of the 0.2C rate.
Next step would be to run the project for 8 hours, from fully charged, note the voltage
then keep the test going until the cells goto 1.1v [ 5.5V]
Type of Vreg, it must be LVDO +5V rated at least 250mA
You can get LVDO's with a 0.45V drop out.
Do you follow OK.?
EDIT: I would estimate 12 hours with the B/L ON and about 24 hours with it OFF.
im loving those estimates lol. I have to reread the post but the first thing about the graph is confusing can you rewrite the question please. Um i would have to order the LVDOs but will they have same pinout as the 7805? (im sure they are smaller form factor) Or are they 220 case? Any links to some?
ok just made my variable power supply lol. So small and simple. Rectifier and all. I will try what you said before about testing minimums. Here is it(the psu):
im loving those estimates lol. I have to reread the post but the first thing about the graph is confusing can you rewrite the question please. Um i would have to order the LVDOs but will they have same pinout as the 7805? (im sure they are smaller form factor) Or are they 220 case? Any links to some?
Cct1 is a 150mA LVDO +5Vreg, with the B/L connection before the Vreg, push button for the B/L
Cct1 is a 1Amp LVDO +5Vreg, B/L on the +5V line, push button for the B/L
Cct3 is using the B/L LED's and an extra diode as a shunt regulator, giving a +4.6Vnom for the PIC logic, B/L must always be connected... its the el-cheapo version.
Ericgibbs:
i think i would use the 1amp mostly because i know i will be adding things to this like at least:
1 LED
1 IR LED (Maybe some zigbee wireless)
This is going to be the transmitter really. I want to be able to send commands to a main module like. This will be a wireless transmitter. And the main will be anywhere from 25-80 ft away. I will be sending just like IR a device code and a command. But i dont want to use IR. I want another wireless solution.
So if i press PC button and press 1 key i want it so send
00010001 = pc
00000001 = 0x01
So the data sent would be:
00010001 00000001
I might make it single byte like
0001 = PC (HIGH nybble)
0001 = 0x01 (LOW nybble)
so 00010001 would be PC and Key #1
But the single byte leaves me with a limit of 15 devices and 15 commands. Which is actually enough. So 1 byte it is! lol
hi atom,
Looking at the sparkfun pair, if you are using PIC's for the master and remote stations, have you considered using ascii and the UART for the commands.?
will switching it off actually save me much power? Remember if its lasing 12 hours on a charge now i dont mind loosing a few hours by leaving it on. My goal was for a 8hr up time.
will switching it off actually save me much power? Remember if its lasing 12 hours on a charge now i dont mind loosing a few hours by leaving it on. My goal was for a 8hr up time.
If you're using plain licence free modules, you should use Manchester coding (or similar), just sending plain RS232 doesn't work for various reasons - check my tutorial.
so ill leave it on most likely. Just to save on coding
Just got my dipmicro order in . Mostly LEDs and 2 proto boards (not for this project) some 20mhz crystals and 18F448 and Some Toner Transfer. (lol now i need printer)
Took about 9 days to get here (i ordered on Aug 1) Also i ordered from futurlec and nothing yet.