paparts

I have just finished a project using PIC16F84A micro. my project runs using computer power supply of 5 volts. but when I used 4 pcs. 1.5V battery the project don't work properly. I tried this site (http://www.talkingelectronics.com/ht...A-Project.html) but it doesnt work. Can you help me how I will do it?

ericgibbs

Which type of battery are you using? standard alkaline or rechargeable and do you have a diode in battery connections>

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

paparts

I' using a carbon zinc battery. I followed the 6 to ~5.3v conversion given by the poptronics site. I used the 1N4002 diode.

donniedj

Remove the PIC from the picture.

1. Measure the voltage of each cell.
2. Measure the voltage of the combined cells.
3. Connect diode and measure the combined voltage again with diode.
4. Attach a resistive load which will draw equal amounts of current expected from the PIC.
5. If you have a scope, monitory any ripples.
6. If resistive load pulls desired current and battery supply maintains proper voltage and ripple, then you can now scratch the new supply off the list of faults.

Swap PIC in question with another known good.
Get back to me when these are done.

paparts

Does the type of battery matter? whether it is an alkaline or a carbon zinc?

Nigel Goodwin

Only in that normal batteries are crap! - they don't last long under any sort of load, and under a heavy load may drop too low to use.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

paparts

What if I'l get less of 5.5V with the battery ? Does current matter? How do I measure the ripples? What I have here is just a multitester.

Nigel Goodwin

What are you feeding from the battery?, and presumably you've got an electrolytic across it?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

ericgibbs

hi,
Its just possible that the problems are not caused by the battery supply.

As we have no circuit to guide us, do you have any decoupling capacitors on the circuit board??

Is the battery/power supply, powering other devices in addition to the F84 PIC?

Do you have a PIC reset switch for the PIC? and/or a switch from the battery to the PIC supply???

Can you post a circuit?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

paparts

from this link(http://www.talkingelectronics.com/ht...A-Project.html) I used the 6 to 5V conversion.

Nigel Goodwin

No, we need to see the rest of the circuit!

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

ericgibbs

Did you see my questions in my last post

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

paparts

sorry i did not see what you post previously. Yes the battery is powering 2-LM741 for my line follower and 555 for my siren and the motor driver

ericgibbs

OK,
Can you answer these questions?

As we have no circuit to guide us, do you have any decoupling capacitors on the circuit board??

Do you have a PIC reset switch for the PIC? and/or a switch from the battery to the PIC supply???

Can you post a circuit?

It may seem we are asking lots of questions, but without your answers we cannot give the best advice.

You may know your project, but we dont.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

paparts

Here is my ckt. diagram