Powering Pic16F84A

[ericgibbs]

Can I ask for the diagram? I could not find the specs of CD754410

hi,
I cant find the CD754410 data ?

Have you tried a NiMH battery pack??

 

[paparts]

Re:

Have'nt yet maybe tomorrow coz its night time here. Ill give you an updtae on how I will solve it if ever. I have an idea using LM7805 a voltage regulator. My friend used a voltage regulator and it went well.

 

[ericgibbs]

Have'nt yet maybe tomorrow coz its night time here. Ill give you an updtae on how I will solve it if ever. I have an idea using LM7805 a voltage regulator. My friend used a voltage regulator and it went well.

You cant use a 7805 with a 6 Volt battery pack.

 

[mvs sarma]

1. How far it would be proper to drive BD436/436 transistors from thr port pins of PIC16F884 without even base current limiting resistors?

2. Whether the PIC cant be tried at 4.5V which is amounts to use three cells

3. After somuch extensive circuitry and anticipated load current , perhaps it would be appropriate to use a 6V lead acid battery of 2 or 3AH capacity and try using LDO regulator for supplying the PIC.

 

[Nigel Goodwin]

1. How far it would be proper to drive BD436/436 transistors from thr port pins of PIC16F884 without even base current limiting resistors?

Don't do it!.

2. Whether the PIC cant be tried at 4.5V which is amounts to use three cells

Works fine, it's common practice.

3. After somuch extensive circuitry and anticipated load current , perhaps it would be appropriate to use a 6V lead acid battery of 2 or 3AH capacity and try using LDO regulator for supplying the PIC.

Easiest method is to use 6V for the motors, and 5V regulated from a seperate 9V battery for the electronics - this cures LOT'S of potential problems.

 

[mvs sarma]

Hi, Nigel,
I was aiming these comments on the schematic posted by Paparts on 27th instant.

 

[blueroomelectronics]

google cd754410 or l293d same pinout. The l293 might be easier to find, it'll work with small dc motors up to 600ma (the cd745510 will handle 1.2a)
Carbon Zinc batteries have a much different discharge curve than NiMH. Plus NiMH AA are about 1.2v per cell so four will give you 4.8v fully charged.

 

[mvs sarma]

google cd754410 or l293d same pinout. The l293 might be easier to find, it'll work with small dc motors up to 600ma (the cd745510 will handle 1.2a)
Carbon Zinc batteries have a much different discharge curve than NiMH. Plus NiMH AA are about 1.2v per cell so four will give you 4.8v fully charged.

All said, for a robot project, it is preferabale to go for high capacity and light weight batteries as these have to be carried on the body of the robot. As such perhaps two li-ion celles in series may be better provided re-charging system could be managed.

 

[blueroomelectronics]

Li-Ion cells are somewhat expensive and require an exotic charger to keep from exploding. They hate being abused and a short might anger them (see explode, fire etc...)
NiMH are common and more forgiving.

PS the OP seems to be having a difficult time giving up on the Carbon Zinc cells.

 

[mvs sarma]

Li-Ion cells are somewhat expensive and require an exotic charger to keep from exploding. They hate being abused and a short might anger them (see explode, fire etc...)
NiMH are common and more forgiving.

PS the OP seems to be having a difficult time giving up on the Carbon Zinc cells.

There are fresh cells named 'ZIC CHLORIDE CELLS" and these give better discharge rates. they are generally used for photography at nominal cost -- unlike Duracells.

 

[paparts]

Re:

I am removing the 555 timer and I think Alkaline or NiMH batteries will work

 

[paparts]

Finished

The line follower worked. I seperated the supply of the 555 timer and the pic16f84, full bridge ckt. and the sensors. tnx guys