L293D used to reverse motor direction 7.8 vdc

[rjsutton]

I have a setup that uses 2 x 18650 3.7V 4000Mah batteries in series ( producing 7.8Vdc. Im trying to control a 6-9V dc miniature motor with 2 buttons 1 button to CW and the other to CCW
Ive been told that a L293d will work but ive blown up 5 so far
I think the problem is im imputing too high a current into the Vcc1 (pin 16) which calls for 5V (max 7) attached is a diagram i found with basic setup I would appreciate someone confirming the setup IF I REDUCE INPUT TO 5VDC
Also if i connected something to the end of the + 7.8v feed to reduce the current to 5V .
Im not electronics savvy so appreciate any help
Thanks Richard

[cropwell]

You will need to put the 7.8V onto pin 8 (VCC2) and all your switching and VCC1 have to be 5V. So you need a LM7805 voltage regulator to derive that 5V.

[rjsutton]

You will need to put the 7.8V onto pin 8 (VCC2) and all your switching and VCC1 have to be 5V. So you need a LM7805 voltage regulator to derive that 5V.

Hi thanks assume the lm7805 can just come off the end of the main feed ( going to vcc2pin 8) so betweem 8 and 16 or does it need dedicated feed?
thanks

[cropwell]

No, you don't need a separate input, you can connect the 7.8V from the two batteries to VCC2 and the input of the LM7805 (pin1). Pin2 connects to GND and connect the out put (pin3) to VCC1 and all control inputs through the switches.

[rjsutton]

Hi so as drawn now OR does the feed go straight to 8 and no feed to 9 ? if so does the common power for switches come off pin 9 or am i wrong again. appreciate the help

[cropwell]

5V output of the lm7805 goes to switches.

[rjsutton]

Hi Cropwell
mate as soon as i connect pin 3 lm78 to 16 on l293d the voltage drops from 5V to 2.56 and the motor power drops by about 50%
unhook pin 3 and gets 5v perfect
cant see where ive gone wrong i have 8.3 v at pin 1 LM78 and 8 on L29
motor connections 11, 14
switch power from pin 16,9
other switch wires pin 10,15
Have tries removing switch power at 16 and feeding both + sides from pin 9 but doesnt work
any help please?
also Doddy may have a thought

[rjsutton]

Thanks very much so im actually switching 5 v thru the switch but the output to motor 11 14 is the 7.8V ?
think ive got it now

[Doddy]

It's worth reading section 10 of the attached data sheet re. heatsinking - if you're drawing high currents:-

https://www.ti.com/lit/ds/symlink/l293.pdf

[rjsutton]

Hi
thanks Doddy
the motor is rated
mA: 120
Stall mA: 200
so dont think is very high so im not worrying about heatsink ( am i correct?