10 LED sequence light

[popicop]

Hi there, ive ben trying to make a circuit that:

• when you turn it ON it lights up 10 LEDs in sequence (0,1,2,...9,10) until they are all lit (and stay lit)
  
• And when you turn it OFF thay turn of in sequence backwrds(10,9,8,.....1,0) until they are all off (and stay off)
  
• The period of time bettwen each LED is arround 100mS.

I tried using a LM3914 UV meter with a capacitor at the Rx and works great only when the batteries are full. I need a hole other solution.
I was tempted to program a PIC 18A (arround $2.50) but ill be more that happy to here what the experts have to say

 

[ljcox]

Hi there, ive ben trying to make a circuit that:

• when you turn it ON it lights up 10 LEDs in sequence (0,1,2,...9,10) until they are all lit (and stay lit)
  
• And when you turn it OFF thay turn of in sequence backwrds(10,9,8,.....1,0) until they are all off (and stay off)
  
• The period of time bettwen each LED is arround 100mS.

I tried using a LM3914 UV meter with a capacitor at the Rx and works great only when the batteries are full. I need a hole other solution.
I was tempted to program a PIC 18A (arround $2.50) but ill be more that happy to here what the experts have to say

0 ~ 10 is 11 LEDs, not 10. So I assume you mean 0 ~ 9.

You could use a 10 stage Shift register - one that has direction control. It would be configured to shift right until the tenth stage is set, then set a FF to make it shift left.

 

[popicop]

You are right LJcox, 0 to 9
Im not very experienced on circuits though, not at all. Hek, its the firts time ive herd from such part.
Does this solution (10 stage shift reg) need more than put together a circuit from a schem?
Do you have a schem LJcox?

 

[popicop]

An 8 LED sequence would do just fine but i REALY need help putting this together. Please check out this link, the first of the circuits (16 LED Seq) appears to do a similar task. I will go for a single 8 stage Shift register.

**broken link removed**

PLEASE HELP!!!!

 

[audioguru]

An LM3915 will work perfectly. Its timing capacitor will charge exponentially and its logarithmic response will convert it to a linear activation of the LEDs when the power is turned on. If it has a huge capacitor to power it then its LEDs will turn off one-at-a-time when the power is turned off.

Your LM3914 has a linear resonse so its LEDs would have the first few lighting quickly then the last few lighting slowly as the timing capacitor charged. Then you forgot to power it when the power was turned off.

 

[popicop]

I did manage to make the LM3914 work as i wanted BUT the device will run with batteries and the up/ down motions variates to much as the batteries wear (not much wear is needed for it to not work the right way)

 

[audioguru]

I did manage to make the LM3914 work ...
BUT the device will run with batteries and the up/ down motions variates too much as the batteries wear

The LM39xx has a built-in regulated voltage reference that can charge the timing capacitor to the same level each time even if the supply voltage changes a lot.