evalp@etek.chalmers.se (Laszlo Radanyi JR) (03/22/91)
Hi, I've just got myself into trubble. I want to be able to make analog adjustments for my latest project. The adjustments need to be fairly exact, so I have decided to use a digital incremental encoder with peripheral circuits. What I got was a 8-bit word, that I use to set a multiplying DAC. So far, so good...the problem is that I want to make a bar display of, say 32 LEDS to show the absolute position of the potentiometer. The only solution I have got is to take 2 4-to-16 multiplexers and hook up one OR-gate per LED so that if my input word selects the n-th LED, then all the LEDS under this one will be selected too. Only that I dislike this solution, because it is so complex. I need 8 IC:s with OR-gates, two IC:s with the multiplexers. So, is there a better solution to this ( 5 line to 32 ) problem ? It seems that some sort of "substracting" operation will be necessary. (Like: if selected LED position is less than the input word, then drive. otherwise don't. ) Puh ! Grateful for any help !! Laszlo Radanyi Jr at evalp@etek.chalmers.se
scott@hpcvca.CV.HP.COM (Scott Linn) (03/26/91)
/ hpcvca:sci.electronics / evalp@etek.chalmers.se (Laszlo Radanyi JR) / 3:19 am Mar 22, 1991 / >So far, so good...the problem is that I want to make a bar display of, >say 32 LEDS to show the absolute position of the potentiometer. It has been a while, but would an LM3914 bar-graph driver IC work? It takes an analog value and will drive a bar graph of 10 leds directly... Scott Linn
gboxman@cs.ruu.nl (Gait Boxman) (03/27/91)
In <3340014@hpcvca.CV.HP.COM> scott@hpcvca.CV.HP.COM (Scott Linn) writes: >/ hpcvca:sci.electronics / evalp@etek.chalmers.se (Laszlo Radanyi JR) / 3:19 am Mar 22, 1991 / > >>So far, so good...the problem is that I want to make a bar display of, >>say 32 LEDS to show the absolute position of the potentiometer. > >It has been a while, but would an LM3914 bar-graph driver IC work? It >takes an analog value and will drive a bar graph of 10 leds >directly... > >Scott Linn Furthermore, you can take more than one and concatenate them to drive, say 20 or maybe even 30 LEDS. Gait Boxman