Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How to connect a 50-51 segment led bar graph to a 10 segment thermometer circuit?

Status
Not open for further replies.
N

novaris04

Newbie level 4
Joined
Jan 13, 2013
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,326
How to connect a 101 segment led bar graph to a 10 segment thermometer circuit?

let me introduce myself a little before I start explaining the problem I have. I dont really have any experience on electronics or programming but I am able to read some electrical diagrams, pinouts and some idea on ICs, so please bear with me on this.

I need bar graph that lights up according to the temperature inside a computer so I found this website that details how to create one (https://www.circuitstoday.com/led-bargraph-thermometer). At the same time, I need a bargraph of a certain size, 75mm "tall", number of segments is not important.

The design specifies 10 led segments but all of the 10 led bargraphs I found are much smaller in size. The only 75mm bargraph I found are 101 segments. (https://www.aliexpress.com/item/101segment-75mm-led-Bargraph-display-orange/375676989.html)

The design also specifies a temp range of 60-80 deg F, which is 15-26Deg C. What I need is 26 degC to 36 or more.


Question 1. How do I connect an IC meant for 10 leds to a 101 led bargraph? As a last resort, I dont mind assigning 3 leds to the same temp setting, (where groups of 5 leds move together instead of moving one at a time)

Question 2. I don't understand the led wiring of the 101 led bargraph at all. Can someone help me on this?
 
Last edited:

Normally you need to download the spec sheet on the device in question (this applies to all devices in your circuit), however in this case a simple google search didn't
reveal much. It looks like the LED bargraph display has circuitry built-in, and possibly a serial or parallel interface. It is not compatible with the circuit with which you wish to interface
(and it is not possible to make it compatible; a complete redesign would be required, which is not possible without the spec sheet of the LED display).
You may be able to find ready-made modules that measure temperature and display on 7-segment LED displays on e-bay.
If you really want a 75mm bargraph, you could purchase 10 separate LEDs and assemble into the correct length.
 

Hope this will hellp you.

**broken link removed**
 
Last edited:

Looks like I was wrong, iukhan's diagram shows that you can use the FA/08 model if you wished with your circuit - but only "sort-of".
C1 would connect to R8.
However, it's not really using the full 75mm of the display (and again not much you can do about that without a much more complicated circuit).
Your best bet is 10 separate LEDs, assembled to your 75mm requirement.
 

sky_123 said:
Looks like I was wrong, iukhan's diagram shows that you can use the FA/08 model if you wished with your circuit - but only "sort-of".
C1 would connect to R8.
However, it's not really using the full 75mm of the display (and again not much you can do about that without a much more complicated circuit).
Your best bet is 10 separate LEDs, assembled to your 75mm requirement.
Click to expand...

if i connect C1 to R8, i would be able to drive only 10 out of the 100 segments? anyway, i chose the led bar graph because of its looks.
 

Correct; it's not possible to drive all 100 (even if you wished to group them into a set of 10 groups) with the circuit that you have, even with fairly extreme modifications.
 

If you could tolerate not all segments being used, then you could light 8-segments at a time using 10 groups, which would utilize a total of 80 segments. Would that be acceptable? If so you would need to add a resistor (R8) in series with each of the S1 through S8 connections to help equalize the current through each of the segments. The resistors would connect to the plus supply. C1 through C10 would connect to their respective output on the LM3914 LED control IC. Note that you must use the FK version of the bar graph for proper polarity on the LEDs.

If you wanted to utilize all 101 segments then you could use two LM3914 chips to control all 13 groups. The data sheet shows how to connect them for that.
 

iukhan said:
Hope this will hellp you.

http://img.weiku.com//waterpicture/2012/6/7/13/101_Segment_75mm_LED_bargraph_orange_634759349571912311_1.jpg[/I MG][/QUOTE]

that's a BL101-7504FA/08.

the link is for a BL101-7504FA/10

[COLOR="silver"]- - - Updated - - -[/COLOR]

[QUOTE="crutschow, post: 1187830, member: 459376"]If you could tolerate not all segments being used, then you could light 8-segments at a time using 10 groups, which would utilize a total of 80 segments. Would that be acceptable? If so you would need to add a resistor (R8) in series with each of the S1 through S8 connections to help equalize the current through each of the segments. The resistors would connect to the plus supply. C1 through C10 would connect to their respective output on the LM3914 LED control IC. Note that you must use the FK version of the bar graph for proper polarity on the LEDs.

If you wanted to utilize all 101 segments then you could use two LM3914 chips to control all 13 groups. The data sheet shows how to connect them for that.[/QUOTE]

one thing i cant quite understand is how does it control all 101 segments with 20 pinouts...
Click to expand...
 

novaris04 said:
........................

one thing i cant quite understand is how does it control all 101 segments with 20 pinouts...
Click to expand...
My scheme turns them on in 8 segment chunks.

If you mean how would you do each segment individually, that would be with a couple multiplexers. You apply power to the desired "S" and "C" line to light the desired single segment. All other lines are unpowered. If you want to make it appear that more than one segment is lit at a time, then you time multiplex the signals at a rate fast enough so the eye doesn't see any flicker.
 

i'll be closing this thread and starting a new one as I found a electrical diagram that allows for 3 led bargraphs that has the desired size.

**broken link removed**

thanks all
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top