3 Colour LED Charge Indicator - opinions?

[posplayr]

Man... I wish you brains could figure out a better or replacement way to do the electronic tachs in some of the later model GSs.. After so many years, they'll get awful screwy... Ive installed 3 different boards in mine, and they were all wildly off at one side of the powerband or the other..

Sorry, Josh no time for that anymore. Even my mechanical one bounces alot.

[bakalorz]

Man... I wish you brains could figure out a better or replacement way to do the electronic tachs in some of the later model GSs.. After so many years, they'll get awful screwy... Ive installed 3 different boards in mine, and they were all wildly off at one side of the powerband or the other..

Are there pots to adjust, and maybe bring it into calibration ?

Also, my understanding is that electrolytic capacitors dry out over the years and change a lot in value. A first quick and dirty shot to try to fix it woud be to just replace any electrolytic caps with new ones of the same value. The value should be printed on them.

[pete]

I breadboarded a 3 color solid/blinking LED with a PIC a couple of years ago using a Red/green/yellow LED. Wrote about it here too. I personally didn't care for the look/functionality as much as a 20-LED "bargraph" built with 2 LM3914s (looked kinda like posplayers 2nd link but with 20 LEDS)

FWIW, what I mean by functionality is: With the bike runnning, the voltage is not a constant voltage, it oscillates quite a bit around the average, and the 3914 type shows this as a "smear" in the display. I not only thought that looked neat, but it also gave LOTS of info about the charging going on ... the smear was darker where the voltage spent the most time, and showed both the high and low voltages that the oscillation was going to. response time was VERY fast, so you could easily see how the charging changed with blips of RPM (as opposed to digital meters, which have to average over time) ...

But anyway, the PIC version is dead simple (and cheap ... probably under $5)
It only requires a PIC, red/green LED, four resistors and 1 bypass cap.
If you do it as SMD you might be able to fit the whole thing UNDER a 10mm LED.
Even if you use leaded components, its only an 8 pin DIP for the PIC.
You would want to use the HV615 PIC: it has a voltage regulator (to make it easy to run from the bikes power), an A/D converter (to sense charging voltage), and a PWM circuit (to change color easily) built in.
The default project people use to learn about PICs is making a LED blink ... this project only adds a little bit of complication in that it does so in response to voltages sensed by the A/D ...

If anyone wants to build a PIC version, I'll give more advice, and sample code (not completed though, I used a pot to emulate changing the voltage cause it was easier to run on the breadboard in developement ... but thats a pretty trivial change)

If anyone is interested in the LM3914 version, I still have a writeup I did with pictures, schematics, layout, etc somewhere.
The 3914 voltage monitor was done on premade circuit boards available at radio-shack (part #276-170), and required no particular electronics experience, just the ability to solder. Parts are probably $10-$15.
I liked this much better than a digital display (I rubberbanded a multimeter to the handlebars for a while)
It was easy to read at a glance, gave good information, was easy to read in all kinds of light (night to bright sunlight)
Size was about 3 inches wide, 1 inch high, 2 inches deep.
If and when I get around to it, I'll probably redo it to be 2 x 0.5 x 2
I rubberbanded mine to the top of the instrument cluster.

Martin, this is an ancient post of yours, but I stumbled across it just now looking for info on LED brightness.

Do you still have the details for your bargraph at all? I'm keen to have a look at that myself.

I want to see under and over voltage on the dash the instant it happens, but I don't like the idea of having to interpret blinking rates of LED's, I just want a simple guage like your bargraph.

[bakalorz]

Martin, this is an ancient post of yours, but I stumbled across it just now looking for info on LED brightness.

Do you still have the details for your bargraph at all? I'm keen to have a look at that myself.

I want to see under and over voltage on the dash the instant it happens, but I don't like the idea of having to interpret blinking rates of LED's, I just want a simple guage like your bargraph.

Attached is a bitmap with the layout, and following is the text description.
I have pictures somewhere of mine, if I can find them I'll post.
... then you can OOOH and AHHHH the cardboard and duct-tape housing
(Really ... I'm not kidding ...)

it uses a Radioshack 276-170 breadboard so you dont need to etch a board


************************************************** ****

This is the description for the Voltage Monitor.

The monitor is based on a pair of LM3914 Chips and a pair of
10-LED "bargraphs"
(like those sequential LED "power" displays that are on stereo amps and
tapedecks)

I used 2 of each for a 20 segment display, but you could use only 1 of
each for a 10 segment display or lots of each for an N-times-10 segment
display

The upper and lower endpoints of the displays can be adjusted to
indicate anywhere between about 8 and over 20 volts or so.

You can get the data-sheet for the LM3914 at

http://www.jameco.com/Jameco/Products/ProdDS/24230.pdf

The 3914 is pretty easy to use, and the monitor is more or less right
off the datasheet ...

The picture is the layout, and it is so simple, I didn't even draw a
real schematic.

it uses a Radioshack 276-170 breadboard so you dont need to etch a board

Jameco part#s are

300003CK 2 LM-3914
334529CK 2 LED Bar (Red)
334511CK 2 LED Bar (Green)(alternate to above ... pick your favorite color)
330798CK 1 10uf electrolytic
25523CK 3 .1uf ceramic chip (bypass)
41822CK 2 10K 15-TURN POT
41873CK 1 20K 15-TURN POT
Assorted resistors

an explanation of how it all works:

----------

The LED displays are at the top of the board.
Only the cathodes of the LEDs are soldered into the breadboard, where
they connect to the LM3914s.
The LED assemblys are then bent almost 90 degrees so that they can be
seen when the board is seen edge on from the bottom (see pictures)
This makes your display 1 inch high and 3 inches deep (and 3 inches wide)
All the anodes are then connected to a hookup wire which is connected to
V+ (see picture) (actually, I divided mine into 3 sections ...
electrically the same thing, but mechanically stronger)

Instead of bending the LEDs, you _COULD_ just solder the anodes directly
to the board at V+ (you would need to drill 3 holes), but then your
display would be 3 inches high and an inch deep (and 3 inches wide)
(I.E. it would not mount on the bike as well)

---

In the middle of the board are the 2 LM3914s and the associated
circuitry.

Each LM3914 has resistors connected to Ref-out and Ref-adj to set the
LED current and the voltage refrence.
(LM3914-1's Ref-out is not actually used, but is programed anyway so that
it roughly tracks LM3914-2's Ref-out)
Please note that the resistor values for LM3914-1 and LM3914-2 are
different.
(since those for LM3914-2 also account for the current drawn by the
internal divider chain)

There are also resistors connecting pins 9 and 11 of LM3914-1 to V+
which are required for proper daisy-chaining

---

On the bottom left corner are four 22k resistors.
(I think I may have changed these to 10k in the end, to make the LEDS a
bit brighter)
These connect ground to the cathode of four of the LEDs in order to
dimmly illuminate these LEDs at all times. The purpose of this is to
give a sense of edges of the display when it is dark outside. Kind of
like "background illumination". You could eliminate any or all of them
if you wish (or add more ...) The only requirement is not to connect to
LED 9 of the first 3914 or LED 1 on the second, since that would screw
up the daisy-chaining. When the 3914s illuminate one of these four LEDS,
they just add to the resistor's current, and swamp it. These LEDs are
shown in a lighter color in the layout for refrence. This idea is not
shown in the LM3914 datasheets

---

The caps are all just for bypass. A 10uf electrolytic and .1uf chip
where power comes on the board, and one more .1uf at each IC.

Thats probably way overkill, the first 2 are probably enough...
(and its possible that you could get away with no bypass anywhere at all)
But the caps are cheap, its recomended practice, and I'd rather not
track down oscillation problems because I tried to save 10 cents on a
cap.

---

On the far right are 3 multiturn pots. These set the high and low
settings for the Displays.

The rightmost pot is just a voltage divider between V+ and ground.
Its center terminal goes to the inputs of the LM3914s.
It is primarily used to set the voltage for LED 10 of the 2nd LM3914.
The other 2 pots do not have _MUCH_ influence on LED 10 of the 2nd LM3914.

The middle and left pots parallel the internal voltage dividers on
LM3914-2 and LM3914-1 respectively. The high side of the divider on
LM3914-2 is connected to the REF-out pin, and the low side of the
divider on LM3914-1 is connected to ground via a 10k resistor.
Thus the internal dividers and this 10k resistor form a 3 part voltage
divider which divides the ref-out voltage.
Since you can adjust the effective resistance of the internal dividers
with the parallel potentiometers, you can adjust the relative
proportions of the 3 part divider.

So you can adjust LED 10 of the 1st LM3914 (and LED 1 of the 2nd LM3914)
with the middle pot, and LED 1 of the 1st LM3914 with the left pot

Unfortunately, the other pots also interact with each of these settings,
so you have to iterate to get the settings correct...

You will need an adjustable powersupply to adjust the pots
It could be as simple as an LM317 (with a resistor and a pot)

http://www.jameco.com/Jameco/Products/ProdDS/23579.pdf

and two 9-volt batteries.

The setting procedure is as follows:

1) set the supply to the desired voltage for LED 10 on the 2nd LM3914
(for example 15 volts)
2) adjust the right pot till LED 10 on the 2nd LM3914 illuminates

3) set the supply to the desired voltage for LED 10 on the 1st LM3914
(for example 14 volts)
4) adjust the middle pot till LED 10 on the 1st LM3914 illuminates

5) set the supply to the desired voltage for LED 1 on the 1st LM3914
(for example 10 volts)
6) adjust the left pot till LED 1 on the 1st LM3914 illuminates

goto step 1 and repeat
(continue repeating until no more adjustments are needed in any step)

[pete]

Awesome, thanks Martin!

I've dumped the text and bitmap into a document so I can follow at my leasure.

I'm going to be getting some LED's for my guages soon so I'll get these bits and pieces at the same time.

This will give me something to do while I wait until I can budget for my exhaust and things.

And if you find those pic's, that will help me visualise it properly too, duct tape and all

Not sure if you saw it, but my exhaust mock up is cardboard...

[bakalorz]

Awesome, thanks Martin!

I've dumped the text and bitmap into a document so I can follow at my leasure.

I'm going to be getting some LED's for my guages soon so I'll get these bits and pieces at the same time.

This will give me something to do while I wait until I can budget for my exhaust and things.

And if you find those pic's, that will help me visualise it properly too, duct tape and all

Not sure if you saw it, but my exhaust mock up is cardboard...

The unit as built

[bakalorz]

Awesome, thanks Martin!

I've dumped the text and bitmap into a document so I can follow at my leasure.

I'm going to be getting some LED's for my guages soon so I'll get these bits and pieces at the same time.

This will give me something to do while I wait until I can budget for my exhaust and things.

And if you find those pic's, that will help me visualise it properly too, duct tape and all

Not sure if you saw it, but my exhaust mock up is cardboard...

on the bike installed in shock absorbing honeycomb cellulose based material, fastened using redundant elastic structural materials

this is not a mock-up ... this is the actual installation ... can you say ratbike ...

[bakalorz]

this is not a mock-up ... this is the actual installation ... can you say ratbike ...

Although to make it look "better" I eventually did use a black magic marker to make the cardboard black ...

[pete]

Hahaha that's awesome! Did you ever end up doing something more permanent?

I like the idea and I have two ten LED displays from years ago but they're done with the LED's aligned lengthwise together so they're a lot longer than the ones you've used there.

I'm thinking maybe a small modification with some rolled up ribbon cable to get the LED's away from the circuit board and allow for a much neater integration maybe to the bottom of the gauges.

Probably be a week or two before I get to order anything, but I've got some other stuff to do in the meantime as well like painting the brake calliper and the carbs etc.

I'll have some of the components already, but I'll need to work out what I'm missing so I can have everything on hand ready to roll.

[bakalorz]

Hahaha that's awesome! Did you ever end up doing something more permanent?

I like the idea and I have two ten LED displays from years ago but they're done with the LED's aligned lengthwise together so they're a lot longer than the ones you've used there.

I'm thinking maybe a small modification with some rolled up ribbon cable to get the LED's away from the circuit board and allow for a much neater integration maybe to the bottom of the gauges.

Probably be a week or two before I get to order anything, but I've got some other stuff to do in the meantime as well like painting the brake calliper and the carbs etc.

I'll have some of the components already, but I'll need to work out what I'm missing so I can have everything on hand ready to roll.

I actually took it off the bike to make a more permanent enclosure but then blew it up ... I was going to check the calibration ... the PDF mentions that the inputs are protected against up to +/- 40 volts ... I misremembered it as the entire chip being safe against +/- 40v. So when I went to check the cal, I didn't check polarity ... figured if it didn't work I would just swap the wires around ... I let the magic smoke out ... OOPS

I don't know how much the ribbon cable would get you. Using those LEDs, the faceprint is pretty much determined by the LEDs as 2 inches wide by 1/2 inch tall ... if you don't care about depth, you can easily hide everything behind the LEDS if you go back 2 or 3 inches.
If you are willing to etch boards and hand solder surface-mount stuff (not that tough) you could reduce the depth by at least an inch too.

I guess that ribbon would let you make the depth only 1/2 an inch though, if you want to stick it on the surface of something. But you would have to route the ribbon cable, and it doesn't really bend or smoosh very well ...

when I redo mine I'll try to set it up so its only 2.1 inches wide, with everything behind the LEDs on an etched board.

[Matchless]

Pete,
I once made a voltage monitor, but found the flickering of the LED's a bit distracting.
Someone told me to rather design it only using a low voltage and over voltage indication. Meaning that when the voltage was correct no LED's will be on.
Thus when you switch the bike on the led will be say yellow for <13 Volts and when it say goes to >15 Volts it shows red. When you see no lights, its charging OK.
I never did this and just went for an analogue meter in the end.

[pete]

I actually took it off the bike to make a more permanent enclosure but then blew it up ... I was going to check the calibration ... the PDF mentions that the inputs are protected against up to +/- 40 volts ... I misremembered it as the entire chip being safe against +/- 40v. So when I went to check the cal, I didn't check polarity ... figured if it didn't work I would just swap the wires around ... I let the magic smoke out ... OOPS

I don't know how much the ribbon cable would get you. Using those LEDs, the faceprint is pretty much determined by the LEDs as 2 inches wide by 1/2 inch tall ... if you don't care about depth, you can easily hide everything behind the LEDS if you go back 2 or 3 inches.
If you are willing to etch boards and hand solder surface-mount stuff (not that tough) you could reduce the depth by at least an inch too.

I guess that ribbon would let you make the depth only 1/2 an inch though, if you want to stick it on the surface of something. But you would have to route the ribbon cable, and it doesn't really bend or smoosh very well ...

when I redo mine I'll try to set it up so its only 2.1 inches wide, with everything behind the LEDs on an etched board.

Ooops! Sounds like something I'd do actually

The LED bars I have are probably 2 1/2 to 3 inches wide as the LED's are the opposite orientation to yours, so I was thinking of putting them on the bottom of the gauges, however I just realised that there's a cutout for the ignition switch, but maybe I could mount individual ones along the edge? It'd be a bit tedious but definitely doable and it would integrate it nicely with the gauges too.



Good point on the ribbon cable, although I could probably run it just for an inch or so and have the box mounted under the gauges depending on headlight clearance.

[pete]

Pete,
I once made a voltage monitor, but found the flickering of the LED's a bit distracting.
Someone told me to rather design it only using a low voltage and over voltage indication. Meaning that when the voltage was correct no LED's will be on.
Thus when you switch the bike on the led will be say yellow for <13 Volts and when it say goes to >15 Volts it shows red. When you see no lights, its charging OK.
I never did this and just went for an analogue meter in the end.

I get what you mean Andre.

I don't think that will be an issue for me, although I guess I won't know until I try it.

I think if I integrate it into the gauges well enough, then it won't be a distraction.

[pete]

I ordered the bits and pieces (minus the LED's) yesterday morning for this as I have very little aside from this that I can work on at the moment.

[Bill Alexander]

These LED type meters are useless to me and anyone else who is colour blind. Greem/red/orange...... bahh... all the same to me.

I am wondering if anyone else has thought of using a digital volt meter ? I purchased a very basic Digital Panel meter which measures DC volt frm 8 to 30. It is about 25 x 50mm and sits quite nicely on top of the instrument pod (at the moment I am just using velcro dots but may look at doing something more permanent).

It cost $30 at JayCar (our Aussie mates should be familiar with them) and just had to have 2 wires connected - can't even get them backwards because polarity is automatically sensed. I connected to the orange wire out of the ignition for + and one of the indicator earths for -. Comes on with the ignition and gives me a nice little constant display of the voltage. If any one is interested I will try and remember to get a photo to post.