Jump to content
Sign in to follow this  
bweight

Nav Lights problem

Recommended Posts

Hi, I'm new to the forum and I've been working feverishly on your Nav-light project posted here on your site.. Now, I've never done this type of thing before, but I know it's fairly straight forward... (or so I would think :D )

Anyways, I've programmed the PIC chip I believe.. All the errors that you said will happen, did, however, I have no clue whether it did or not.

I have no clue how to make the printed PCB's so I'm using standard perfboard from Radio shack, and making a nice mess with the wires underneath. I lost myself with the wires for a bit, but I re-looked over everything tonight and I noticed a few things were out of order so I fixed that.

Here are the problems I'm running into..

1. Determining values for LED Resistors.. I am using 20mA Superbright LED's that I purchased... I've used your calculator, and I think the value came out to something like 80.. it was below 100ohms.. Does this mean I *have* to use that rating of a resistor or can I go over that? If I go over that, do I risk lowering the intensity of the LED?

2. Upon plugging in J1 and J2 to their respective spots, I noticed that the LED status light stayed off.. Which is good from reading the instructions. Next, I had full range of motion on my Throttle servo connected to the circuit, so I assume that I've got that setup correctly. However, the LED strobe (so far the only one I have completed the circuit on) did not blink, blip, turn on, or anything. I checked over the wires again, but I think there's such a mass under there that it's easier, and less of a headache to start over.

Could someone please point me in the right direction and tell me whether getting the throttle to work, is a sign of a few wires out of place, or is that irrelevant to the PIC chip and it's programming in this situation. I have no idea to be quite frank.

I would really like to "etch" a PCB, but as I stated earlier, I just don't know how too..

Thanks in advance, for any and all assistance.

Brian

Share this post


Link to post
Share on other sites
1. Does this mean I *have* to use that rating of a resistor or can I go over that? If I go over that, do I risk lowering the intensity of the LED?
As you increase the resistor value you reduce the LED current. This lowers its brightness. Try to keep the LED current between 20mA and 25mA.

2. However, the LED strobe (so far the only one I have completed the circuit on) did not blink, blip, turn on, or anything.

That is a bad sign. It should blink. Also, the status LED should turn on if the R/C Tx is turned off (loss of signal detect).

Could someone please point me in the right direction and tell me whether getting the throttle to work, is a sign of a few wires out of place, or is that irrelevant to the PIC chip and it's programming in this situation.

Every function in this design, other than the right and left wingtip LED's, require that the PIC is functioning.

Troubleshooting:

1) Place the black lead of your voltmeter on PIC Pin 8 and the red lead on Pin 1. You should measure +5VDC.

2) Remove the PIC. Temporarily jump PIC socket pins 1 and 3. The status light should glow. Remove the jump.

3) Remove the PIC. Temporarily jump PIC socket pins 1 and 2. The landing light should glow. Remove the jump.

4) Remove the PIC. Temporarily jump PIC socket pins 1 and 5. The strobe light should glow. Remove the jump.

If all above is good, but the PIC does not do anything when installed, then the PIC is bad or not programmed.

Share this post


Link to post
Share on other sites
As you increase the resistor value you reduce the LED current. This lowers its brightness. Try to keep the LED current between 20mA and 25mA.

Ok, I'll have to re-check things.. I have a ton of resistors, just not sure on all their values..

That is a bad sign. It should blink. Also, the status LED should turn on if the R/C Tx is turned off (loss of signal detect).

I read that in the instructions part and it's troubling me. I think it's more the LED's wired incorrectly than them not producing a blink.. Like I said, I'm new to this stuff, and I'm still trying to learn what connects to what and in which direction. From what I can remember reading about the LED's is that the Cathode can be distinguished by the bigger "head" inside the LED tip.. Now, when looking at the schematic, which part of the symbol is the Cathode on there to connect with the Power, and which part goes to the portion of the circuit that has the Resistor and, Capacitor and Transistor wired up? (Long lead on the LED or the short one? - That's much easier for me to understand :D )

Every function in this design, other than the right and left wingtip LED's, require that the PIC is functioning.

Troubleshooting:

1) Place the black lead of your voltmeter on PIC Pin 8 and the red lead on Pin 1. You should measure +5VDC.

2) Remove the PIC. Temporarily jump PIC socket pins 1 and 3. The status light should glow. Remove the jump.

3) Remove the PIC. Temporarily jump PIC socket pins 1 and 2. The landing light should glow. Remove the jump.

4) Remove the PIC. Temporarily jump PIC socket pins 1 and 5. The strobe light should glow. Remove the jump.

If all above is good, but the PIC does not do anything when installed, then the PIC is bad or not programmed.

I'm at work now, but when I get home I'll try that out. Like I said, the Throttle servo works fine, and if I read what you're saying correctly, then the PIC is at least partially functioning..

Every function in this design, other than the right and left wingtip LED's, require that the PIC is functioning.

Is what you said regarding the PIC.. so yeah, I'm assuming it programmed somewhat correctly.

Now, if I was to take the PIC, plug it back into my programmer, and then just try to "read" the data, not burn, write, or verify... should it match up with the hex file that you posted for the navlights?

Thanks again for your help, and patience with an electrical noob :D

Share this post


Link to post
Share on other sites
Now, when looking at the schematic, which part of the symbol is the Cathode on there to connect with the Power...
The Cathode is the "banded" end. The Anode is the butt end of the arrow. In most cases, the anode is the long lead. The cathode is the flat area on the LED's body if it has a flat area. If in doubt, download the data sheet from the outfit you bought the part from and look at the provided drawing.

Now, if I was to take the PIC, plug it back into my programmer, and then just try to "read" the data, not burn, write, or verify... should it match up with the hex file that you posted for the navlights?
The code is protected. You cannot perform a verify after it is burned.

Like I said, the Throttle servo works fine, and if I read what you're saying correctly, then the PIC is at least partially functioning..
The throttle servo is NOT controlled by the PIC. If you look at the schematic, you will see that the throttle servo leads are shared with the Rx's cable (J1 & J2 are in parallel). So, the Rx controls the throttle servo, not the PIC.

Just perform the tests I suggested. If you end up starting from scratch, I suggest you build this in stages. Start with a minimum circuit: U1 (PIC), C1, J1 (Rx cable), and the strobe LED parts (R4, Q1, R1, C3, LED2). If the strobe is not working, then you have a simple circuit to troubleshoot. If the strobe blinks, add the next LED circuit that suits your fancy. Just build upon each success.

Share this post


Link to post
Share on other sites

Sorry to bother ya again.. I just need 1 more quick tip..

Looking at;

led.gif

Which end on there is the cathode and the anode?

Again, sorry for my ineptitude with this stuff, but hey, I'm learnin :)

Share this post


Link to post
Share on other sites

Ok.. well, here's an update on the progress..

I tried fixing the problem I had, and well, it was a lost cause, so I stripped the board down, and started on a new one. I *finally* got the status LED to at least light up with power on and the pins jumped (no PIC installed)..

So that's a good start. Next, I worked on the strobe. Carefully checking my work, to see if I crossed any joints or anything that could cause problems.. So I finished up the wiring on the strobe, and hooked power, jumping the pins again to test. This time, my superbright light up.. :D

I broke the soldering tip, and I could not continue anymore, so I took the tip to drop the PIC into the socket and give it a go.. Well, The status LED did not come in (good news), however, the strobe blipped briefly and VERY dim compared to the test I just ran.. Then, there was nothing from it. No strobe at all.. I had the servo hooked up, and I tried to set to 2 winks with the radio, to no avail..

I'm guessing now, that either the chip is bad, or it did not program successfully the first time. So, 2 more questions come from this :)

1. Can I try programming again, since if it did program, it'll be a dud anyways, but if it didn't and was a dud to begin with, then what the heck I say right?

2. Which other PIC can I use for this particular project? The 12c508a's are NOT easily accessible in a reasonable amount of time here at the local shop.. And are ridiculously overpriced as well.. I have another 12c508 that's still virgin, but if the problem continues, then I'm gonna have to get some more obviously.. I have a programmer and I've used the programs recommended on the info sheet that came with it, but I don't know if they're good or not..

Anyways, thanks again in advance for any assistance.. I know I'm gettin there, so it's just a matter of time before my Arrow flies with the lights :)

Share this post


Link to post
Share on other sites
1. Can I try programming again, since if it did program, it'll be a dud anyways, but if it didn't and was a dud to begin with, then what the heck I say right?

Sure, it is worth a try.

2. Which other PIC can I use for this particular project?

You can use a PIC12C509A. Don't forget, microchip.com will send you free samples if you request them on their web site. They ship these freebies by FedEx, to anywhere in the world, so you get them fast. And at no charge. :)

Share this post


Link to post
Share on other sites

Thanks again..

Just my luck, 508's and 509's are not offered as samples from their website :(

Oh well.. hopefully I'll be ok with the 2 that I have..

Share this post


Link to post
Share on other sites

Just wanted to thank you again for your help with this.. I rebuilt the entire system, found some new software for my programmer, and the system is complete and working flawlessly now. I just have to wait to finish up the plane to get it installed, but it's going to look great..

Thanks again.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×