New Convoy C8 – Clearly better

Please contact Simon through the store. I’ll mention it to him as well but I know he will want you to contact him directly. This is the first issue I’ve heard of but this is all completely new. Hopefully it’s just a fluke. Any problems will be resolved properly I’m sure. Simon would not ask you to “live with it”.

Well said ‘gchart’……. :+1:

Good news, seems like it might in fact be a fluke. Just did a quick test of my 2nd new C8 that I had left at the office, and it doesn’t show that behavior at all. Moonlight seems to work just fine on my 2nd one. :slight_smile:

That is good news!!! :+1:

In all the hundreds of drivers I’ve built using the ATTiny13A MCU, I finally got one that glitched. It “shifted gears” unreliably, randomly, with no rhyme or reason. Built a new one, next MCU out of the sleeve, works fine. So apparently there are random fluctuations in the components that allow for slight differences and this sometimes trips us up when we’re using parameters that are right at the edge to begin with. :wink:

I also once got a driver from a known high quality dealer that had a sense resistor glitch. Even the little simple sense resistors can seemingly be off by a significant margin once in a while. It’s been said before, if something CAN go wrong, it’s gonna find ME! :stuck_out_tongue:

Thanks for the update, gentlemen. Glad it seems to be an isolated event.

And my apologies for calling TK’s code into question earlier. I was wrongly assuming that what was published on launchpad would be the same as what she sent over to Simon. :person_facepalming:

FWIW and until TK comments, PWM of 1/255 should work fine with this firmware.

(IIRC the PWM frequency is adapted to the mode: Lower frequency for lower modes. So the 7135s actually have time to consistently turn on fully even with very low PWM values.)

Biscotti firmware works fine on all my flashlights with 6*7135 and 8*7135 drivers (s2+, s3, c8, old MTE with P7 led)

You may be onto something here. As I said, I haven't actually flashed Biscotti onto anything yet, so I haven't a clue. But Biscotti does adjust the prescaler and between Fast & Phase for the lower modes, so it very well could work with a PWM value of 1/255.

Edit: removed some misinformation to hopefully avoid confusion.

Level here is a number of element in RAMP_FET array. So all works correct.

Ugh, good call. Serves me right for posting to forums while at work… read thru the code too quickly :person_facepalming:

Naw, I mentioned that issue (questioned about it, actually) back in msg #81 here. It’s a fairly well-known issue, or so I thought. :slight_smile:

I think the problem is that when you’re parallelling 8 7135s, having to power up each one at once, all from a single µC’s output pin, there’s just a limited supply of current that pin can source, so the “capacitance” of all of them taken together needs time to “charge up” to +V, and if the width of that pulse is just too narrow/short, and that bank of 7135s “charges up” just too slowly, well, nothing happens.

If the bank of 7135s needs 2 pulses to get going, with a pulse-width of 125 counts, they’ll see 123 pulses worth of power. 81 pulses, they’ll see 79. 23, they’ll see 21. 5, they’ll see 3. 1, they’ll see… 0!

Not quite exactly accurate, but a reasonable facsimile of what’s happening.

Oh, sorry, and that’s why limiting the number of 7135s (eg, 6 vs 8) can help. If you only need 1.4A of power, better to use 100% at 1.4A vs 50% of 2.8A.

For a given lumen output, if moonlight would be a pulse-width of 2 at 2.8A, it could afford to be 4 at 1.4A.

And try 3, see if that’s reliable, and you’ll have an even lower moonlight mode (vs 4) with the 1.4A driver than with the 2.8A driver.

I know I announced the new firmware in this thread as the clear anodized C8 was the first to use the new driver/new firmware. That’s my bad. :zipper_mouth_face:

Would it be reasonable to ask that the driver firmware specific questions/discussion move to ToyKeeper’s firmware repository thread?

My main reason in asking this is that the questions and issues being discussed will be more easily addressed by those participating in that thread and also much more likely to be seen by the creator of this firmware. ToyKeeper did me and Convoy a huge favor by creating this and I feel she should be given the opportunity to respond to questions about her creation without having to try to keep up with this thread.

ToyKeeper’s thread about the firmware she develops is here.

I don’t even understand half of what is being discussed now :person_facepalming: so I assume many of the people that are just coming to this thread to read about the new light will be completely lost.

If you think I’m off base here please tell me so. I do appreciate all this discussion and like I said this is almost certainly my own doing but it feels weird to be a confused passenger in my own topic wondering where the bus will stop next… :blush:

I’m with you JDub, the firmware stuff while interesting reading, is better served being split out.

I’ll now go back and just keep waiting for someone to post beamshots of this thing in this thread

Sure, go crazy…

I’m not sure how to “forward” a message to a different thread, so I’ll leave it to all y’all to figure out how to do that. :smiley:

And I wasn’t making any complaint or anything, just (initially) asking if anyone noticed that problem, and (now) trying to explain what’s probably happening. Wanted to make that explicit.

(It’s actually something of a hardware issue, too, so the firmware’s not really to blame. It’s an “edge” condition.)

Any news?

Just that it’s getting closer. The original design was quite good but more on the generic side. The new design will still be fairly universal in application but will have a more distinct Convoy look. The factory has a prototype and I think we should see production reasonably soon. I promise I will post the info when I can.

I’d love to try out this new driver however, I do not like that I have to go through STROBE before getting to biking mode and battery checker mode. I’m not a fan of strobe on a bike light. ;/

Got a USBASP AVR programmer and SOIC clip? If so, you could either tweak Biscotti or one of us could do it for you… you’d just need to flash it. If you’re interested, either hit me up on PM or head over to TK’s firmware thread.