Issue with cresendo or driver need some help

Flashlight Modding and DIY Parts
1

I built a convoy s2+ with cresendo

I used a MTN 17 DDM driver from mtn electronics

The issue for me is that the double tap and triple tap does nothing for me but turns off the led, light seems to be on since a single tap gets it ramping up again. It doesnt seem to ramp to 100 % on the top of the ramp(?)
No flickering and turns on fine, but im really scratching my head right now trying to figure this out, hopefully someone here knows what could be the culprit.

Regards

2

So the driver was bought from MtnE with Crescendo firmware pre-flashed.

You are saying that with the light turned ON and in a STEADY state, a double tap turns the light OFF instead of beginning to ramp in the down direction?

And that with the light turned ON and in a STEADY state, a triple tap turns the light OFF instead of giving instant Turbo Mode?

If you are not mis-tapping and actually clicking the switch to OFF, then there must be something wrong. At least that is what it seems to me.

Disclaimer: I have not bought any Crescendo equipped drivers but I have a light I flashed with Crescendo myself right here as I type.

I assume you have seen the UI diagram.

3

Hopefully someone here can shine some light, and has some sort of resolution, i really need the turbo to work, without the shortcut it fabricates this light useless for me.

Q: So the driver was bought from MtnE with Crescendo firmware pre-flashed.
A: Yes

Q: You are saying that with the light turned ON and in a STEADY state, a double tap turns the light OFF instead of beginning to ramp in the down direction?
A: No, ramping works correctly, the turbo and strobe seem to turn of the led but it remains in STEADY state.

Q: And that with the light turned ON and in a STEADY state, a triple tap turns the light OFF instead of giving instant Turbo Mode?
A: Yes

(tap = half press)

.
From OFF:
(memory off) 1 full click = on at moon level and begins ramping
(memory on) 1 full click = on at memorized level and remains steady
1 full click then Single tap = Moon
1 full click then double tap = Turbo Does not work
1 full click then triple tap = Strobe / Batt check / Special modes Does not work

.
From ON (while ramping):
Single tap = pause ramping (steady on at the level when tapped)
1 full click = OFF

.
From ON (after pause ramping):
Single tap = resume ramping UP
Double tap = resume ramping DOWN
Triple tap = Turbo Does not work
Quad tap = Strobe / Batt check / Special modes Does not work
1 full click = OFF

.
From Moon:
Single tap = begin ramping
Triple tap = Turbo Does not work
1 full click = OFF

.
From Turbo: Does not work
Single tap = back to steady on at previous level
1 full click = OFF

4

That does seem perplexing. I have flashed crescendo on several lights and I recall getting some weird behavior in rare instances. I believe the behavior was intermittent because I can’t recall doing anything to fix it and all the lights work now.

My memory about those problems has faded, but I speculated they had something to do with how crescendo measures the timing of the taps. Instead of using an off-time capacitor like lots of other FWs it uses something with how some memory bits in the MCU decay over time. I obviously don’t understand it so if someone can explain better it I would appreciate it.

Just so we have all the info, what LED and battery are you using in the light? When you say it doesn’t reach 100% brightness: it should do a little blink when it reaches the top of the ramp. Does it not do that?

Worst case I think mtnelectronics would replace it if it’s not working right. I agree that triple tap to turbo is a great feature of the UI.

5

What would you guess the max brightness was, compared to another light.

I am leaning towards NO FET

EDIT— from TURBO (no output) you can ramp down to lower outputs.
EDIT— seams odd that the bat check would be on the fet tho

6

That’s a good idea chadvone. It does fit some of the symptoms.

7

With “off time” clicky lights the MCU is reset and restarted on every single button press, and all “normal” data in memory is reset (initialized) too. However, if the data has the attribute “no init” it doesn’t get reset, what ever is there is there. With certain parameters set, this data can survive a short off press. If off press is too long it decays.

I believe this is the first post of this being mentioned, read the “original post” part: alexvh's firmware. Update: Hidden strobe, Ramping and optional mode memory added.

8

Is this FET+7135?

I’d say the FET is dead.