TK's Emisar D4 review

[hIKARInoob]

@BeardedRaleigh

@winspiration

Can this take Olight batteries?

I would stick with unprotected flat tops. Keep your springs in good shape.

Yes. I’m using button top GA now, but definitely prefer, and feels better using a flat top cell.

[djozz]

@BeardedRaleigh

Yikes let’s keep it PG.

LOL, ignorant me did not intend my remark that way, I will remove it!

[winspiration]

@BeardedRaleigh

@winspiration

Can this take Olight batteries?

I would stick with unprotected flat tops. Keep your springs in good shape.

Isn’t protected safer though?

[hIKARInoob]

@winspiration

@BeardedRaleigh

@winspiration

Can this take Olight batteries?

I would stick with unprotected flat tops. Keep your springs in good shape.

Isn’t protected safer though?

Generally yes, but protected cells often don’t work in a light like the D4. There are two reasons:

1) It just doesn’t physically fit. Either it’s too thick, and/or it’s too long due to the protection circuit. The D4 probably won’t contact when tightening the tailcap.
2) 99% of protected cells are going to trip most likely due to the current that’s too high. Only recently you have 15A protected cells; those might work… if they fit… But they probably don’t fit anyway.

[BeardedRaleigh]

@djozz

@BeardedRaleigh

Yikes let’s keep it PG.

LOL, ignorant me did not intend my remark that way, I will remove it!

Haha. I figured. I had to say it still. Lol.

[charles_lin]

Finally, I receive 18500 tube from intl-outdoor. I like it better than 18350, Tiny size but still have enough length for nice grip! Too bad, there is no good 18500 battery on market right now .

(WB 5000K): XP-G2 3D, Nichia 219c, XPL-HI 3A

[ToyKeeper]

@Agro

Played a bit with thermal regulation.
It’s less smooth than I expected, the output stays visually stable, makes a jump, stays stable for another while, jumps again etc.
Also, I noticed that if I heat it up a bit, turn it off and start at full output, the peak temperature will be much higher than originally. Also, I think it may be exceeding the level that I configured….or maybe my burnt fingers got more sensitive

It can drop down in large steps. Stepping back up only goes one small step at a time though.

The step-downs could be made smoother with a bit more code, but it also has a high risk of introducing bugs. I actually tried it at one point, but the direct approach was too buggy and the indirect approach was fragile. So I went with a more robust but also more visible method.

Also, the regulation is not based on the current temperature, but on the predicted future temperature. This means it’s sensitive to the rate of change. If it’s below the target temperature but rising quickly, it will step down pretty quickly. But if it’s above the target temperature and falling quickly, it won’t step down (and may even step up a little).

When it first turns on in turbo, it will generally exceed the target temperature before it stabilizes. This is because, even with the predictive algorithm, thermal lag still delays the measurements too much to avoid the initial peak. Basically, thermal regulation is rather unpleasantly like trying to steer a fast-moving cow around a hairpin turn on an icy race track. While wearing someone else’s glasses.

@hIKARInoob

Edit:

The higher the temperature increase rate (dT/dt), the bigger the difference between desired maximum temperature (what you felt), and actual max temperature value (Tmax set by D4).

Yes, it’s based on the predicted temperature, not the current temperature. This helps it compensate for thermal lag. Without that, the racing cow was slamming into each turn’s crash wall a lot harder.

@Agro

2. I noticed a quirk in the UI. If I ramp the light up to a fairly high level, wait for thermal management to restrain it an start ramping again, I expect the light to smoothly change output. It jumps to the previously set level and starts ramping from that.

The light makes a distinction between the actual ramp level and the target level. The button sets the target level, while thermal regulation can change only the actual level. This allows it to step back up when the actual level is lower than the target level and the temperature is no longer too high.

To change the behavior, the ramp button code could perhaps use the actual level instead of target level, when they’re different? I doubt it would be a difficult change… and patches are welcome.

@Agro

3. A weird software bug:
   Sometimes the light doesn’t notice that I cut off the power.

If I understand correctly, this isn’t a software bug. It means the power wasn’t disconnected long enough for the driver to lose power. To make this happen, do the following:

• Ramp to a low level.
• Click to turn the light off.
• Wait at least 6 seconds so the light will enter sleep mode.
• Loosen then tighten the tailcap quickly.
• Notice that the light doesn’t blink. Click to turn it on, and see it’s still at the last-used level.

This happens because the standby current is so low that it is able to tolerate short interruptions while it’s asleep.

[ToyKeeper]

@djozz

USB charging.

I wonder how hard it would be to add an inductive charging circuit in a tailcap. I really don’t like poking holes in a waterproof light for USB ports.

Not that I have an inductive charger… but it might be a nice way to do these things without incurring the usual problems associated with built-in charging.

[Fuzzylogic]

@charles lin

…

Can I ask what clips you are using here? They seem to be a much better length than the convoy ones.

[ToyKeeper]

@KawiBoy1428

This reminded me I have a bottle of GitD paint. I still haven’t decided what to do with it.

[ToyKeeper]

@RollerBoySE

Is a zero shown as something similar to half a blink?

Yes. That was one of the things I fixed. Before, ‘0’ digits weren’t shown at all.

[hank]

the regulation is not based on the current temperature, but on the predicted future temperature. This means it’s sensitive to the rate of change.

This is just amazingly smart. Thank you.

[Slayer1]

Thanks again KawiBoy1428!!. Cheers.

[electricjelly]

I received my Emisar D4 in the nichia flavor today. I’m loving it. Thank you Tom E and Toykeeper for nailing the ramping UI. Thank you Hank Wang for bringing this light to market. The quality is top notch and the price is an amazing value. I have another one on its way with the xp-g2 5D tint. I love all the choices available. I had been wanting a Zebralight SC62-3 but this light has scratched that itch for sure. Good job to everyone involved.

[Agro]

@ToyKeeper

@Agro

2. I noticed a quirk in the UI. If I ramp the light up to a fairly high level, wait for thermal management to restrain it an start ramping again, I expect the light to smoothly change output. It jumps to the previously set level and starts ramping from that.

The light makes a distinction between the actual ramp level and the target level. The button sets the target level, while thermal regulation can change only the actual level. This allows it to step back up when the actual level is lower than the target level and the temperature is no longer too high.

To change the behavior, the ramp button code could perhaps use the actual level instead of target level, when they’re different? I doubt it would be a difficult change… and patches are welcome.

I would be happy to produce such patch, but so far I don’t have a way of flashing the patched firmware and so I can’t test it. Developers seem to move away from SOIC8 chips, so investing in a SOIC8 setup at this moment doesn’t seem like a good idea….

@ToyKeeper

@Agro

3. A weird software bug:
   Sometimes the light doesn’t notice that I cut off the power.

If I understand correctly, this isn’t a software bug. It means the power wasn’t disconnected long enough for the driver to lose power. To make this happen, do the following:

• Ramp to a low level.
• Click to turn the light off.
• Wait at least 6 seconds so the light will enter sleep mode.
• Loosen then tighten the tailcap quickly.
• Notice that the light doesn’t blink. Click to turn it on, and see it’s still at the last-used level.

This happens because the standby current is so low that it is able to tolerate short interruptions while it’s asleep.

Confirmed, I can reproduce it with your steps. Why doesn’t it happen every time after a power-reset?

[Ronin42]

TK you have just won the best line in August award.

I cant decide which:

1. “When it first turns on in turbo, it will generally exceed the target temperature before it stabilizes. This is because, even with the predictive algorithm, thermal lag still delays the measurements too much to avoid the initial peak. Basically, thermal regulation is rather unpleasantly like trying to steer a fast-moving cow around a hairpin turn on an icy race track. While wearing someone else’s glasses.”

LOL

2. “Basically, thermal regulation is rather unpleasantly like trying to steer a fast-moving cow around a hairpin turn on an icy race track. While wearing someone else’s glasses.”

LMFAO

And for the rest of us I think you just made a 4th gen light (we don’t actually control it) we give it our input and then it decides the exact output. sounds about right, maybe like modern high performance aircraft we can’t react fast enough.

All Hail TK and her Fly by Wire flashlights! Were not worthy

[electricjelly]

I’d love to see a Emisar 90 degree angle headlight.

[Agro]

I have another usability comment…
I’d prefer the light not to remember the ramping direction for too long. Myself, I forget it seconds after I stop ramping. After that I never know what will the light do if I start ramping again.

[ven]

@electricjelly

I’d love to see a Emisar 90 degree angle headlight.

Hot head!!!

[BeardedRaleigh]

@electricjelly

I’d love to see a Emisar 90 degree angle headlight.

I have always wondered why we have to have the light on our forehead? Why can’t we just use a regular flashlight on the side?

I don’t care either way, just sayin.