touch sensor USB rechargeable Nicostick

[caesar]

Ladies and gentlemen, same features as my previous mod, but now is fired by a touch sensor. No moving parts, no failures.

Thanks for inspiration goes out to Nicowolf, mogur, kinabaloo and all the fine members of this forum.

Runs on a Li-Ion 14500 900mAh AA battery, charger is onboard, drawing a maximum of 500mA from the USB port, standard mini-USB connector.


Have fun with the pictures and movie

YouTube - touch sensor USB rechargeable DSE-901 NicoStick

 

[TnA]

Beautiful work, caesar! That PCB looks good!

 

[caesar]

Thanks, this version is completely SMD based but on the old PCB layout.
I can shrink it around 18mm in lenght so a 801 atty can be almost fully inserted.

 

[warp1900]

That is just incredible caesar, you made the nicostick a pro mod at all levels. The JS was left behind in the dust!

Hope to see more mods from you in the future.

 

[caesar]

Thanks warp. Don't forget it's RCA plug friendly

 

[warp1900]

Thanks warp. Don't forget it's RCA plug friendly

It sure is, and I'm already reading and trying to learn on how to make PCBs, since you posted this the first time.

 

[caesar]

The toner-photo paper method is working great for me. I am able to do perfect 0.25mm traces. Collecting all unused portions into the ground plane helps a lot.

 

[kinabaloo]

Nicely done caesar !

Neat work with the PCB

Are those staples for the contact? A good choice of arrangement anyhow - close together and finger width; should work well even in dry conditions.

 

[caesar]

Indeed, staples they are, the smaller variety.

You can even touch them with different hands and still work actually. I really found a winning combination.

I found myself a new hobby besides PIC microcontrollers: MOSFETs

kinabaloo, is it just my impression or are mosfets relly firing the attys better then manual switches?
It seems that the same battery and atty produce a whole lot more vapor on a mosfet then on a platinum plated good quality manual switch.

 

[crazyhorse]

Where can a garden-variety hillbilly get a touch sensor switch? Ratshack momentary switches are getting old in a hurry

 

[Nforcer]

Completely awesome piece of engineering u have created Caesar .. Good job! Way outrunning the Janty stick

 

[joedirt]

kinabaloo, is it just my impression or are mosfets relly firing the attys better then manual switches?
It seems that the same battery and atty produce a whole lot more vapor on a mosfet then on a platinum plated good quality manual switch.

No, the Rds of the mosfet is gonna be higher then any decent switch. It could be using less wiring, so maybe all those tiny wires are the problem when dealing with 1A. The auto batteries use a mosfet just FYI.

 

[joedirt]

Regarding current control.. and the "temp profile" idea.

One issue I've come to discover is that for a dry NiCr, then yes, temp is proportional to current. However, imagine a heater you plunk in a pot of water. You can keep increasing the current which delivers more power, but the real temperature of the water always stays at the boiling point. Also the temp of the coil is much hotter then the surrounding wicking silica. So a current measuring won't detect a dry or wet wick... and possibly not air flow.

As much as I hate the auto batteries, I think the idea of the air sensing is important for battery life and atty life... But possibly not as implemented in the auto batteries.

Two improvements I've been thinking about are fuel injection type system and also the concept of a mass airflow sensor from cars.

Anyways, the best current control I've seen for this application appears to be a DC-DC converter (buck or boost depending on 3.7 or 7.4V). They are pretty efficient and the current control can be set in some of these. Also some LiIon charging chips appear to have adj. current for charging and might be able to be used.

Finally, does anyone have an analog current meter, or osc to do this experiment... Measure the current to the atty no air for 1 sec, then normal puff for 3 sec, then hard puff for 3 sec. Just to see if the current even changes. I don't think it will change if you have a monster battery, but possibly with a smaller battery it might not be able to "keep up"...

 

[Wingnut19]

Gotta be the nicest mod I've seen! nice work.

 

[caesar]

No, the Rds of the mosfet is gonna be higher then any decent switch. It could be using less wiring, so maybe all those tiny wires are the problem when dealing with 1A. The auto batteries use a mosfet just FYI.

I have no equipment to measure such low resistances. The Rds of the mosfet is 40microOhms @ 3.5V Vgs (taken from datasheet).

I am comparing it to a good quality 5A platinum plated limiter switch and with every atty, same battery and same juice, the vapor amount is visibly and notably higher with the mosfet then the switch.

Tested other cheap switches too and they are fairing even worse.


Regarding the temp profile, there is no method to sense the current that I know of that doesn't add more load to the circuit. For me it's a no-go even with a 900mA battery.
I personally think it's better to tune it by watching the atty perform then by draining the battery more. That is a talk for the future and still open to debate.
Right now I don't have the time to physically work in that direction.

This mod is particularly good working so I'm finally feeling confident with it and use it all day long. The 901 is draining the batt at 1.1C (970mA as real battery capacity tested out at 880mA) so I also expect a very long and prosperous battery life considering it is charged at 0,5C using a dedicated chip.

 

[SmokinScott]

Caesar this goes beyond modding, and into the realm of prototyping!
Excellent job!

 

[cybervex]

Any interest in posting a parts list? Possibly a "How to" thread.

 

[Nforcer]

Any interest in posting a parts list? Possibly a "How to" thread.

That would be nice ... lets hear it

 

[kinabaloo]

Indeed, staples they are, the smaller variety.

You can even touch them with different hands and still work actually. I really found a winning combination.

I found myself a new hobby besides PIC microcontrollers: MOSFETs

kinabaloo, is it just my impression or are mosfets relly firing the attys better then manual switches?
It seems that the same battery and atty produce a whole lot more vapor on a mosfet then on a platinum plated good quality manual switch.

Hi Caesar, sorry - missed your post until just now.

I noticed that too. A contact switch cannot go much below 0.2ohms (best i could tell with a multimeter) whereas a mosfet would likely be well under 0.02 ohms. So a switch might lose around 0.2v, not huge, but noticeable (this figure probably has a wide variation).

 

[Moobyghost]

<---- DO want! lol.