[Tinkerphones] New tinkerphone gadgets in Goldelico shop?

H. Nikolaus Schaller hns at goldelico.com
Mon Nov 13 11:36:16 CET 2017

Hi Xavi,

> Am 13.11.2017 um 10:58 schrieb Xavi Drudis Ferran <xdrudis at tinet.cat>:
> El Mon, Nov 13, 2017 at 09:41:44AM +0100, H. Nikolaus Schaller deia:
>> I would like it as well!
> :) 
>> And I have a simple idea how to build one. I still use one of the original
>> GTA04A1 prototype boards where just some components were soldered on,
>> incl. the battery connector. I use it to power a GTA04 from battery
>> without covering the OMAP processor. It is not a charger (there is
>> no charger chip installed), but used as a power bank...
>> It looks like this (the board on the left is the GTA04A1):
> Good, possibly someone can design a ·D printed case or something, but it 
> would already be something. 

It works completely without case... In the spirit of tinkerers :)

But a printed case is welcome and easy: my idea is to use the same
shape as the GTA04 board so a spare Openmoko case would suffice.
And there had been 3D data around to print such cases.

>> Now, the idea is to provide a PCB very similar to this, but have:
>> * the correct spring loaded battery connector
>> * some metal handles (cut&bent a copper staple and solder to the board) to keep the battery in place
>> * an Mini-USB socket so that you can connect to a standard wall charger or a PC or hub
> This is good, as long as it brings enough power (surely for charging one battery
> it will, but for 2 or 3 ? )

800mA each. You just need a sufficiently powerful 5V supply for each battery.

>> * it should even be possible to strap together with the GTA04 Qi-Charger:)
> Good, I'm not interested in inductive charging, but why not ?
>> * a LiIon charger chip that can run a charging cycle w/o any CPU support
> And maybe take care of the charged battery if left there for longer
> than needed ?  Would it need to eventually recharge ? Maybe that's too
> complex and depends on user wishes so best left out ... ?

That is all inside the charger chip. It trickle charges if needed and turns
automatically off if battery is full. I am quite sure that Texas Instruments and
their customers have already thought of everything when designing these chips...
They are used in millions of digital cameras, gps devices, smartphones etc.
where user's don't care about the health of batteries.

>> * some LED(s) to show the charging status
>> * is likely ~20€ per unit
>> I think you can then just take two or three of those and connect to some
>> (old) externally powered hub to charge several batteries in parallel.
> That would be better than what I have now (nothing). But it would
> still require
>   2 o 3 of these units
>   1 power hub
>   1 hub power source 
>   3 or 4 cables 

If you already have it, it would be fine.

>   some case
> Doable at home, not so much to take to a hotel, I guess...

Ok, I see.

Maybe if you have a notebook with multiple USB sockets it would only
need to carry extra cables.

There are also USB power supply devices like this (I don't know if this
specific one is good): https://www.monoprice.com/product?p_id=13915

> It's ok but if something could be done to eliminate components it would be 
> even more convenient. Remember those AAA rechargeable battery chargers ?
> They have several slots (at least 2) and you don't need many of them. Some
> plug directly to a wall socket and you don't even need a plug. This is 
> asking too much, but maybe some reduction in components is still possible.

Well, there aren't many to be reduced. You always need a battery connector
for each slot and a charger chip for each battery (batteries may be differently
filled and become full at different times).

And you need a PCB space at least as large as each battery.

So the only thing you can share is the connector to some wall outlet and
the wall charger.
> Maybe an optional version with more battery places or maybe some male
> and female connector in opposite sides so you could daisy chain 2 or 3
> of those chargers side by side without needing cables and without a
> powered hub

That looks like an interesting idea!

> (but then it's no longer USB 2?).

Well, charging doesn't need to be 100% compliant. It can be seen as "just
another connector type" for a 5V 2A power supply.

Maybe it should be possible to limit charging current to 500mA each so
that you can chain up to 4 units with a 2A supply.

>> Would this fit your needs? Would others be interested as well? Additional ideas?
> It would, and I think I would get 2 or 3 of them if there isn't a more
> integrated option. But if possible I would pay more than this total
> price for a more integrated option.

Well, there is nothing to save in a more integrated version. Space
goes up linearily and number of components as well. The only wasted
space is that a GTA04 shaped board is a little bigger than it would
need to be.

So with the daisy-chaining idea (if it can be done) there is maximum
flexibility (i.e. you can start with one, extend to two and three).

>> Generally, this discussion has already turned out to be very fruitful!
>> We already have identified as not difficult to provide:
>> * Qi-charger kit for GTA04 (working prototype already presented a while ago: https://twitter.com/goldelico/status/815234456126689280 )
>> * FST-01 crypto-key clone (Big-USB or Mini-USB plug for GTA04)
>> * standalone GTA0x battery charger for HF08 batteries
>> More ideas are welcome! Make GTA0x great again :-P
>> BR,
>> Nikolaus


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