[Tinkerphones] New tinkerphone gadgets in Goldelico shop?

Xavi Drudis Ferran xdrudis at tinet.cat
Mon Nov 13 12:56:54 CET 2017

El Mon, Nov 13, 2017 at 11:36:16AM +0100, H. Nikolaus Schaller deia:
> 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.

Well, I don't care about the PCB shape. This is as good for me as any other. 
A new case should be easier if the PCB was rectangular, just measure where the
connectors go, I guess? 

The only advantage I can think of for having the same PCB shape as
GTA04 is that with some case or something acting as spacers you could
maybe stack 2 or 3 chargers with their batteries and the phone on top,
and save desk space w.r.t. horizontally placed chargers (which was my
first thought). Not terribly worth spending any time on, possibly. But
vertically stacking chargers would make inserting and removing
batteries phisically more difficult, wouldn't it? It is desirable not
to have to unchain the chargers to replace batteries in them. But if
the vertical space between chargers is large enough to comfortably
insert and remove batteries, the daisy chain connectors won't touch
without some extra complication ?

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

That would be doable. For me it would be better to have a single 5V, 2A  or 3A
for 2 or 3 batteries, or whatever, than needing 2 or 3 supplies or a power hub. 
If a non USB connector helps reducing the wall sockets , cables or suppliers
needed, then that'd be a good option. 

> 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.

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

I don't know about others, but I tend to have the USB sockets I need 
(or sometimes less). So I still would need some dedicated hub for charging, 
most likely. 
> 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

Yes maybe stock some of these or similar to simplify buying with the charger. 
It'd still be simpler for me the more integrated it could be, but it's 
not really necessary, just convenient. 
> > 
> > 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).

I may have misused the term. I didn't mean electronic components, just
"solution components".  Meaning gadgets on my desk or in my suitcase.
Individual pieces taking space and (a very little) complexity when using it.
Even if it is a tinkerphone, I don't think people love to tinker when 
doing vegetative stuff like charging. You just want something that doesn't 
give you a badly connected cable 20% of the time, or complicates 
cleaning the dust or ... But maybe it's just me. 
> So the only thing you can share is the connector to some wall outlet and
> the wall charger.

just this only sharing would be attractive. 
> > 
> > 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!

Side to side ? or stacked one in top of another ? 
can you daisy chain the phone too (easier if the connector is USB) ? 
> > (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.

Ah, ok, I thought there might be some advantage to USB compliancee
about possible compatibility with cables or connectors or something.

But you could also daisy chain with barrel connectors if that helps at
all (in case the total power wasn't feasible for USB and took a
dedicated supply or something). USB seems preferable if possible.

> 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.

Well, for me charging slowly is usually no problem if I can leave all
batteries I need to charge overnight. 4 batteries would be plenty, 3 
usually enough.

If the same charger can operate at 500mA when daisy chained and at top
speed when you need to charge just one battery quick (or you provide
each charger with a supply instead of daisy chaining) maybe everybody
could be happy ?

> 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.

Again me misusing language ? I mean I prefer to have one device with
one plug and 3 battery slots than 3 devices with 3 cables and 3
supplies because even if I waste some electronic components when I
just want to charge one battery, I save in use complexity (and total
space, because cables and supplies take space and maybe wall sockets,
scarce in most hotels). By more integrated I meant less gadgets to set
up, not like VLSI or BOM optimization. But daisychaining with just one
supply, one cable to first charger, n chargers plugged together, and
(optionally) a cable to the phone would be "integrated enough" for me.

About space wasted. It doesn't look like a GTA04 PCB shape wastes a
lot of space. If that is more convenient for you go ahead (does it
save design time?). If you want to make it smaller, just do so. I'd
imagine a rectangular shape would minimize material waste (PCB
substrate). Not a big deal, I guess. You can make a PCB for a single
battery as a smaller rectangle than GTA04 and save as much space as in
a bigger PCB for several batteries (just saves daisy chain connectors
in the BOM, but maybe appeals to fewer people).

> 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).

Yes if daisy chaining is at all possible it sounds as the perfect 
solution. Just document the maximum safe length of the chain and 

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