LiPo SHIM questions


#1

Hello!
When using this amazing widget to power a Pi device does it take over the GPIO normally assigned to ttyAMA0? In this case the one for TXD. I ask of course because the one I bought from Micro Center here in the US a number of years previously was configured with the connector attached so I’d be able to use it with a variety of Raspberry Pi devices and not be tied down to the one it was soldered to.

I also use the serial port at ttyAMA0 as my first place to see that the device is connecting to a known working WiFi access point.

Now my next steps are to attach a stackable header to a Pi Zero with the connector used for the hats and exenders pointing down. That connector would sit in the thing used normally to attach to ribbon cables, and have the same style male header pins sticking up.

However all of this is a moot point as applies to the LiPo SHIM device and the working serial port on the Pi Zero.

On a side note I can tell all of you that the little guy is working splendidly with the different Pi Zeros I’ve tried it with an assortment of LiPo batteries. Not the typical 18350 types, the tradition flatpack ones. However would it work with that size battery?
I remain a curious fellow in the US.


#2

Pin out is here, https://pinout.xyz/pinout/zero_lipo#
It looks like it only uses GPIO 4.

EDIT: Not sure why the product page for the LIPO Shim, pinout link, takes you to the Zero LIPO Pinout?


#3

to respond to alphanumeric, the pinout.xyz says zero_lipo because that was the previous name.

From


says:
" LiPo SHIM (formerly known as Zero LiPo) "

And to respond to DrWho8, as alphanumerics says, there’s no conflict with ttyAMA0. but the lipo shim connector does cover those pins. if you access from the bottom that would work fine.


#4

Hello!
Are you sure about that? I am returning to this issue because I now have a project to support the one I picked up from Micro Center several months earlier. According to my 14 Element contributed thingie of the Raspberry Pi GPIO Header sheet for the A+, B+, the Zero and even the Pi2, but not the Pi3 it does not.
It makes it difficult to attach the Dupont connectors I am using to connect the jumper wires to the device however, and it requires that they be turned sideways to facilitate attaching them.

My only concern was in using the 18650 batteries I also have here to power the thing, since I have an equal number of them as applied to the regular ones which resemble the batteries I first saw used in a Palm Vx device, which I was replacing them.

That was asked because both the firm here, and Adafruit and even Sparkfun, plus Tinkersphere (also a store in NYC) sell the the big grunt, a pair of 18650s wired in Parallel format and the last photo is of the big one being used.

However, and this is one for the company, how come GPIO4 is being used? That’s a favorite of the kernel for One-Wire via GPIO settings. I can change it to GPIO17 by editting the overlay according as it happens.

I bring this up because that’s the project.


#5

Pin 4 was likely picked because its in that first group of pins and not used by i2c or UART. Using another Pin means making the header on the Lipo Shim bigger / longer.

As to your other questions, I’m having trouble understanding exactly what your asking?


#6

Well you did confirm why Pin 4 was chosen. Now after studying the device at work, and and during my first use of it I did try out that code blob from the Github for enabling low voltage shutdown functions, I can see why it was chosen.

What I am wondering if a single 18650 sized battery would work, instead of that one which shows a package containing two wired in parallel. That seems overkill to me.

And what I am describing is my latest Raspberry Pi project, that of a simple One-Wire sensor using the DS1820 style temp sensor and the resistor based pullup to 3.3V and the one-wire I/O data line would have been connected to Pin 4, (GPIO numbering.)

I believe the module can be instructed to select any of the other ones named as GPIO_GENx where the lowercase x is the number for the collection of these general purpose GPIO lines.


#7

What you need for batteries depends on how many ma is being drawn by your Pi and attachments, and how long you want to run on battery. On one of my projects I’m using a 6600 MAH battery, its 3 2200 MAH batteries in parallel. I wanted a long run time. Most of my other portable projects are running just the one 2200 MAH LIPO battery. Parallel wired multi cell batteries can in most cases supply more instantaneous current, than the equivalent single cell battery.
I have never used one wire and am not up to speed on how it works etc. I’d have to go research it to figure out all the ins and outs