PiicoDev Precision Temperature Sensor TMP117 (CE07502)

Hey @Pete56180,

PiicoDev gear should work fine via the QW/ST connector along with the PiicoDev TMP117 code examples for RPi Pico

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Would also like to know if your Piicodev RTC module will work with it.

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Hi Pete,

All the PiicoDev modules use the same JST SH / Qwiic / STEMMA QT connector (that connector has a different name for every manufacturer that uses it). So you should be able to add the PiicoDev RTC to the daisy chain just fine, you’ll just need to check that nothing is using the same I2C address and change the from the default address if you do wind up with two modules using the same address.

Hi, I have version 1.2 of the board with the DIP switch for address selection. I am going to be permanently mounting this to another board with 10mm standoff to enable good airflow. The holes for the pins though are not in the same alignment as the “standard” on PiicoDev Mounting Guide - Tutorial Australia. Can I please get confirmation that the holes for the pins are the same distance from the mounting holes as per the standard and that instead of straddling the centre line, the SCL pin is on the centre line? I just want to make sure it is perfectly aligned on my board. Thanks.

Hi Doug
I bought this up last Nov 22 in this thread

New video by Michael; The Factory | Design A Product With Us Part 3: PCB Design In KiCAD

The short answer is no, I don’t think they will line up. Unfortunately this seems to be a universal problem and can be quite a nuisance. I think someone must have has some sleepless nights thinking up a way to make things as awkward as possible. I think there may be one or two manufacturers that align any pins AND the mounting holes on a standard 2.54 (0.1") PCB grid but it is very rare.
Cheers Bob
The solution I have found is to mount the small board then connect the pin positions with a slightly smaller tinned copper wire so they can be bent half a hole to mate with your larger board holes. A nuisance but it is a neater solution than butchering boards to get the mounts to line up.

Thanks Robert, however I was hoping that they would stick to their standard as they discuss the mounting holes and provide information on the pin spacing in the link I shared. @Michael may have some information… I do not use KiCad, so I can’t just load it up and see.

Hi Doug
I don’t think there is a standard". True the header pin holes conform to the 2.54mm grid and the mounting holes conform to a 2.54mm grid BUT NOT THE SAME GRID. They seem to be half a hole out in both directions.
Bewildering what???
Cheers Bob

Hi Robert, Core Electronics have their Piicodev products and have documented the size and position of the mounting holes and the pins in the link I posted. That is why I’m asking - I’m not worried about other boards, I’m asking about a Piicodev board designed by Core (hopefully) to their layout standards.

Hi Doug
I have already had this discussion with Michael as in that link above.
I am sitting here looking at 2 boards. One PicoDev and one Adafruit. Neither have the header pin holes and the mounting holes on the same grid.
I would respectively suggest you purchase the board you are interested in and try it. You will find I think that I am correct.
Cheers and good luck. Bob
Just had a look at that link. All the dimensions are there. It stands out like a neon light that the mounting holes and header pins are not on the same 2.54mm grid. For instance one dimension shows the header holes 1.27mm from the edge of the board and the mounting holes 22.4mm from the same edge. Now subtracting 1.27mm from 22.4mm leaves 21.13mm. This is not evenly divisible by 2.54 so cannot be on the same grid. I don’t think they are even on the same 1.27mm grid. This is all good if your connections are cables but is a bit iffy when you are trying to use header pins and mounting stand offs as you want to do.

Hi Robert, I have three of the Piicodev TMP117 boards and I don’t really care what grid they’re on as I can put holes anywhere I want on my board. I just need confirmation that the TMP117 board has the pins the same distance from the mounting holes as specified in their standard for Piicodev boards with the referenced pin on the centre line. It would be nice to have everything on a 0.1” grid, however it isn’t always that easy when designing boards. Core have chosen their layout, and that’s fine with me. I just need the clarification I mention. If I used KiCad, I could just load up the board and check, but I don’t use it and I’m not sure I trust conversion programs to get it right.

Hey @DougM - I can confirm the vertical distance is the same and the SCL pin is centred.
Uploading: image.png…

The rev20 board introduced the 4-pin DIP switch to make addressing easier / solderless.

The Mounting Guide is slated for a major update. In the meantime I’ll update this line:

1-unit modules all have similar outer dimensions, mounting hole, and PiicoDev connector placement. The number of pins in the breakout header differs module-to-module, but is always centred.

To read something to the effect of:

1-unit modules all have similar outer dimensions, mounting hole, and PiicoDev connector placement. The number of pins in the breakout header differs module-to-module. The breakout is usually centred. Download the PCB source files to check a specific board.

@Robert93820 hindsight, eh? :woman_shrugging: It turns out most of the long-term decisions in a project get made (or not made) right at the beginning - when you have the least benefit of hindsight and experience.

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Hi Doug.
Sorry I misunderstood. You have cleared that up. I thought you wanted to open up an existing hole on a pre-drilled proto board or similar. That was the reason for my original query to Michael. “Why can’t these holes be on the same grid” as a good percentage of experimenters and “makers” would use this type of board (myself included). Your query to Michael is well founded but I believe Core make (or try to) these boards the same dimensions to “standardise” on this form.

I see Michael has replied before I got to post this which has answered your original question.
Cheers Bob

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Hi Michael
Sorry if I seem to have made a big deal out of this. While it can be a nuisance it is not hard to overcome. It is only that the mounting holes and header pins are not on the same grid. The spacing is however on a 2.54mm grid so if I need to use the mounting holes I use tinned copper wire bent to accommodate the slight offset instead of header pins as described above.

Hindsight is wonderful but I don’t think you have the luxury of a full on model shop and lots of heads to iron out some of these little details before full production.
But FULL MARKS for having the foresight to design and manufacture locally. It is a pity we don’t see more of it.
Cheers and keep up the good work. Bob

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Thanks @Michael, really appreciate the confirmation. I will design my board now very happy in the knowledge that it will fit. I am always loathe to trust the calipers! Appreciate your help and thanks for designing, building and supporting your kit all in Australia! Cheers, Doug