Prototyping board with 20-pin mezzanine plug/s

[Stevo52]

I am new in here, so forgive me if this has been raised previously.

Armed with a PYB-D, WBUS-DIP68 and a few other bits and pieces, I am enjoying the PYB D series 'system'.. so far it seems well thought out and geared towards more complex product development. I have successfully ported a couple of previous projects to the Pyb D, which is more accurate, more stable and less prone to obscure issues than the platform I used previously. It has meant adopting some other 3rd party devices, but that has gone quite easily so far. Now I want to add some other functionality and the WBUS-DIP68 looks like a very good way to accommodate this, rather than have two separate devices tied together.

Do my question is, is there a 'Prototyping' board to fit the 'mezzanine' sockets on the WBUS-DIP68 / WBUS-DIP28 in the development road-map, or already available from somewhere? I would like to develop some custom sensors that would plug into these sockets eventually. At present I am working on the sensors using the WBUS-DIPXX boards into a breadboard, but that becomes quite a briar patch . So I can see that adding multiple sensors (i.e. multipe gas sensors) via extending the signals on the mezzanine ports would be useful with a separate, isolated, power supply for the high current component such as element heating, of some of the sensors.

if there is nothing like this planned, or available then I might have to design one up. Any help/comment would be appreciated..

[jimmo]

Hi,

That does sound like a useful board to have. Just to confirm that what you're looking for is like this sort of thing https://learn.sparkfun.com/tutorials/sp ... okup-guide (i.e. 0.1" PCB holes in a breadboard row configuration, with a WBUS connector, and maybe one or two tile spots?).

This is something I am looking at building (amongst other adaptors and tiles). I'll update in a few days.

I'm kind of imagining a wider WBUS28 or 68, with 5 rows of holes on each side instead of one. Plus some additional prototyping space and +/- rails down the side.

Jim

[Stevo52]

Hi Jimmo,

Pretty much what I envisage for a prototyping board. My ideal would be:
i) a small unit with the prototyping area just to one side,
ii) a wider unit, prototyping area on both sides,
iii) possibly allow for piggy backing another tile on top.. as per the eMMC module?

Main thing would be to allow it to still plug in to the WBUS68 alongside other tiles or to only take up a normal one or two tile space. Does that make sense? Power rails would be a good idea if space permits.. plus pads with approx 4 holes, to connect external supplies.

Is there a 'roadmap' of proposed future additions to the Pyboard D range?

[pythoncoder]

There are probably as many sets of requirements as there are users but here's what I'd like to see. A Wbus-dip32 which brings out the pins exposed on the Pyboard D edges to a 0.1" pitch with a 0.6" row spacing akin to the Wbus-dip28. This to be sold with pin headers so that it can plug into a standard breadboard.

For boring reasons to do with old age I can no longer solder anything more challenging than 0.1" pitch pads, preferably with a solder mask. I design my own PCB's for permanent projects: with these the only way I can use Pyboard D is via 0.1" adaptors. But many beginners lack soldering skills: the Pyboard D series is closed to them if they want to use anything beyond the standard tiles.

Regarding pins, I've already hit limitations with the Wbus-dip28. The Wbus-dip64 is great, but it's rather large in terms of length and row spacing, the latter limiting its usefulness on standard breadboards and making my PCB's needlessly large. 32 pins would bring out both I2C and SPI buses along with the CAN bus.

[jimmo]

A Wbus-dip32 which brings out the pins exposed on the Pyboard D edges to a 0.1" pitch with a 0.6" row spacing akin to the Wbus-dip28

Yup, agreed! I would use this too.

Just to confirm that we're on the same page:
32 = X*12 + Y*12 + 8 (gnd x2, Vin, Vbat, boot0, vusb, 3.3, reset)

Would you match the ordering of the outside edge of the pybd exactly (i.e. interleave X and Y). ?

[pythoncoder]

Yes, same pins but different ordering. I'd keep X and Y together and in order to avoid splitting pins which are logically associated such as CAN, I2C and SPI. This makes it much easier to produce a drawing showing usage: compare and contrast the excellent Wbus-dip28 drawing with that for Wbus-dip68 which omits those interfaces because their pins are scattered to the four winds.

[Stevo52]

That would be a useful board as well I think. It would be good for breadboard experiments/development.

I would still like to see something like a tile proto board though, to build one or more sensors directly onto. I am also suffering from the dreaded age related vision loss (especially fine detail) lurgi, but something on the 0.1" pitch would be useful, manageable and allow for use of commonly available components.

[Roberthh]

Looking at the board I do not understand the need for the 0.05" spacing of the pins. Give the total width including the little wings, there is sufficient space for a two row 0.1" grid connection. That may collide with the edge connector cutouts, but since the bottom side is not flat, it is anyhow inconvenient to use.

[pythoncoder]

My guess is that Damien may sell an industrial version lacking the SD card and wbus connectors which mounts flat on a PCB.

[Stevo52]

Hi, I am back on the development workbench after an lengthy absence for health reasons. Now that I am coding again I am enjoying it and slowly the ideas and competency is returning. it is good exercise for a 'lazy' brain !

Was there any further progress on developing WBUS prototyping boards as discussed previously in this thread??

Before I was rudely interrupted, I acquired some WBUS connectors, got some PCB's made and I have now built up some 'prototype' prototyping boards:

1. A single tile sized board that brings out all 20 WBUS connections, has a 0.1" spacing prototyping section, on board RGB Led and i2c interface (including pull up/down resistor space). You'll all know the vagaries of i2c buses I'm sure - inconsistent?

2. A DIP28 sized board with:
i. a WBUS connector to fit to the DIP28 (parallel to the DIP28
ii. 3 WBUS sockets for tiles
iii. WBUS connections on 0.1 SIL connector (allows further expansion and is perpendicular to the DIP28)
iv. LED/i2c plus an Address jumper block
v. a control relay (to switch external power in most cases) - this may be replayed with an opto-isolated solid state switch arrangement.

3. A DIP28 sized board with WBUS on 0.1 SIL connector and a larger 0.1 grid prototyping are (1, 3 and 4 hole strips)

The idea was to replicate the DIP68 functionality (multiple WBUS connections) but allow the use of the DIP28 for power options & management (which is lacking on the DIP68) and allow further WBUS expansion depending on what sensors are being developed. For example, some gas sensors require a heating element with power requirements well above what the PYBD can provide, higher voltages too. In the end, the final results of any end device, will use a 'Lego block' expansion concept. the long DIP68 board is OK but is an awkward size to encompass in a product design, especially where size is a critical factor - a block seems easier than a strip format for most of the development I undertake, especially as some sensors are quite large.

These prototyping boards satisfy my needs right now, but will need scaling down and resizing to pretty them up, but the prototyping space is great (soldered or pin/socket as required - which is what I prefer during development but once ready for construction, build the same thing hard soldered.

Have any other such devices been built? or developed to a ready for sale state? For me, he hardest part in getting the PCB's up and running, was the WBUS connectors fixing and placement but the PYBD product line was fairly new when I started.