So I think final version of programming key and port I will use in the future designed

board thickness 0.8mm, small enough to even be applied to 17mm drivers

2 possible layout of the driver port, any combination of pads and vias is possible but at least 2 viases should be used for alignment

electrical improvements so far
rearranged pins to fit MCU pins arrangement better than original v1.0 had

pitch is 1.3mm so with 0.8mm 6 mil traces can be routet between them, also added a variant with just 6 viases if this can be fitted on driver
basically only 2 connections need to be viases to align the pogo pins

improvement machanically on key
2 traces on the pogo pin board to self align it by the solder
increased pad size on driversfrom 0.6mm to 0.8mm, to compensate wrong aligned pogo pins
length of the solder traces on board reduced as some flux went in the pogo top, can be solved with alcohol but more distance is better
Added a key head for easier handling
added 2 holes to use a wire strap to secure the programming wire

on drivers
cleared solder mask around alignment pins as sometimes the solder mask covers the whole hole (not Oshpark but cheaper fabs in China)
0.8mm Oshpark board a bit more thick than anticipated, 0.1mm added on drivers port pad distance between the 2 layers

Picture of v1.1 key on V1.0 board, pin alignment does not work (no self centering while reflow) on the small 0.6mm pad
I moved the pins further below, because having solder paste next to the pin hole is no good idea
also the solder mask on the outer alignment viases is blocking the holes, so added solder mask around them

Those are 0.5mm thick pogo pins with a 1.3mm pitch, not the 1.02mm with 2.54mm pitch

I also got my final revision 3.2 also launched now on Oshpark

the v3.1 boards i have here can be used but with some advise
I got made 120 boards where the 10 pin header wont work when used with 1:1 wire, 4 traces need to be swapped out
and solder connection markings do not fit
- and R are swapped and Mosi and Sck

the pins are mirrored because I made an mistake looking in my program on drivers bottom which auto mirrors

Order in 2OZ for 0.8mm board thickness from Oshpark!

https://oshpark.com/shared_projects/o1pUPNqt

I got some that cant use the header as they were produced mirrored

Production

applying solder paste one side
soldering pins to it and applying thermal glue for 2. side reflow

Both sides soldered, fine alignment of the pind with soldering iron carefully after that picture

final key with soldered wires not connector

HarleyQuin wrote:

Nice concept. Any chance for a short description? I really like the idea of an on-the-fly programming stick, I just can’t follow from the pictures: For which mcu is it, why 9 pogo sticks, how far are the sticks apart (center to center), why are the sticks on a different height, how is the programmer connected to the key? Much appreciated.

It works as it is, plese comment only if you have further improvements or want to discuss details
If you want to get the footprint for your design program I can mail it to you (Gerber or Diptrace libary)

3 orientation pins are sticking out further and rest in viases
6 Pins are connected on the driver design to the MCU pins for programming, any MCU that can be flashed with USBASP programmer

ToyKeeper wrote:

Lexel wrote:

3 orientation pins

Why 3 orientation pins instead of 2?

Also, for making it even more compact, what about having only 6 pins total and making some or all of them vias? For people who don’t have a key, vias are a lot easier to use than pads.

It’d be awesome to get a standardized BLF programming layout and key, so I hope to maximize the amount of drivers it can fit on while minimizing the barrier to entry.

making all programming pins viases blocks a bunch of area on small drivers likely make routing very hard if its packed with componets, with pads you are way more flexible, as they block that area only on one side
It is possible to remove one centering via where now 2 are, you can design the driver with just 2 centering viases
also tolerances play a big hole making it 6 viases, 6 pads are far more tolerant if pogo pins not aligned perfectly

joechina wrote:

Does it make a difference, if the pin pitch is 50Thou or 1.3mm ?

For pogos on pads I think no.
But for pogos in vias it adds up:
5 pins = 5 distances
5*0.03mm = 0.15mm

So the outmost guiding pins are 0.15mm off IF the pcb manufacturer set the 1.3mm to 50mil.

Edit: just saw you have variable pin pitches

(could be a possible trap to fit the key int the vias and it’s also possible that I am overthinking)

Edit:
Die Maßangabe
0.85 and 0.91
What is it, a tolerance?

0.91 is the solder Mask I cleared around the viases, fabs often fill the viases with solder mask if you have no clearance around them
also the fab has to produce from your gerbers there is no converting pitch 1.3mm to 50mil
also the 1.3mm was choosen so you can route a 6mil trace between the pads and pads and viases, if its 1.27mm you can not route it with the nessesary clerarance withoput making the pad and viases smaller

here an example

Tom Tom wrote:

ToyKeeper wrote:

Lexel wrote:

3 orientation pins

Why 3 orientation pins instead of 2?

Also, for making it even more compact, what about having only 6 pins total and making some or all of them vias? For people who don’t have a key, vias are a lot easier to use than pads.

It’d be awesome to get a standardized BLF programming layout and key, so I hope to maximize the amount of drivers it can fit on while minimizing the barrier to entry.

Agreed, no orientation pins required. This is not a tool for the un-initiated, placing it the right way is hardly rocket science.

The point of this is to facilitate ISP with the latest MCUs where external clips are not an option (no leads). Which was always a rickety arrangement, involving USBasps, headers, cables, clips etc.

Best if all pads are also vias, so self-locate.

Six pads/vias. No more. No extra “orientation” stuff, just obvious silk screen.

Frankly, this was all sorted out long ago, it’s not new, e.g. just google “pogo pin isp programming adapter” and follow the (unofficial) standard.

Then do it.

OK so pogo pins with a bit larger head, pitch 1.3mm
but the inofficial standard bases on 2.54mm pitch, then we make it larger again

Problem with this is often below the MCU is something that blocks it like spring pad or so
here a driver example

Tom Tom wrote:

Lexel wrote:

Tom Tom wrote:

ToyKeeper wrote:

Lexel wrote:

3 orientation pins

Why 3 orientation pins instead of 2?

Also, for making it even more compact, what about having only 6 pins total and making some or all of them vias? For people who don’t have a key, vias are a lot easier to use than pads.

It’d be awesome to get a standardized BLF programming layout and key, so I hope to maximize the amount of drivers it can fit on while minimizing the barrier to entry.

Agreed, no orientation pins required. This is not a tool for the un-initiated, placing it the right way is hardly rocket science.

The point of this is to facilitate ISP with the latest MCUs where external clips are not an option (no leads). Which was always a rickety arrangement, involving USBasps, headers, cables, clips etc.

Best if all pads are also vias, so self-locate.

Six pads/vias. No more. No extra “orientation” stuff, just obvious silk screen.

Frankly, this was all sorted out long ago, it’s not new, e.g. just google “pogo pin isp programming adapter” and follow the (unofficial) standard.

Then do it.

OK so pogo pins with a bit larger head
but the inofficial standard bases on 2.54mm pitch, then we make it larger again

OK, I agree 0.1 inch spacing is quite large by modern standards.

But what is available at smaller pitch ? The smaller you go, the more esoteric the components become, and the method of assembling them. An FR-4 key is as basic as it comes, maybe a bunch of pins glued together with e.g. Sugru even worse. When I started this idea I suggested a 3D printed matrix to assemble things, I still think that’s the way to go for something reliable. But lets see where this goes.

Bottom line is that a standardised ISP connection on the accessible face of the driver is very desirable. If it can be connected with a click or a twist, even better. But a simple pressure contact with half a dozen pins on a standard pattern would be fine, even if only a couple are vias, for location.

this is why someone wrote me to use 2 traces so the pins self center themselfes while reflowing
with this method no worrying about it, just put solder paste and pins on the board and reflow it, perfectly aligned

on most of my smaller driver designs going with a 6 viases programming footprint wont work, because its literally packed by tons of traces on top, and also the spring pad and other stuff will limit it a lot where you can place the programming port

Problem with this is often below the MCU is something that blocks it like spring pad or so
here a driver example with 24mm size, not as small as a 17mm for example, I had no idea if its even possible to get the 6 viases on my 17mm or not

I thought about it why not make a 7 pin pattern which works for pads and viases, and modified it a bit

OP updated with some modifications taking feedback into account

removed 1 orientation pin
and moved GND pad to one orientation via

pitch is 1.3mm I stick with it to get 6mil traces between the pads

Both options now possible
2 viases for alignment and 5 pads
or 6 viases

ToyKeeper wrote:

This is looking pretty good.

It might be possible to make the connector even smaller though, by moving that ground via into the old ground pad’s location. Or maybe it could be useful to re-add the ground pad, so the driver layout can use either the via or the pad (or both) depending on what fits easiest. Sometimes a really small board could end up using only one orientation pin, but that’s not necessarily a problem. Small boards would even have the option of omitting both guide vias if space or layout restraints are tight.

I found aligning it on 0.8mm pads with only one via would be hard, but yes generally you could say make at least 2 of the pads as viases so the key aligns to the other pads
I think some people are underestimating how small this thing is with only 1.3mm pitch

likely best would wotk get 2 of the outer connections as viases, which ones they are is less important, but I designed 2 pogo pins to be sticking out further on the key (- and 2. centering via)
the further their disteance is the less gets twisting an issue just notice if used only 6 connection pins the max distance is 2.6mm

also thinking about a key with a header for USBasp

Tom Tom wrote:

It still looks clunky to me.

I say again, no need for extra alignment pins, just the six required for functionality. Make two of the pads (preferably spaced as far apart as possible) also vias, and it will self-align under pressure, all pins the same length.

Your key is far too wide at the bottom, no reason for this.

Yes it should have a header to accept the standard USBasp.

Take a look at e.g. https://www.tindie.com/products/madworm/tiny-avr-isp-pogo-pin-programmin...

and

https://cdn.tindiemedia.com/images/resize/TsJPGkLTag5mPY9qTmjbcMmfous=/p...

to see how a half size (1.27mm spacing) 1/4 the area thing looks. And buy one for $6.50

By the way, this is very very small, not something for the inexperienced to meddle with, or try to assemble without good skills.

As I’ve said before, this seems to be re-inventing the wheel, it’s all been done before, but maybe there is a better wheel to be made ?

Frankly for our purposes only four pins are needed, Vcc and Gnd can be supplied otherwise, e.g. with croc. clips.

clunky?
if we use the standard idiot proof USBASP header with 10 pin and the plastic casing there is no means how small the front of the adapter is
really noone wants to make a 10 to 6 adapter cable just to make the programming key 8mm thinner
lower end is 12mm and upper end 22mm right now, this is a lot smaller than my house door security key, no need to make it smaller than this

to give you an idea how small we already are look at the v1.1 size compared to my house key

as you self said the micro Key you can buy is too small for really safe flashing if you dont want to check if it sits right with maginification glass
there is really no need to make it smaller than an average Attiny MCU is just because it is possible with 0.33mm pogo pins heads on 0.5mm tube going to 0.7mm pin distance

Tom Tom wrote:

see how a half size (1.27mm spacing)

we are not going to challenge how small it can be done, who cares if the pin distance is 1.27 or 1,3mm in real life on just 2×3 pin you wont see any difference with pogo pins anyways,
if you really want to buy the “standard 1.27mm” key you can fit it on my programming port with no problems

the additional Pogo pins are totally optional making placement and aligning of the key easier for people who can not solder 0402 or 0603 anymore because of age (Eyes or hands not allowing it anymore)

but you got to have some error margin in placing it on a driver
you ever destroyed a MCU because the SOIC clip or in this case a pogo pin key went off during flashing? No I dont want it as small as possible exactly to avoid this

and on complicated driver designs you are really happy if you can route a trace between things

so if you want to pay 10$ with shipping for a 1$ parts and 2$ labor costs adapter go for it noone is going to stop you bringing your drivers with this port on market