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I am working on an ATTiny programmer (because it is fun and existing ones did not quite meet my desired specifications, most notably USB-C connector). My first version used a standard DIP-8 socket to hold the ATTiny. This is fine, but it is a little bit of a hastle getting the chip in and, particularly, out.

I cannot find an 8 pin ZIF socket, and even if I could they are a little bulky.

It occurred to me that I could simply use appropriately sized plated holes or even just pads and set the ATTiny onto or into them, using gravity, friction, or a finger to hold it in place during programming.

I am happy to attempt it, but before I made educated guesses about the size of the holes, I wanted to reach out to see if others have done this before and had any advice or clever ideas about size and shape of the holes to maximize electrical continuity while minimizing insertion and removal force.

(If anyone is curious, a 3D model screenshot is attached and the project details are here: https://github.com/ejkreboot/attiny_stick. The current version does not work...I need to change my "reset" wiring. Thus creating the opportunity to rethink the DIP-8 socket!)

ATTiny programmer

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    \$\begingroup\$ Sounds like to are trying to guarantee yourself heartache by creating a bad intermittent connection between programmer and part, thinking about getting stiff holes to be the right size. Normally we have trouble with intermittent connections that are intended to be good. \$\endgroup\$ Commented 6 hours ago

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In my honest evaluation of your proposed idea it is nearly impractical. You should be strongly thinking about a 8-pin DIP Clip that you attach to your programmer board with short flexible cable (think silicone insulated wires).

DIP Clips can be found in many places but this picture from the AliExpress web site does a great job of showing how to simply insert your bare IC into the clip.

enter image description here

Picture Source: https://www.aliexpress.us/item/3256809349438841.html

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First off, the "easy" thing you might not have considered: a DIP-8 also fits in a DIP-10, -14, -16, ... zif socket.

The other thing: yes, what you describe can work, but badly without very controlled alignment and uniform prssure and aligning contacts by hand is terrible and prolly lot more work than using yoir DIP-8 socket with a good IC lifting "pincer" tool.

I'd instead go for 3D printing a recepticle with 8 conical holes into which the 8 legs of the DIP IC can "fall", with spring loaded contacts underneath to make reliable contact once a slight force from above is exerted. The springs mean you dont have to exert very uniform force.

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  • \$\begingroup\$ +1 A lot of 40-pin ZIF sockets will accommodate either 0.3" or 0.6" row spacing and may be cheaper/easier to source than smaller ones, however that doesn't deal with the bulky issue. \$\endgroup\$ Commented 12 hours ago
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Some ideas that come to mind:

  • Two rows of plated thru-holes on 0.1" pitch, spaced apart somewhat more or less than the standard 0.3" (possibly two rows straddling 0.3"?) to force the DIP pins against the walls. I'd be a bit concerned about wear.
  • Single-position receptacles for square pins, but sized for larger pins than the DIP actually has. Some testing may be necessary to find a size that gives consistent connection with minimal retention force.
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