Milled test point pins?

There was a nice exchange on social media about connecting to test points. (Photo stolen from that thread).

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It seems 1.2mm is a pretty standard test point size. Anything smaller seems to cost a bit more (more expensive/breakable pogos, delicate test rigging). I made this pin 1mm in diameter because smaller just seems a bit insubstantial.

The bread board pins are nickel plated copper. The other option is gold, which is more solderable but $$$$. I’m wondering if we can get then raw and dip them in lead free solder or something.

It’ll undergo some changes after I talk to the pogo pin boss on Monday, and I’m open to any suggestions.

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I snipped off the long side of the probe cables custom milled pin and filed the surface. Soldered it onto one of the test points on a pico. It didn’t solder as well as a copper or gold plated pin but after a few tries it stayed. Looks pretty cute to me.
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These arrived! Gold and tin plating. They cost close to $1 a pin :sweat_smile: We’re going to send some off to the twitter user who inspired them for testing.

Is anyone else interested in something like this? It might be a little too out there :slight_smile:

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Here are some more photos of the new pins. They are super cute! They stand really well once placed on a solder pad but they are also quite tiny, so you’d have to use tweezers to place them gently on test points.
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I like these A LOT! I was skeptical, but it really is nice. I’m hesitant to make a bunch though. They’re pretty pricey. We did a sample batch of 100 - 80 tin plated, 20 gold plated. The milling was around $60 (400 RMB), the gold plating for 20 tiny pins was 200RMB ($30).

We sent some to the twitter user who ask for a way to connect to test points. I’m eager to hear what he thinks. We have some extra so I guess I’ll put them in the shop, but there’s only ~70 left (10 gold, 60 tin).

We were warned about the tin plating turning sour over time. I lean towards gold, but the batches would need to be pretty large to make the cost reasonable. I get the feeling this is just a me and one other guy project, and that’s fine :slight_smile:

We also found something similar from a pogo pin maker, but not exactly built for this purpose.

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What I’m wondering is if the connection to a test point on a PCB is stable enough with these test point pins.

You most probably don’t want to have to hold the pins in your hand because you want your hands on your keyboard to be able to debug and work with your DUT. In my experience you need some mechanical force between PCB and test point to get a reliable connection.

The solutions to this I’m aware of use some weights and gravity or spring force:
Sensepeek PCBite
Pogopin holder 8.65€ 36% OFF|Componenten Ic Chip Module Printplaat Pcb Houder Elektronische Productie Lassen Vaste Test Sonde Circuithouder Klem A| | - AliExpress
Needle positioner 57.53€ 54% OFF|Data Reparatie Tool Sd Card Reparatie Geheugenkaart Reparatie Test Flight Line Tool Pc3000 Fe Tool Pc3000 Data Recovery Testtool| | - AliExpress

I think the ideas behind these are promising, but I consider the prices of all these quite hefty.

Maybe these ideas can inspire you and your good connections into the Chinese manufacturing network allow to create something with a similar usability, but at better pricing.

Here is the link to the PCBite as the forum didn’t allow me to add 3 links to a post:
Sensepeek PCBite https://sensepeek.com/

When looking at this tool:
Needle positioner 57.53€ 54% OFF|Data Reparatie Tool Sd Card Reparatie Geheugenkaart Reparatie Test Flight Line Tool Pc3000 Fe Tool Pc3000 Data Recovery Testtool| | - AliExpress

Acupuncture needles are available for very cheap and bending the front part with pliers is easy. The PCB base is simple. The only thing that would have to be custom build would be the needle holders.

Maybe using a magnetic but insulated base and holders with magnets on the bottom would make this more easy to use.

Here’s a low-cost DIY alternative → PIZZAbite

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Oh wow, the pizzabite is a nice piece of work.

A friend has a magnetic gooseneck thing in their office.One of the mid-range ones, I guess. It’s really cool, and it seems to always be in use when I drop by.

This is probably a better line of pursuit than a solderable milled pin, but I enjoyed getting to use the milled pin folks for a second project.

If anybody wants these pins they are available now on DirtyPCBs:

http://dirtypcbs.com/store/designer/details/ian/6651/soderable-smt-test-point-pins

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The pizzabite looks like a good idea.

But it still requires the holder set to be bought from Aliexpress and I’m guessing that this set is still a bit overpriced. So I went searching on Aliexpress for the main obstacle, the holder arms. I found these:

I ordered one each and will check if they are suitable.

I did some digging on taobao and 1688 a while ago. There’s a huge range of quality and options, bit most of it is not at all cheap even on the Chinese market.

My video testing Soderable SMT Test Point Pins

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I’m glad those finally got some love, thank you for sharing :slight_smile: It was a fun thing to make, but I guess Pizzabites/etc are the more “correct” way to do this.

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It depends. In my case, I move around a lot, and being able to carry the PCB with soldered test points is more convenient than bringing a PCBITE, haha.

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That makes sense. The goose neck things are a bit fidgety even when they’re not moved.

When I made these my thought was a simple, secure test point that I could solder on, and then pull off when I’m done debugging (or whatever). Or potentially permanent debug access to a console interface on a router/UPS/etc.

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@ian , Would you be willing to share the contact information for the milled pin folks? I have a design need for a similarly sized milled pin to provide a contact pad for a project I am working on.

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Hey @jgartrel - thanks for checking out the pins, and congratulations on your milling project!

I’m sorry, we don’t share our suppliers if they don’t already have an international presence. If the pin miller had a website, email address and had previously taken international orders I’d happily share, but it’s a really small operation.

If you want to find a contact directly I’d suggest looking for a factory with a presence on alibaba, though our experience is that they’re mostly resellers/agents. This isn’t intended as an up sell, but you could also contract Ru via DirtyPCBs, we can get a quote and we have the infrastructure in place to work with small factories and suppliers.

You may have so me experience with this already, but just for anyone following along let me outline the basic roadblocks for a small factory to do international business from China.

  1. Most small factories don’t have email and don’t have any English speakers on staff. They may be able to rope in a son/daughter/cousin who speaks a bit of English, but it’s going to be really hard on you and the factory to address any issues with the engineering team. The lack of email means you’ll need WeChat, which I think is doable these days.
  2. While mid sized companies generally have (the boss has, a relative/friend has) a Hong Kong company/bank account to receive foreign funds, smaller companies expect cash RMB payment.
  3. Receiving wires in a foreign currency and exchanging to RMB is not easy. The company needs to be a certain type, with a minimum capitalization and various import/export licenses. Once they have all these licenses the VAT rate they pay on all their purchases increases from 3% to 17% (at least when I was actively running a Chinese company). The factory can’t access the funds until they have a valid export declaration showing the goods left the country at a customs value matching the amount of the foreign wire. There is an opportunity to refund that 17% VAT, but only if you can produce an official fapiao (government tax stamp) chain showing that everyone in the supply chain also paid 17% VAT. To do all this someone, probably the CEO, will have to spend half a day sitting in the bank (ask me how I know :wink: ) while the poor banker spends hours on the phone with the head bank trying to figure out how to do all this because it happens so infrequently (big export companies have bankers specializing in this, small companies don’t). That’s why you almost exclusively see massive foreign facing agglomerations like SZLCSC (JLC), Aliexpress, Alibaba, which act as an umbrella for a consortium of small and medium size manufacturers pooling resources to address the export and foreign currency handling issues.
  4. Small factories don’t have international logistics contracts in place. If I want to ship internationally from the Netherlands I can make an order online and DHL will pop around to pick it up. In China you can do the same for domestic shipments, but for international shipments they need a proper contract in place. It is rather involved and requires a lot of company stamps. Instead small factories usually try to find an agent to handle the shipping and end up passing on grossly inflated freight costs to you (see Aliexpress/Alibaba non-Ali shipping options prices for example, $200 to ship a sample via DHL). The one exception to this used to be “Sussie Shipper” in HuaQuiangBei, a street of rouge shipping agents that gave decent rates, but I think those days are long gone and a small factory isn’t going to drive your order to HQB for a back alley shipment drop. Additionally, even if you can find a way around the currency control issues in #3, the logistic company (DHL, UPS, Fedex, etc) will require the export declaration even if the government doesn’t mandate it.

In summary, the difficulties are:

  • They usually can’t be contacted by email
  • Nobody speaks English
  • It is very difficult to receive payment, with very real long term impacts if done properly
  • They don’t have a way to ship internationally

Now there are ways around this, official and unofficial.

  • It’s (was) common to ask for payment to a personal account in China (against a $50,000 per year personal exchange allowance). I don’t want to drag this out further, but there is scathing blog post (at least one…) about an agent that ran their company this way. Just don’t do this, it may even create problems for you with your local bank (verify a family relationship to this recipient).
  • When China wants to increase exports new cross border payment methods pop up. At the moment it is fairly easy for registered factories (business license type, minimum capital injection) to open a cross border payment account at a bank in Hong Kong. There is still paperwork involved for each transaction to satisfy the currency control requirements. When China swings to be less export friendly these methods disappear.
  • Some of the new western payment platforms like Transferwise now do USD/RMB remittance into China. It may be cheaper and easier for you than a bank wire, but the recipient will still have to deal with #3 on their side at least once.
  • You can go to China, pull money out of an ATM, and pay in cash. I highly recommend this method. It’s reliable, you develop a face to face relationship with your supplier, and it is to the best of my knowledge legally sound (up to a certain limit). Even with a language barrier everything goes so much better in person. You still need to arrange shipment, so that’s a couple days wandering round HQB locating the current shippers alley, which is honestly one of my favorite things to do :slight_smile:

Your best bets are a platform like Alibaba, or going to China in person. The issue with Alibaba is you run into agents who have no idea what they’re doing but they do speak English. If you do manage to get a real factory, then they’re probably too big to do the vaunted low volume runs that makes Shenzhen such an attractive place to manufacture. That’s the huge gotcha.

As a final note, all this is subject to constant evolution. Things change in the blink of an eye and it’s a full time gig to maintain consistent cross border remittance with small factories. We receive daily updates from our logistics providers outlining rule changes.

Sorry to geek out on this :slight_smile: I spent nearly a decade living in Shenzhen, opening multinational companies and acquiring permits, it absolutely consumes me :squinting_face_with_tongue: I’m always too happy to share way too much about cross border RMB remittance.

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Hi @ian , Thank you for responding so quickly. The detailed information is much appreciated. I’ve reached out to Ru, via the “Contact” link at DirtyPCBs.com. I hope I will hear back soon.

We have had good experiences in the past developing relationships first via Alibaba, then direct. So far, our experience with small to midsize Chinese manufacturers has been very good. However, we have been unable to identify a factory that could custom mill these parts with initial test runs of a couple hundred pieces.

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