[NPO Tools] Upgrading the electronics lab

I’d like to see us upgrade the electronics lab into something useful for targeting modern PCB type projects aka surface-mount dominated instead of through-hole dominated.

That means the addition of some things to the space.

  1. Oscilloscope

This is probably the most important consideration. Leaving aside whether the old analog scopes work, modern systems all have interface buses like UART, SPI, I2C, etc. That requires a digital scope to decode.

There are lots of options: standalone, USB-based, tablet-based.

In my opinion, the two key features on a scope to be useful for hobbyist work are 4-channels and 100MHz. SPI decode requires 4 channels. 100MHz bandwidth barely captures 33Mhz signals (3x the fundamental frequency) but 33MHz is normally pretty fast for hobbyist signals. 5x would be better, but the jump to 200MHz is a significant enough price bump that you could buy a second scope.

I’m a standalone snob. :slight_smile: However, the standalones have several points that I consider advantages in that they don’t require a paired computer, and they tolerate slightly higher voltages and misconnection better. If you tie a USB-scope ground to a solid 20V source, probably the scope and the computer are dead. If you tie a standalone ground to 20V, your circuit will likely vaporize instead.

I would probably go with a Instek GDS-1104B. That’s about $650-$750 and some places offer EDU pricing which we might be able to get. They hit the specs I laid out, and they transfer to PCs faster than most of the other choices.

However, I’m not wedded to this decision and am happy to discuss with people if they think there is something that meets our needs better.

  1. A Metcal soldering station (at least one)

Yes, we have Hakko’s. They’re okay. I used them personally for a lot of years.

And then I got a Metcal and my soldering got WAY easier. Don’t get me wrong, my soldering still sucks, but at least now I could at least make tiny 0402 components functional if not pretty. And I could solder big transformers because they finally got enough heat at the tip.

I can go into why Metcals are better technically if people want (careful … I will bore you to tears about curie points and power transfer), but the Metcals have two particular advantages for a hackerspace: the tips interchange easily without tools and they never need calibration. The tips are about $20 each and people who really care would probably purchase and carry their own.

The power brick (MX-PS5200) new is $600, but they regularly pop up on eBay for various prices and used is generally perfectly fine. The handpieces (MX-H1-AV) are about $140 new and do also pop up on eBay–used is a mixed bag. Someone with more patience than me at dealing with fleaBay and returns on suboptimal stuff could probably score something good.

We already have a microscope and it’s optics seem fine, but the ring light needs to be repaired or replaced. We need to refresh some basic materials/chemicals (see #5)

That would put the lab in a state that people could do stuff like hand solder up single boards ordered through OSH Park or hand solder up kits from Adafruit.

To be able to do multiple boards, we need a touch more tooling:

  1. PCB Solder Paste Stencil Printer

These are what you use to put solder paste on your boards with your $100 framed stencil. This is a good example (CAUTION: Alibaba link. Chinese E-Commerce site with all that implies. Surf with Javascript blockers. You have been warned.) Alibaba PCB Solder Stencil Printer

Those are generally in the $300-$350 range depending upon phase of the moon. They work. That’s about all you can say.

  1. PCB Reflow Oven

Whoo boy. In the middle of a hackerspace this is likely to be contentious.

At work, we bought a Qinsi QS-5100 from Alibaba. Those appear to no longer be made or all appear to be counterfeit, now. The difference between that one and the T-962(A,B,C,whatever) was the number of heating elements.

It appears that the T-962C is the closest equivalent nowadays-and it appears to be total garbage. So, it’s back to the venerable T-962A which has had a couple of upgrades. $350 and change.

As hackers, though, there is another option at about the $500 price point. You can build a decent one of these out of a convection oven and a controller:

Convection Oven PCB Reflow

Convection Oven PCB Reflow Pictures

That’s quite a bit of Reflect-a-Gold and Hi-Temp insulating blanket. Both are quite annoying to work with.

Can you go cheaper? Sure. But then you’ll spend more time piddling with your oven than building your boards.

There is also another really hacker option. It’s called “Vapor Phase Reflow” and it uses a thermal transfer fluid called Galden (I use Galden HS240, if I remember correctly–I’d have to go look up the receipts). At some point after Covid I may shoot a video about that. It has the downside that you now have a per batch cost to your boards (about $10-20 per batch), but the upside that your boards come out fantastic, and you don’t have to dork with the Chinese reflow oven profiles.

  1. Small refrigerator

Solder paste in particular needs refrigeration, and you don’t want people putting food in with it (eating metal–even if it’s Tin-Silver-Copper solder–generally isn’t exactly healthy). A small peltier thing is probably the right size and wouldn’t have the capacity to risk someone stashing their beer and getting it contaminated. :slight_smile:

  1. Chemicals and sundries

These surprisingly add up more quickly than you expect.

  • Flux Remover
  • Paste Flux
  • Basic Solder
  • Solder Paste
  • Acetone
  • Lint Free Kimwipes
  • Acid-free brushes
  • Canned air
  • Desoldering braid
  • Aluminum plate scrap to solder things on
  • Wire strippers
  • Tweezers
  • Magnifying lenses
  • Wire
  • Third-hand/StickVise

With that set of equipment, you can produce multiples of boards for classes or small production runs for businesses. For example, this would let you run a 10-20 person class on some Arduino project. Stencil the boards for the class, let the students populate them with tweezers and magnifiers, and reflow a bunch of them in single batches.

Feel free to suggest anything I missed.

Thanks.

We did have a digital storage oscilloscope and logic analyzer in the lab. There’s a bit of an issue with portability- one day they just walked off. But, that didn’t happen until several years in.

The $350 4ch 100MHz Rigol is a much better deal than Instek:
https://www.tequipment.net/Rigol/DS1054Z/Digital-Oscilloscopes/

The trick is they’re software-upgradeable with a code to enable 100MHz and all the protocol decoders. The code to do the upgrade is actually freely available online.

I have and love the DS1054Z and recommend. However, the probes are not the most reliable hardware out there. Have had some go flaky, but the signal quality is ok otherwise.

Even the “official” 100MHz Rigol has the ADCs overclocked, so it’s not really in spec. It’s somewhat … subpar.

That link claims that protocol decoder options are already included. Is that not true?

However, if we’re worried about it walking off, then, yes, I would get the cheaper one. Better to get a scope that we could buy again rather than one with slightly better specs.

I’ve used the Rigols quite a lot, for years. The performance is quite good. We look at 50MHz clocks going into our boards and they’re functional to see what’s going on. We have a really pricey Teledyne LeCroy too, and an older Tektronics DSO (has a 3.5" floppy slot), but the Rigols do just fine for most work. Only real complaint is some probes going flaky.

The response caused me to take a deeper look, and I stumbled into some discussion from the Dallas Hackerspace:

I then called one of my FAEs to ask about the Instek. He carries both the Instek and the Rigol and recommends the Instek as well.
https://www.gwinstek.com/en-global/products/downloadSeriesDownNew/1724/130

List seems to vary between $300-$350 (same or slightly better than the Rigol at the same point). And it has the standard controls per channel rather than the Rigol single knob for all channels (that’s actually really nice). The only loss is the subpar hack to 100MHz.

That’s probably the one I would go with.

I have a R&D build of VB-8054 that I’d be willing to loan to ASMBLY. It was going to be otherwise thrown out at my work, so I was able to take it home.

I doubt it is fully calibrated, and technically the specs aren’t warranted since it’s was an R&D build. But it has worked for everything I’ve needed it for. It should cover most if not all of the needs in this thread.

Alternatively, I know NI had provided VirtualBenches to TechShop when it was open. I can try to look into if something similar can be worked out for ASMBLY, probably at a much smaller scale. Of course that requires more effort and time to figure out :slight_smile:

That looks really awesome @azvanderpas! @EricP can set you up with a hosting agreement for it (we’re getting the docs transferred over to a new system, but should have the forms ready soon). Alternatively, if it’s something you wanted to donate to Asmbly we can get you a donation receipt for tax purposes since we’re a nonprofit now.

I also really like the idea of reaching out to NI to try to solicit some donations when someone has the bandwidth for that :blush:

That’s a nice piece of kit. Normally, NI stuff requires a license manager.

What software and computer level is needed to drive that?

I don’t believe VirtualBench requires any licensing. This is somewhat of an exception to most NI products. The software can be downloaded here.

It connects over USB or Ethernet/WiFi, and it doesn’t need anything special for a host PC as far as I’m aware. Supposedly it’ll even work with an iPad, though I’ve never tried it.