Fail of the Week: OpenMV Kickstarter Project Hits Manufacturing Snag

Making stuff is hard, especially when you are making lots of stuff. The OpenMV Cam project knows this, because it has hit a problem while putting together their cheap machine vision module. The problem is with the BGA solder balls that connect the image sensor to the main board.

openmv-thumbWe’ve covered this intriguing project before: the aim is to build a small, cheap module that can run image processing algorithms to easily give robots sight. The sensor is a Ball Grid Array (BGA) package, which means there are a grid of small solder balls on the back that form the electrical connections. It seems that some of these solder balls are oxidized, preventing them from melting and fusing properly with the board. This is called a head-in-pillow defect, because the ball behaves like your head when you lie down in bed. Your head squishes the pillow, but doesn’t merge into it. There are 38 balls on the OV26040 image sensor and even a single bad link means a failure.

The makers of the project have tried a number of solutions, but it seems that they may have to remake the ball links on the back of each sensor. That’s an expensive process: they say it will cost $7 for each, more than the actual sensor cost initially.

A few people have been posting suggestions in the comments for the project, including using solvents and changing the way the sensors are processed before mounting. We’d like to see them overcome this hurdle. Anybody have any suggestions to quickly and cost effectively move the manufacturing process forward?

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Hackaday Links: September 27, 2015

Many moons ago, [Joe Grand] built an adapter that turns Atari 2600 joysticks to USB controllers. Now it’s open source.

Hackaday Overlord [Matt] is holding an SMT and BGA soldering workshop in San Francisco on October 4th. Teaching BGA soldering? Yes! He made a board where the BGA balls are connected to LEDs. Very, very clever.

Our ‘ol friend [Jeremey Cook] built a strandbeest out of MDF. It’s huge, heavy, about the size of a small car, and it doesn’t work. [Jeremy] has built beests before, but these were relatively small. The big MDF beest is having some problems with friction, and a tendency to shear along the joints. If anyone wants to fix this beest, give [Jeremy] a ring.

Everyone loves the Teensy, and [Paul] has released his latest design iteration. The Teensy 3.2 isn’t that much different from the Teensy 3.1; the bootloader has changed and now USB D+ and D- lines are broken out. Other than that, it’s just the latest iteration of the popular Teensy platform.

The DyIO is a pretty neat robotics controller, a semifinalist for the Hackaday Prize, and now a Kickstarter. The big win of the Kickstarter is an electronics board (with WiFi) that is able to control 24 servos for all your robotics needs.

[pighixxx] does illustrations of pinouts for popular electronics platforms. Everyone needs a hobby, I guess. He recently put together an illustration of the ESP8266. Neat stuff is hidden deep in this site.

You would not believe how much engineering goes into making snake oil. And then you need to do certifications!

[David] identified a problem, created a solution, got a patent, and is now manufacturing a product. The only problem is the name.

Creating New Nintendo 3DS Hardware

For the last five years or so, Nintendo has been selling the 3DS, the latest in a long line of handheld consoles. Around two years ago, Nintendo announced the New Nintendo 3DS, with a faster processor and a few other refinements. The new 3DS comes in two sizes: normal and XL. You can buy the XL version anywhere in the world, but Nintendo fans in North America cannot buy the normal version.

[Stephen] didn’t want the jumbo-sized New 3DS XL, both because it’s too large for his pockets, and because there are no fancy cases for the XL. His solution? Creating a US non-XL 3DS with god-like soldering skills.

In manufacturing the XL and non-XL versions of the 3DS, Nintendo didn’t change much on the PCBs. Sure, the enclosure is different, but electronically there are really only two changes: the eMMC storage and the Nintendo processor. 3DS are region-locked, so simply swapping out the boards from a normal 3DS to an XL 3DS wouldn’t work; [Stephen] would also like to play US games on his modded console. That leaves only one option: desoldering two chips from a US XL and placing them on the board from a Japanese 3DS.

With a board preheater and heat gun, [Stephen] was able to desolder the eMMC chip off both boards. Of course this meant the BGA balls were completely destroyed in the process, which means reballing the package with solder bits only 0.3mm in diameter. With the US eMMC transplanted to the Japanese board, [Stephen] ended up with an error message that suggested the processor was reading the memory. Progress, at least.

[Stephen] then moved on to the processor. This was a nightmare of a 512 pin BGA package, with 512 pins that needed a tiny dot of solder placed on them. Here, sanity gave way and [Stephen] called up a local board and assembly house. They agreed to solder the chip onto the board and do an x-ray inspection. With the professional rework done, [Stephen] assembled his new US non-XL 3DS, and everything worked. It’s the only one in the world, and given the effort required to make these mods, we’re expecting it to remain the only one for a very long time.

Circuit Printer Doubles as a Pick and Place

Squink PCB printer and Pick and Place

Prototyping circuits is still a pain. The typical process is to order your PCBs, await their arrival, hand assemble a board, and start testing. It’s time consuming, and typically takes at least a week to go from design to prototype.

The folks at BotFactory are working on fixing that with the Squink (Kickstarter warning). This device not only prints PCBs, but also functions as a pick and place. Rather than using solder, the device uses conductive glue to affix components to the substrate.

This process also allows for a wide range of substrates. Traditional FR4 works, but glass and flexible substrates can work too. They’re also working on using an insulating ink for multilayer boards.

While there are PCB printers out there, and the home etching process always works, building the board is only half the battle. Hand assembly using smaller components is slow, and is prone to mistakes. If this device is sufficiently accurate, it could let us easily prototype complex packages such as BGAs, which are usually a pain.

Of course it has its limitations. The minimum trace width is 10 mils, which is a bit large. Also at $2600, this is an expensive device to buy sight unseen. While it is a Kickstarter, it’d be nice to see an all in one device that can prototype circuits quickly and cheaply.

An Amazing DIY Single Board ARM Computer with BGA

DIY Single Board Computer ARM

Typically, you buy a single board Linux computer. [Henrik] had a better idea, build his own ARM based single board computer! How did he do it? By not being scared of ball grid array (BGA) ARM processors.

Everyone loves the Raspberry Pi and Beagle Board, but what is the fun in buying something that you can build? We have a hunch that most of our readers stay clear of BGA chips, and for good reason. Arguably, one of the most important aspects of [Henrik’s] post is that you can easily solder BGAs with cheaply available tools. OSH Park provides the inexpensive high-quality PCBs, OSH Stencils provides the inexpensive stencils, and any toaster oven allows you to solder even the most difficult of components. Not only does he go over the PCB build, he also discusses the bootloader, u-boot, and how to get Linux running.

Everything worked out very well for [Henrik]. It’s a good thing too, cause we sure wouldn’t want to debug a PCB as complicated as this one. What projects have you built that use a BGA? Let us know how it went!

Shenzhen Tour and UnHuman Soldering Classes with DP


If you’re free the first week of April and don’t mind sitting on a plane for a looooong time you should check out the Hacker Camp that Dangerous Prototypes is planning. We’re sure you remember [Ian Lesnet] who is a Hackaday Alum, creator of the Bus Pirate, and geeky world traveler. Now’s your chance to try out what to him is a way of life.

The event is April 3-5 in Shenzhen, China. Although marketed as a “Hacker Camp”, to us it sounds more like training for those interested in running hardware companies that use the Shenzhen manufacturing district as the anchor of their supply chain. Part of the prep-work for the trip includes submitting board files which will be fabbed and ready for you on the first day. [Ian] and his crew will be your guides for the culture of the area; complete with meals and bar time. But there are also soldering workshops as part of the package. Don’t pooh-pooh the idea. This is unhuman soldering… BGA and QFN soldering instruction from the people who repair cellphones and other microelectronics.

This [Rick Steves] style adventure is the first that we remember hearing about that targets the open hardware community. But we must admit, it sounds like a lot more fun than a European river cruise!

[Thanks Akiba]

Hand soldering BGA wafer chips


And here we’ve been complaining about Flat Pack No-Lead chips when this guy is prototyping with Ball Grid Array in a Wafer-Level Chip Scale Package (WLCSP). Haven’t heard that acronym before? Neither had we. It means you get the silicon wafer without a plastic housing in order to save space in your design. Want to use that on a breadboard. You’re crazy!

Eh, that’s just a knee jerk reaction. The wafer-level isn’t that unorthodox as far as manufacturing goes. It’s something like chip on board electronics which have that black blob of epoxy sealing them after the connections are made. This image shows those connections which use magnet wire on a DIP breakout board. [Jason] used epoxy to glue the wafer down before grabbing his iron. It took 90 minutes to solder the nine connections, but his second attempt cut that process down to just 20. After a round of testing he used more epoxy to completely encase the chip and wires.

It works for parts with low pin-counts. But add one row/column and you’re talking about making sixteen perfect connections instead of just nine.