Moteino/production board testing – IDE vs. avrdude

To those that have concerned over the utility of my IDE add-on’s utility, I would like to follow up and give an example of production board batch testing at a very simple level. A simple pogo (spring loaded probe) jig is used to only power and access essential peripherals of a target board, and among other things upload a fixed test sketch to ensure basic functionality of the board. Since this is done repeatedly, it’s desirable to have a more automated way of doing this over and over again to save time. I show how we can edit some IDE settings for a target board to skip verification, and also how you can use avrdude to quickly upload sketches without the IDE’s compilation and optimizations overhead. The same would apply for bossa for SAMD or whatever upload tool your target board might be using). Let me know your thoughts and suggestions!

As an update – I’ve always just used avrdude for quick uploads but a very worthy mention suggested by a viewer is using avrdudeSS which is a very nice GUI for avrdude, check it out!

Component sourcing and Mouser vs. Digikey Pros and Cons

This post is about mainly sharing the experience of a small maker business sourcing genuine components right here in the USA. Sourcing and stocking the right components in the right quantities is one of the finest balancing acts in a small electronic manufacturing business. That’s because keeping large stocks of parts has not only tax implications but also drains funds from other efforts faster than you may realize. If you’re a beginner and need some tips, here’s some experience that might save you a little sweat and hopefully a few of your hard earned dollars. I might will update this article in the future as more things come to be realized in this area of the business.

My main parts suppliers since LowPowerLab‘s inception were Mouser and Digikey. Both are great in their ways which I outline down below, but there have been some surprising downside quirks as well. Hey it’s a little hard to get motivated to write only about awesome things, usually the bad stuff triggers reviews. But I’ll try to keep this objective and informative. If both were great at everything then there would be no reason for competition or even having multiple suppliers. Monopoly is a bad thing in supply chains, and I hope these companies will continue to exist as separate entities and not eat each other in some monster acquisition deal.


I have mainly 2 types of orders. One type is the “small value” prototyping batch of components or small run custom batch for a client which I usually place at Digikey due to their more comprehensive offering. Even this can run into the lower hundred dollar range depending on the project I’m putting together, but the average is under $100. Then there is my normal run, what I call the periodic replenishing orders which are in the thousands of dollars range. Whenever I run low on certain parts, I place them in the cart, and they stay there until I’m ready to complete the order. It’s unlikely for me to use fast shipping, so I usually go with ground services. I even use USPS for the real low count prototype orders.

Before I get into my sourcing experience with these suppliers, let’s take a quick look at the pretty incredible state of affairs with respect to passive component sourcing in Q1/2018. So as a quick primer side story about parts sourcing – if you’re a maker you’re already familiar with the astronomical passives lead-time situation. Just the other day I was scrambling to find 0.1uF 0603 caps (which along with 0603 1K 10K resistors are the most popular and numerous parts in my designs). They  nowhere to be found these days due to extreme factory lead times for new passive stocks. I ended up paying $210 this week for the last 15K reel of cheapest 0.1uF caps (normally <$20 for a 4K reel). Yup, it’s that bad!

Neither of these companies are directly at fault for this, at least not for the supply chain. But they control their dwindling stocks pricing of course that’s for sure, and why not make a buck while in this dire straits, right? This week I made the mistake of keeping some reels of basic passives in the cart for a day or so until I completed my order (at Digikey first then at Mouser when Digikey 1) doubled the price then 2) went from a comfortable 16-24,000 parts to 0 stock. No problem, Mouser doesn’t mess with pricing right? Then Mouser did it too, but too late for screenshots to prove it! I should have just bought those on the spot knowing everyone else is trying to buy them too. Don’t procrastinate silly!

Anyway let’s now go ahead and imagine a little fable here:

In general as companies (not necessarily these) get larger they tend to become more imperialistic, trusting their dominance on market share confidence and getting preferential with customers depending on their bottom line impact. Small customer care becomes secondary. Me and you are probably lost in the background noise of annoying small customers, more so the lower the order value (more overhead per order for less profit!). Say you bought a few different SMD resistors, some switches, whatever else small value components for your latest breadboard project.

You buy not-overnight shipping, place your order sometime in the morning and expect them shipped in cut tape or whatever part spec packaging, before the same-day shipping 8-9PM cutoff time, well in time to get it for your exciting weekend project you’ve been looking forward to. But hey wait – who cares about your $19 order value, when there’s real customers. Think someone will walk the warehouse 5 minutes to count and cut your 10x 0603 resistor tape then pack your $19 order by cutoff time just because your order came in early? Have a question or concern? Go away annoying fruit fly, we are having some difficulties fulfilling the unexpectedly large number of orders in the last day, we will get to your order after the real customers and our interests get served.

That fable is a little on the extreme. But it get’s pretty close to reality actually when it feels like it’s happening to you, again, then again, and again. Continue reading

New solder station: METCAL MX-5200

For the past few years I’ve been using this XTRONIC 6000 series solder station which cost around $120 and I picked it because it was compact and it included hot air which was always very useful for SMD reworking. I (ab)used it and it soldered many thousands of parts at Low Power Lab. Needless to say, you always get what you pay for. The iron, would take about 1 minute to be ready for work, and for lead-free soldering I would always keep it at the maximum 480 degrees (Celsius?) and it would still take forever to heat up joints that have lots of metal mass or are part of a GND pour. And the tip being always on, it would gradually deteriorate and would need changing from time to time. But hey, for the money I spent, I think it paid for itself many times over.

So … it’s time for an early Christmas solder station upgrade. I know METCAL is the way to go and the obvious choice was the MX-5200 Smart Heat System which allows 2 independent outputs. Since this particular kit only includes the hand pieces and stands, and not any tips, I bundled some of these lead-free tips (STTC-125) and also two wide blade tips for easy desoldering of wide packages (for effortless removing of radios from Moteinos). These blades alone cost more than my previous station, doh. One mistake I made in my initial order was I ordered the wrong tips for lead-free (STTC-525) and although they claim to be “lead free compatible” they would not melt lead-free solder. When all was said and done, this came to around $1200, but was it worth it? I wanted to write about this upgrade and share my experience.

Here’s a shot of the unboxing and compared to the old station – which I will keep for the hot air.

I’ve used the METCAL station for about 2 weeks and if there was 1 word to describe it … I would choose “amazing”. It feels like I just took a giant leap. It just works and it makes you love it every time you use it. Yeah it’s pricey but when it gives you that almost instant endless heat and makes your solder job go fast and flawless, you start to appreciate the price tag. I won’t do a teardown to bore everyone (do people still watch 1 hour long teardowns?) and it might void the 5 year warranty. There’s a great video walkthrough below that I think is well made and to-the-point and illustrates the essentials and capabilities of this tool:

To summarize, here’s what I love about this tool (just about everything):

  • it heats up FAAAAAAST!
  • melts any solder joint instantly, even those large GNDs are effortlessly melted, no more soldering frustration. The LORA modules used to be a bit of a pain to solder because their GND pads were part of the GND pour with no thermal relief, with the METCAL they solder as fast as any other pad
  • hand pieces connectors go in and out the station ports without the need to tighten the optional nut
  • hand pieces are so light they feel like a pen, and your hand is very close to the working spot, making it feel up close and giving your hand more precision:
  • there are no dials, no temperature selection or anything like that, just turn it ON and it takes care of the rest. It sends just enough heat to do the job and when it feels there’s more heat needed it spikes more energy to that particular port. It’s called “Smart Heat” after all and it seems to do a great job.
  • there is a single button that just selects between LEFT, RIGHT or BOTH ports, this way you can have both plugged in, and only heat the one you need, then switch, or use both when you need to rework something.
  • when seated in the rests, the heat is minimized to help preserve the tip.
  • “plug and play” hot swap tips … they plug in and out effortlessly with the included rubber pads. The station detects when a tip is removed and plugged back in and only applies heat appropriately.
  • the station is very hefty and solidly built, doesn’t have that flimsy plasticky cheap feel to it, this is not a toy.
  • has many other accesories and hand pieces that go with it for a complete soldering/desoldering/rework lineup.

Expensive tools are always hard to justify, some people like to say. But I argue they are in fact FREE. Read on. They are hard to justify unless you use them every day. Then you want the best you can get so that the tool doesn’t stand in the way of your work. Just saving 10 seconds a solder job will add up to several hours in a year. If your time is worth anything, then a tool like this will pay itself within just 1 year, in time and neurons saved. After that it becomes free. See how expensive tools are actually free?

Enough already, I think I made my case. This tool is awesome, if you got the budget or long planned to, get it, today, you will love it. It will give you pleasure to work with this tool, and step you up that professional ladder. Plus it’s the kind of tool that lasts a lifetime, well worth the investment.

MoteinoMEGA pick & place assembly

I spent yesterday evening assembling boards and I shot this video. It shows a closeup of the pick and place assembling a panel of MoteinoMEGAs. There are some other posts I wrote related to pick and place technology you may want to check if this is something new to you. The main things to take from this video are:

  • effective CPH (components per hour) rating is affected in large by several factors like travel from pick position to placement position, travel speed, mechanical alignment in X and Y directions, vision alignment of each board, pick retries, dropped components, feeder reloading, feeder/tape jams, and many others.
  • some components require a medium pick/travel speed and fine settle placement because they are “special” and may flip or get misaligned.

I hope I will have the patience and time to write a more in depth article and share my experience with this machine and more gotchas about picking and placing. This is still a very much entry level machine, but a semi-pro one, so I would still consider it a “real” pick and place since it can assemble a full panel with hundreds/thousands of parts without ever touching the machine.

October 2014 updates

Maybe not really obvious but a lot of stuff is going on at the humble Low Power Lab. Let me just throw in some announcements and updates:

  • Moteino R4s, MoteinoMEGAs and ATXRaspis are now coming in ENIG gold finish. This is to move towards more professional looking PCBs and to meet RoHs lead-free status. This costs a bunch more to make but instead of raising prices I actually discounted the Moteino options and will do my best to lower prices even more. I am trying hard to keep Moteino a high quality product at an affordable price for makers and businesses alike.
  • I’ve been busy putting together the requirements for my THP entry. The top 5 finalists will be announced around October 13. If Moteino Framework makes it in the finals that would be quite cool, but would put more stress on me to meet the extra criteria required by end of October.

  • One of the things I’m working on is getting a Motion-OLED shield for Moteino ready for production. Here’s a peek of it:
  • I’ve been having a blast with my new pick and place. I am transitioning all my designs to panels and adding fiducials for vision correction. I can’t help but mention that there’s a world of difference between professional machines and “DIY Open Source” type of machine that are just toys. Before getting my assembly equipment, I was doing manual assembly with a $20 modified aquarium pump and reflowing in a slightly enhanced toaster oven. Other than me physically being there I still think my previous methods were better and more productive than a lot of these makeshift pick’n’places.

    Something tells me that people are fascinated with “DIY open source pick and place machines and 3D printers” and other not really “connected” devices which was the main point of the Hackaday Prize contest. I know exactly why we’ve not seen even one such successful Pick’n’Place project, not even close, and my prediction is we will not see one too soon either based on my experience with a real one. I will expand on that more extensively in a future Pick and Place article.

  • There is a new revision of PowerShield, mostly PCB changes and making stuff more obvious to understand and use:

Moteino Framework architecture decisions

My vision for Moteino was to create an affordable/open/ideal/easy hardware platform that would fuel a new generation of wireless internet-of-things, and I think it came out pretty decent. My Hackaday Prize entry even made it in the top 50 semifinalists (out of 800+). More devices are being added to the Moteino Framework and existing ones are being improved to make it fun for those makers who like to DIY and solder their internet-of-things from easy to assemble kits. The end users have maximum freedom as far as using/building stuff with Moteino. They can build absoltely everything from scratch, as some have done, but some prefer to just save time and buy building blocks. Hence I funded my way through this adventure by selling ready made Moteinos and kits in my webshop.

People have asked many times why the Moteino was designed the way it was, and why not use this and that and the other type of MCU, transceiver type, radio band, or wireless technology. The number one reason why Moteinos are what they are today is because in the end they need to be designed to manufacture, work well, be reliable, license free, easy and fun to use in a friendly board format, cheap to buy or make, achieve long open air range or excellent indoor obstacle penetration when used with transceivers, etc. Here is my reasoning behind all these decisions and the answers to some frequently asked questions. Continue reading

Lasercut strip feeder for your pick & place

Got pick & place? Cool.
Got cut strips components but no strip feeders? No? Then this post is for you.

Problem: You need to assemble a small run of boards in your pick and place and buying full reels of parts makes no sense, instead you get a low count in cut strips. Strip feeders cost a lot, and they are not very special, just cold dumb metal. Of course, the manufacturer will sell you high quality feeders machined from aluminum/steel, but placing components from cut strips that already have pockets spaced evenly sounds like a very easy problem right? I mean you could just stick them on a cardboard with double sided tape and then teach the machine the first+last and it figures out the rest. That works but it’s a pain when you need to reload – you have to re-teach the machine since you won’t stick it exactly in the same place, you’re almost better off placing by hand.

Solution: So let’s make a strip feeder. I have lots of components that are less than a full reel (exotic resistors, transistors, crystals, caps, mosfets etc). Most of these are 8mm and 12mm tape, rarely 16mm. So it would be perfect to have a strip feeder that can be placed in a fixed position in the machine. To reload you just cut the pre-determined length, feed it through and align the first pocket to a marker on the side, reset component count for that row, and machine already knows where to continue, quick and easy. Continue reading

Pick and place – commercial options

HDR_2This post is a follow up to the “pick and place” category of articles, if I can call it that, I am trying to keep my promise of discussing some commercial pick and place machines. I researched for a good entry level (non DIY/kit) pick and place machine that could cover assembly needs without a lot of baby sitting. I am not talking about high end machines here, but something like what Adafruit or Sparkfun first got into, something suitable for a startup both feature/budget-wise. Even these entry level commercial machines are easily in the tens of thousands of $. You can easily spend twice what you’d pay for a brand new reliable car. I don’t know about you but when I think of spending that kind of cash I’d want to do my homework and know everything I can possibly expect from the product. This article is not meant to be exhaustive but I hope to cover most concerns and give a good idea what is important to look for, I can only wish there was a concentrated resource like this when I first started my research. It’s a long writeup but I hope those interested in the subject will appreciate the aggregation.

First let’s look at some of the things I learned along the way, and the features you may run into or want to consider. Then we’ll look at some of the available machines and discuss pros and cons. Continue reading

Pick and place – entry level options

Startups that manufacture electronics are faced with a limited set of choices when it comes to getting their hardware assembled. Each of the methods below have an array of possible approaches, some good some less so. I will try to cover what I’ve seen in my quest, hoping this will be a good overview of what’s out there. If I miss details or interesting methods please let me know and I will keep this list updated. This is part one, where I look at options of assembly without getting into a real commercial pick and place.

Doing it manually. Everybody started here, including Adafruit, Sparkfun and others. It’s great and fun at first and you learn a lot about surface mount technology (SMT) and also gain respect for how hard quality assembly really is. And we’ve seen countless ways people do this around the world. Some spread paste with a toothpick or dispense with a DIY syringe, then place parts with tweezers. This works for about 5 minutes before you go crazy, especially if you go smaller than 0603. Others laser cut mylar stencils to speed up the paste deposition. I etch my own stencils from soda can aluminum, this is fast and works great. For placement I’ve seen people make some fancy ball bearing jigs to help them move their hand, a bit better.

This is very cool and I almost did this myself but I think it’s overkill and a bit slow and … more expensive than it needs to be for what it does, but I can appreciate the effort of its creator. One advantage of this fixture is the ability to better hover over larger PCBs while placing. FWIW the maker even went as far as mounting a camera to help placing the parts, a nice touch, but looking at his video of it in progress the angle of the camera looks weird and looking away on a monitor when you work with your hands is what cuts the speed. Here’s another one of the same kind for reference. I do the same as these, only probably faster, with my aquarium pump pick and place (hold your laugh for a moment there) which cost me about $20 in parts, took about 30 minutes to make, and has full stereo vision – my eyes, can’t beat that for the price. I like to brag about this method not because I’m using it, but because it’s probably the best 100% manual method I’ve seen. Why you ask? I can do up to 7-800 CPH (measured!) with it on less complex boards. The only downside is obviously having to sit there all the time, with some neck and back strain, and the part alignment is less than ideal, but paste reflow really helps. I’ve assembled many thousands of PCBs this way, it works nicely and gets stuff done, but it’s not great. I wish I spent all that time developing new projects. So what is better than this?

Continue reading

PCB trivia – can you spot the short?

Ah the joys of manufacturing …

This one drove me crazy, no short at a close inspection. But I was determined to find it. I ended up desoldering almost all components off thinking the short is under some cap or resistor, but the short was still there. I had to pull the microscope to track it down. Here’s a shot of the PCB through the scope. Can you spot the short?