This post was originally written on Hackaday, 02/21/2025 at 11:24:
Once all the components spent their time in transit and were all collected on my workbench, I decided the first order of business was to dry-fit everything together; it wouldn't do if any of the parts I ordered were off or mis-sized, either by fault of my own design or otherwise!
First up, the plates:
here you can also see a comparison between JLCPCB's default matte black, and PCBWay's default shiny black. I was a bit iffy about the shiny black to start with, but it's grown on me.
so far so good!
The next part is where it gets tricky.
In order to dry-fit the more interesting 1U and 2U parts, I'm going to need to assemble the adapters I designed. The screws for them haven't arrived yet, but I ordered some other not-quite-as-nice ones from my local hardware store, and they will do for now.
I designed each of the parts such that they would be quite tight, but even so I did need to take a small file to them to get them to fully fit together. If I were to re-design them, I would add areas into the inner corners of each of the fingers to make sure the mill didn't leave too much material in between them. Thankfully, they didn't need much filing, and after a few attempts, they went together nicely.
Lining the two parts up with some blu-tac to hold it all together while I work, I first soldered just one corner on, then the other, and when I was happy with the angle I finished the middle sections.
Humble beginnings.
PCBs have a bit of slack in them, and I took advantage of that as I worked the corners. I could finish one corner, check the angle of the plates, and bend the other corner into shape while the solder was hot, then simply re-heat the opposite corner to release the stress.
I designed many separate PCB-Attachment sections into the design because I wasn't sure if one single large slot would work, in terms of being able to heat it all up with my soldering iron while the solder melted into place, but I also kept in mind that the very tiny (1.25mm) slots might be too small to bother doing individually. I played around with a few combinations until I found one that worked nicely for me, which ended up being sets of 3 soldered together with one set between each. This was much easier to solder, and not too finicky to deal with.
Lining them up on the table once they were done, I could get the screws tightened on the rails and make sure they were tried and true. The PCBs were nice and strong, and the rails light, so they didn't need much tightening, and all in all it was fairly painless!
I then put the rails into the case, and made sure they fit, and.. oh that's really quite nice, isn't it?
Maybe I will mention this in the Eurorack community, I'm sure someone would love a nice homemade alternative to some of the 3U-to-1U adapters, especially one as flexible as this! Just order the lengths you want, and solder it, and it's done! Perhaps I will do this alongside the publishing of this log update.
Anyway, now that I have the rail adapters done, I can screw in each of the individual electrical components into their respective PCB plates, and this is what that looks like:
Oooh isn't that just pretty!
It's got the sauce, as the kids say.
I'd post that to my aesthetic tumblr under #tactile.
actually, I might just do that too brb.
I had the idea for the implementation of the tracking screen after I caught a cold visiting my old hackerspace in Berlin, c-base and had to spend some time in bed. I thought it would be cool to be able to have a robotic screen that tracks faces and can be moved around to other positions via hand commands.
Thanks to pcbway this project is now becoming a reality and once the final parts arrive I'll finish up the final product and documentation. It's based on a waveshare camera and should be fairly easy to reproduce with the guide. Looking forward to the release.
Since Raspberry Pi's launch in 2012, it has been sold 30 million worldwide in the eight years. The reason why Raspberry PI gains many fans in the electric area because it aims to make and sell inexpensive, single-board computers that are easy to use and ultimately become tools to boost people’s interest in computer programming.
Let’s enjoy some DIY Raspberry PI projects made by our PCBWayers!
This week we celebrated the first birthday of my youngest son, Luca. So it is time for him to blow out his first candle. Of course you can't trust a one-year-old to not set the house on fire when handling a candle, so of course we need to solve this with some electronics.
Obviously the only solution to this problem is building a sound responsive fake candle which Luca can blow out. We only need to throw together a MEMS microphone, an amplifier, a microcontroller and some fire-colored LEDs. Easy. Right?
The schematics are mostly based on Sprakfun's MEMS Microphone Breakout. I swapped out the ADMP401 microphone for the INMP504, since the ADMP401 is no longer available. The charasterictrics of the INMP504 are the same so I didn't need to adjust the schematics for this change.
The audio signal which is amplified by the OPA344 opamp goes into the ADC of the AtTiny85 microcontroller, allowing me to measure the volume of the sound. Blowing into the microphone generates a loud noise which will trigger the power-off function of the microcontroller and the LEDs.
With the help of KiCad 5.1 (Which, by the way, is an awesome update) I designed a PCB the size of a standard 40mm tea light. The small hole next to the LED's is the sound port for the MEMS microphone which is placed on the other side of the PCB.
The back side houses most of the parts together with a CR2032 battery holder.
After the tiny INMP504 MEMS microphone arrived I was somewhat intimidated by its small size. A great part to test my SMD soldering skills. Next to the INMP504 is the SOT23 OPA344 opamp which isn't a whole lot bigger. This is going to be fun!
After I finalized the design and check all (BUT ONE!) of the footprints, I ordered the PCB's at PCBWay. The quality is pretty good, although the silk screen is a bit offset. Not a big deal, but not perfect either.
After I painstakingly applied some solder paste by hand and placed all the tiny parts, the board was ready to dance on my hot plate.
The result (after a bit of touchup using my hot air soldering iron) looked pretty decent.
See that little botch wire at the button? Yeah, that button was the only footprint I didn't check ... sigh
Using some test code I checked if the LED's worked. By default running PWM on the ATTiny85 is only available on two PWM ports at the same time when you use the Arduino framework. But with the help of some sample code found on Technoblogy.com I quickly got all three LEDs up and running.
And now for the fun part! By reading the analog port and defining a volume-threshold on which the the LEDs should turn off, I'm able to "blow out the candle". I wasn't sure if this would work. Especially since I wasn't able to check the soldered connections of the tiny MEMS microphone. But lo and behold ... IT WORKED!
Initially I only turned off the LED's. But since the button on the top is bound to the reset port of the ATTiny85, I could put the microcontroller to sleep as well. Better yet, as you might have seen on the PCB, I've added some jumper pads. this allows me to change the power input of the microphone and opamp from VCC to the spare pin of the microcontroller. This allows me to cut off the power to the microphone and amplifier whenever the candle goes in power off mode.
The result! 0,5uA after I blow out the candle. This way Luca can easily reuse this candle and battery until his 30th birthday. Right?!
Of course, my 1 year old son will not be fooled by three little SMD LEDs, so I need to work on the packaging a bit. Some hot glue and a few blisters on my fingers is all I need to make a few convincing flames.
The best part of using hot glue for this, is that I only need a little bit of heat to fix it to the PCB.
With the help of my 3D-printer I made a few holders to finish it off. I think I made come damn convincing candles!
So, with all this hard work done, it was time to celebrate Luca's first birthday ... Time to show my awesome parenting skills to my wife, and make this a fire-safe party!
"Are you out of your mind? Real man play with real fire!" was her response. She didn't say those exact words. But her rolling eyes and loud sigh made it absolutely clear.
So there you have it. A big birthday cake with one 5 cent candle. A candle with real fire.
Oh well ... What matters is that Luca had a great birthday party!
Congratulations little fellow! Hopefully one day we will burn our fingers together. Not with the help of a candle. But with the help of your own soldering iron.
