by Diodes Delight

A tiny-but-mighty open-source carrier board for the Raspberry Pi CM4

View all updates Sep 25, 2021

Approaching the Finish Line

by Timon

It’s been a stressful few weeks, but we are getting close to the finish line. Like last time, there’s some good news and some bad news.

The good news is that PCBs were delivered to my manufacturer about a week ago. They have been delayed a bit, they should have arrived in the first week of September, but as things go, in these times of shortages and supply chain disruptions, they couldn’t be finished in time.

I also received the mass production run of the packaging, labels and other misc. things that have been produced at other manufacturers.

A special treat for early adopters has also been delivered to my manufacturer for packaging. A very shiny holographic sticker of the Diodes Delight logo. They look absolutely delightful!

Now to the bad news. Over the past few weeks, I have mostly been busy dealing with regulatory matters regarding CE, which has been quite stressful to say the least. Unfortunately, this has cost me a lot of time and effort, and had delayed work in other areas.

On top of that. I got notice early last week from my manufacturer that they can not guarantee automatic optical inspection will catch all solder defects that might occur on the high density connector the CM4 uses. They have experience with the connector in other projects and estimate a 5% defect rate after AOI. Fixing such defects is easy, but of course they need to be caught!

While I wish I had gotten notice a bit sooner, I’m glad they talked to me about it, a lot of manufacturers will just silently go ahead or simply don’t really care.

As a consequence, I was scrambling last week to design an electrical tester for this. The PCB has been produced already, and should be on the way to my manufacturer for assembly. This was fairly tricky and is something I really wanted to avoid. I might go into technical details about that in another update.

This is the last thing standing in the way of finishing production and packing everything up to ship to the Mouser warehouse.

Unfortunately, the timing for this is not great considering last week was a national holiday in China, where all manufacturing for Piunora is happening, and the fab was closed for three days. Then, starting October 1st is a another week long national holiday. This gives us effectively seven working days to get everything assembled, tested and shipped out. Which is just not going to happen without crazy crunch time on all sides.

I’m a big proponent of ensuring reasonable work hours, not only for myself but also for my manufacturer, so I will not push unnecessarily to get things out just to meet the previously set October 11th deadline for shipping out the products to all of you.

I’m sorry things are getting delayed once again, but I’m hopeful we are getting close now.

So is there anything else that can go wrong from here on out? Well yes, production could still experience some unfortunate events. Though I have been producing with Makerfabs (my manufacturer) for many years, and they have so far been doing an excellent job.

I could see that the electrical tester might have some early firmware bugs, and will need a bit of debugging before it can reliably test all Piunoras, so that could eat up some more days.

Then its off to packing and shipping things to the US. Importing goods is always a tricky thing, and customs could give us unexpected trouble. I will make sure everything is as prepared as it can be, but customs can sometimes be unpredictable, especially in these times. So this can be a big unknown that can ruin any product launch’s day.

Because this is a variable that I just can’t really control, I will set the estimated shipping day cautiously to 7th December. I will keep you regularly updated on the state of production and shipping as always. Fingers crossed that we will make it to the finishing line unscathed!

About the Author


timonsku  ·  timonsku

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Product Choices


Piunora Pro

A compact, feature-rich CM4 carrier board


Piunora Lite

Perfect if you need the slimmest possible form factor. Includes all features of Piunora Pro except for the camera connector and the PCI-e M.2 port.


M.2 B-Key 2280 Extender

Expands Piunora's M.2 port to accommodate full-length 2280 peripherals. Keep in mind that such devices are quite a bit longer than Piunora itself, so they might look a little awkward hanging off the end there. But, if you have a cool idea that depends on a 2280 M.2 accessory...this is the product for you.


Raspberry Pi CM4 (Lite, Wireless, 1 GB RAM)

From the Crowd Supply Basics project.

Something for your Piunora to carry.

This CM4101000 variant of the Raspberry Pi Compute Module 4 is a System on Module (SoM) containing an ARM quad-core Cortex-A72 processor, 1 GB RAM, 2.4 and 5 GHz 802.11b/g/n/ac Wi-Fi and Bluetooth 5.0, and supporting power circuitry. Does not include eMMC flash.


Raspberry Pi CM4 (8 GB eMMC, Wireless, 2 GB RAM)

From the Crowd Supply Basics project.

Something for your Piunora to carry. The Piunora microSD card does not work when using eMMC CM4 variants.

This CM4102008 variant of the Raspberry Pi Compute Module 4 is a System on Module (SoM) containing an ARM quad-core Cortex-A72 processor, 2 GB RAM, 2.4 and 5 GHz 802.11b/g/n/ac Wi-Fi and Bluetooth 5.0, 8 GB eMMC flash, and supporting power circuitry.


Heatsink for CM4

You can operate the CM4 without a heatsink just fine, but if you have some extra-heavy computation to do, then a heatsink can help prevent thermal throttling of the SoC. Includes a mounting footprint for a 30 mm fan (not included) should you want to integrate it into an enclosure or take your CM4 to even greater extremes of computation. Also includes a set of stacking pin headers to accommodate expansion boards.


microSD Card

From the Crowd Supply Basics project.

Boot media for the "Lite" (CM4101000) variant of the CM4. We recommend 64 GB or smaller.

An industrial-grade memory card with extended endurance.


RPi CM4 Wi-Fi Antenna Kit

From the Crowd Supply Basics project.

An omnidirectional 2 dBi gain 2.4/5 GHz Wi-Fi antenna with panel-mounting hardware and an approximately 7.5" (19 cm) cable to connect the antenna's SMA connector to the CM4's U.FL connector. It is "certified for use with the Raspberry Pi Compute Module 4".


Diodes Delight

An open source hardware company and consultancy

Timon Skerutsch



PCB Fabrication & PCB Assembly

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