680 kit power question

[sunnybo...@gmail.com]

 I am building the 680 kit now, and have a power question.

The kit is supplied with a 9V power supply and barrel jack, but the electronics are all nominally 5V digital.

Could I replace the barrel jack with a round USB-C (5V) connector and run the kit off a USB-C power supply?

I seem be be standardizing on this setup recently, if only because of lack of wall-wart plug-in space on my  UPS. 

Thanks,

-R

[sunnybo...@gmail.com]

I also emailed Chris Davis, who let me know the Arduino Due power spec is 7-12V for the barrel jack. However if powered via the programming port, it takes 5V. Rather than change the rear plug, I built the kit "as supplied" and have already tested it with the 9V power supply (stand alone) and then later with the USB programming jack using TeraTerm. It works fabulously. A seriously nice kit!

-R

[Charley Jones]

If you read the instructions, you can’t power it from the barrel jack when connected to usb, at least, you shouldn’t.  Reading between the lines, the usb input on the back is used to power the device and get serial. So, 5v 2a should do it. Maybe 3a.  Not sure.

Sent from my iPhone 15pm!

Charley Jones, PMP

On Jan 14, 2026, at 7:45 PM, sunnybo...@gmail.com <sunnybo...@gmail.com> wrote:

I also emailed Chris Davis, who let me know the Arduino Due power spec is 7-12V for the barrel jack. However if powered via the programming port, it takes 5V. Rather than change the rear plug, I built the kit "as supplied" and have already tested it with the 9V power supply (stand alone) and then later with the USB programming jack using TeraTerm. It works fabulously. A seriously nice kit!

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[Chris Davis]

I responded to this question via email (it was sent to me as an email as well as posted here).  I'll repeat what I told him just so there's a record here for anyone searching for the same situation in the future.

The voltage recommendation for V-in on the Arduino Due is 7v-12v, with 6v being the absolute minimum.  So I wouldn't replace the barrel jack connector with a USB-C connector.  Instead, it can be powered by the micro USB power/data jack on the rear, which internally is connected to the Programming USB on the Due.  If you want a dedicated USB-C jack for power only, you could power the Due with 5v by installing a USB-C to Micro USB cable and connecting it to the Native USB on the Due.

[Gwen Patton]

When I'm building a small ham radio, I'll frequently put a PD or PPS board inside it, with a USB-C slot on the back. These boards have a way to jumper them so they will negotiate the proper voltage from a PD/PPS supply such as a charger or battery bank. In this instance, I'd jumper it for 9V and run the cable to the same input as the barrel jack. Add a PD label to the back to require a PD power source, and there's your USB-C connection, without having to muck about hoping what you're doing will work. With most high-power chargers and such being PD and/or PPS, this is a perfectly reasonable solution for adding USB-C power to the device. The boards are available from Amazon, Ebay, AliExpress, et. al., for very low cost. The ones I use jumper with a solder bridge between two pads to select voltage and current.

What it WON'T do is any sort of DATA. It's power only.

-=-=-=-=-=-=-=-=-

73,

Gwen, NG3P

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/0f7a4455-388c-471f-8c3c-f1341444e1ben%40googlegroups.com.

[Chris Davis]

I had to google that.  I was not aware that USB-C can negotiate with the computer/charger for a higher voltage.  Very cool.

https://www.amazon.com/Dweii-Trigger-Module-Charger-Delivery/dp/B0BY8H5MS1 

[sunnybo...@gmail.com]

I decided to drive my Altair 680 kit off the USB port on my PC, which allows me to connect via TeraTerm and play.

Here's a photo of my "blue box stack". From the bottom, An RC2014 WBW (Spencer Owen kit), an RC2014 Orton 3-C (also Spencer Owen kit), the Altair-duino 680 kit (Chris Davis kit) and a Terasic de-10 Nano FPGA board with Mister MT-32 running off a Raspberry Pi-3.

No shown many other kits including the experimenter Z80 Altair-duino (was just called the Altair-duino way back when I bought it), all the PiDP kits from Oscar V. and an Imsai 8080 (duino) kit from the High Nibble.

Normally I'm firmly attached to the Z80 world as it was the first system I ever owned (TRS80 Mod1 thru 3, 4 and finally 4P which I also still have). I'm liking the 680 just because it's different.

-R

[sunnybo...@gmail.com]

I guess it would help to actually attach the photo...

[Charley Jones]

Beautiful stack! 

Sent from my iPhone 15pm!

Charley Jones, PMP

On Jan 17, 2026, at 4:13 PM, sunnybo...@gmail.com <sunnybo...@gmail.com> wrote:

I guess it would help to actually attach the photo...

To view this discussion visit https://groups.google.com/d/msgid/altair-duino/25a76dff-21e6-4d92-81d3-d37eb099acaan%40googlegroups.com.

<T1280_blue box stack 2026-01-17.jpg>

[Rob Foster]

Nice, I want one of those Orton 3C, but am burned out on kit building, I will snag one if an assembled on shows up on eBay.