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New Pi4b controller + power unit

Posted: Fri Dec 08, 2023 6:28 am
by SkyHiker
I recently ditched my first DIY rig consisting of a Pi4b, 12/5 DCDC and 7-port powered USB2 hub on a too-large plywood frame to a Pi4b + Pegasus power unit. That new unit looks really cool but the Pegasus is pricy. I needed it because I had to run the ASI2600 off the Pi4b's USB3 and it has a severe power limit that the Pegasus fixed. I built KStars/Ekos from source code.

I always wanted to have a second DIY rig, so I got another Pi4b, 12/5 DCDC and a 4-port powered USB3 hub. It worked out really well. The DCDC provides 15 W, which is plenty for the Pi, while I can run the ASI2600 over the powered USB3 hub. This Pi runs StellarMate, the commercial version of KStars/Ekos. I glued the 3 components together with E6000 into a nice compact unit. It looks a bit rough but it's all about functionality.

The Pi is at the bottom with the USB hub and the DCDC glued on top of it. You can see 7 available USB ports, 5xUSB3 and 2xUSB2 (one USB3 on the Pi is to connect with the USB hub).
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Here's the rear, a cut-up USB-C cable that powers the Pi with 5V to the lower left, the 12V power input cable to the right (red), and a 12V power output cable to the right (dashed), the 5V USB power to the front. The 5V port on the DCDC is to the left, the 12V port is to the right.
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Here's the bottom of the Pi that has a cut-up foam cork glued to it. This makes it easy to put it on any OTA by clamping it with a piece of rubber bicycle tube. It sits rock solid that way and is easy to move around across OTAs.
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This is a whole lot cheaper than the Pegasus that cost me $340 and equally good as far as I can tell. It worked fine when I put it on my ED80/EAF/QHY/ASI2600MC configuration.

Re: New Pi4b controller + power unit

Posted: Fri Dec 08, 2023 9:30 am
by Graeme1858
That's a good solid build Henk. I've got a Pegasus Power Box and I always thought I could build something just as good for half the price! The front end display on the pc is good though.

Graeme

Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 4:37 pm
by SkyHiker
Graeme1858 wrote: Fri Dec 08, 2023 9:30 am That's a good solid build Henk. I've got a Pegasus Power Box and I always thought I could build something just as good for half the price! The front end display on the pc is good though.
Thanks Graeme. I converted the other one too, just because it is more compact and cheaper. It fits on my Redcat51, too. I haven't used it much because the old units were too large for it. Now I have an unused Pegasus unit. I think I will keep it just in case.

Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 5:44 pm
by SkyHiker
I might as well include pictures of the 2nd unit. I recycled the 5V USB power connector because I hate to cut up a perfectly fine AC adapter just to get the connector even when I will probably never use it. I wrapped some electrical tap around it.
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Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 7:23 pm
by Graeme1858
SkyHiker wrote: Sat Dec 09, 2023 4:37 pm Now I have an unused Pegasus unit. I think I will keep it just in case.

Could you use it as a dew heater controller and monitor and to display temperature and humidity?

Graeme

Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 8:02 pm
by SkyHiker
Graeme1858 wrote: Sat Dec 09, 2023 7:23 pm
SkyHiker wrote: Sat Dec 09, 2023 4:37 pm Now I have an unused Pegasus unit. I think I will keep it just in case.
Could you use it as a dew heater controller and monitor and to display temperature and humidity?
In California dew is not much of a problem. It can be, once I was at an outreach right above the beach where it was an issue.

I haven't hooked up the dew heater that came with Pegasus. But usually, dew heaters are at the driver level. Indeed, OnStep supports it, and the Ekos driver shows the GUI for it. So, I would have to hook up the dew heater to the OnStep controller if I wanted to do it properly.

The Pegasus unit can apparently do it as is, so it's a bit of tough call if I want to make it work in OnStep. I think, usually when dew becomes a problem, it's time to pack it up. It just doesn't happen often enough to make a point of it.

Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 9:12 pm
by JayTee
Nice work Henk.

You truly are the king of the phrase "Necessity is the mother of invention."

The solutions you come up with are noteworthy.

Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 9:34 pm
by yobbo89
nice job, it does pay off to do diy, some of the components of astronomy are insanely expensive for no other reason other then niche/smaller market . it hurts my wallet buying adapters :(

Re: New Pi4b controller + power unit

Posted: Sat Dec 09, 2023 9:55 pm
by Star Dad
I have found that with a cooled camera (ie ASI294M-C) that even when there is frost on the outside of my Newtonion scope, the secondary (and so far primary) mirrors do not fog/frost up.