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INDI Library v1.9.8 Released (29 Sep 2022)

Bi-monthly INDI Library released with new drivers and bug fixes.

Astrohat - An open hardware RPi Hat for astronomy equipment

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If the goal is to power everything through this, I'd worry about the current draw of a mount while slewing. I'm pretty sure I've seen my Atlas Pro draw 4 or 5A, but just for a short while.

USB outputs might be nice, but I suppose one could just connect a powered USB hub to this hat.
AP1100 & Orion Atlas Pro, WO/ZS105 w/Moonlight V2 focus, GSO RC10 w/RSF focus
ZWO ASI1600, Astronomik Filters, ST80, QHY 5L-IIm.
KStars/Ekos/Indi on NUC10 & RPi4 w/SSD -- Ubuntu
Projects: Greedy Scheduler, Terrain, Polar Align, Analyze, Linear Focuser, SEP MultiStar & GPG Guide, FITS autostretch.
3 years 6 days ago #46343

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That sounds a lot, my EQ6 fully loaded barely passes 2A while slewing. In any case 6A per channel should be OK as long as the neighboring channel (with which they share the load) is on less than 0.5A (they share 6.5A rating)

I plan to do some extensive testing on the loads to confirm the design assumptions.

There is no way to get USBs through the GPIO header of the RPi, so that leaves you with the option to sacrifice one rpi port and put a hub. It makes little sense to integrate functionality in this hat unless it can be supplied through the internal GPIO header.
3 years 6 days ago #46344

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Since we are going for an aluminum case, the antenna needs to be external. It also allows for flexibility of placement for the whole system. Having an external thing though got me thinking.... why not get the GPS completely external (IC + Antenna) and thus save on internal space (since we are already packed) and also allow for a possible usage of the TTL (serial TX/RX, VCC, GND) port for something else (in case someone does not want the GPS). Such GPS modules are cheap and look like this . Makes sense?
3 years 6 days ago #46345

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I pushed some changes on the repo and concatenated a bit the BOM in order to do some price calculations. Here is what we are looking at:

All the components I selected are high-grade ones. Automotive and Industrial grade capable of performing to extended temperature ranges (since it is highly important imho for our setups) and less prone to EMI. I did not "cut-corners" at any point during the design and component selection process. All in all if someone was to buy today all components for the board you would be looking at around 45 USD. PCB production would be around 5-10 USD depending on your source. (w/o shipping obviously).

Now those are prices for a *single* board, and without trying to make everything less expensive (e.g. searching for cheaper connectors, cheaper RTC, replacing some Caps with cheaper options etc).

Just to get an idea about how prices differ on 100x scale, if you were to produce 100 boards like this you would be at around 35 USD including assembly! (with a possibility to get a bit lower while still keeping quality). (still w/o shipping ;) )
Last edit: 3 years 6 days ago by Pierros Papadeas.
3 years 6 days ago #46347

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Well as far as I am concerned that is an absolute bargain, and I would pay double for it...mind you I am in the UK so I have all the import duties and taxes too.... :)
Stellarmate OS on Raspberry pi4b
Skywatcher EQ8 pro, on steel pier
Takahashi FSQ85, FS60cb & Meade 8” SCT (de-forked)
Starlight Xpress SXVR H18, SXVR M25c, Lodestar x2 Guide Camera
Pegasus Ultimate Hub V2 for all USB & Power
Pegasus focus motors on all scopes
3 years 6 days ago #46350

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This cooler is definitely cutting it! Keeps my Pi4 at 45 C and below!

smile.amazon.com/gp/product/B07V7SS5BZ/r..._title?ie=UTF8&psc=1

Highly recommend, as long as you can 3D print your own case for it.



BTW, I would be happy to share the FreeCAD and STL files, if anyone wants them (and hopefully improve on them). They are not very elegant, but functional for my purposes.
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
Last edit: 3 years 6 days ago by Jose Corazon.
3 years 6 days ago #46351
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Anyone able to guess if the hat alone would fit onto a Odroid-N2 without modification?

www.hardkernel.com/blog-2/odroid-n2/http...om/blog-2/odroid-n2/
120 MM Skywatcher Esprit + Celestron CGX, ZWO ASI 224MC guiding, Pegasus FocusCube+PPBA
Nikon Z7 8256 x 5504 4.34 um. Triad Ultra Quad NB Filter
1) MeLE Quieter3C 8G Ubuntu-mate 22.04.1 2) Odroid-N2. 3) StellarMate RPI4 8G
The good, the bad, the ugly at sciencedowneast.no-ip.ca/zenphoto/
Last edit: 3 years 6 days ago by Jerry Black.
3 years 6 days ago #46352

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All well and good but would not work on what this thread is about...... :)
Stellarmate OS on Raspberry pi4b
Skywatcher EQ8 pro, on steel pier
Takahashi FSQ85, FS60cb & Meade 8” SCT (de-forked)
Starlight Xpress SXVR H18, SXVR M25c, Lodestar x2 Guide Camera
Pegasus Ultimate Hub V2 for all USB & Power
Pegasus focus motors on all scopes
3 years 6 days ago #46354

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"All well and good but would not work on what this thread is about"


I'm not so sure, it just might be possible. That's why I showed the image with my current cooling solution.

I agree that with the conventional HAT design, which sits directly on top of the Pi board this would not work. That would fatally interfere with the cooling, whichever way you try to cut it.

However, this tower is hands down THE BEST cooling solution for the Pi4 (check out Christopher Barnatt's video on this cooler and how it compares to other solutions:
)

So I thought it might be worth exploring at this early stage, whether the AstroHAT can be designed in a way that allows incorporating this top of the line cooler for the RPi4 into the assembly.

I just think that might be possible, all that is required is to add some GPIO connection extension adapters that allow it to be moved up above the cooler. The 3D designs can easily be modified to make a case that incorporates the HAT with the cooler sandwiched in between the HAT and the Pi4 board and forming essentially a wind tunnel the cooling air is being sucked through, thus cooling the Pi4 and the HAT at the same time.

Worst case scenario, one can just use a cable to connect the HAT to the PI4 board ( core-electronics.com.au/raspberry-pi-b-g...-cable-40-pin-6.html ), but having a solid GPIO extender of the correct length would be preferable. That must exists somewhere.

It may be sufficient to stack 2 of these connectors on top of each other to clear the tower: cnclablb.com/raspberry-pi-gpio-tall-header-2x20.html

I would LOVE to have that construction on my rig. At the moment, I have 3 power lines running up the rig, one for the 12V needed to run the mount and the dew strips, one to power the USB hub and one to power the RPi4. If I could replace that with a single power line running to the HAT/RPi4 and everything else being powered off that, that would be ideal.
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
Last edit: 3 years 6 days ago by Jose Corazon.
3 years 6 days ago #46355

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Adding to my last post, Pierros, if you think that would be feasible, then I would suggest including a ground and a +5V pin on the BOTTOM of the board, to allow for the direct connection of the tower cooling fan (without having to run the wires around the HAT board and connect them to the pins on top).
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
3 years 6 days ago #46356

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Active cooling is probably not required.
The RPI foundation have recently released a new firmware for RPI4 with better thermal management.
There are passive cooled cases which rival active cooling now available.
Ambient temperature outside at night works to reduce heating.
Finally, active cooling adds bulk and complexity.

I'd like to add a vote for focus motor driver be added
locking or latched DC connectors would be icing on the cake
Last edit: 3 years 6 days ago by Rob.
3 years 6 days ago #46360

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Maybe not required, but for most of the time that Pi4 runs at 30 degrees C at RT. That can only be good. It crashes far less than my also actively cooled Pi4, but that one only has a fan blowing down on the heatsink. That goes up to 70 degrees C, which is when it is being throttled. I suspect that's one reason why it crashes more often.

No matter, with the design Pierros has posted so far, I can make this work with my large active cooling fan.

Really looking forward to implementing this!

Best

Jo
Atlas Pro AZ-EQ, ASI1600MM-Pro, ASI120MM-S, ES102ED, WO-Z61, Nikon D3300, ASI-EFW, ZWO LRGB,Ha,O3,S2 filter set
3 years 5 days ago #46366

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