MountOne | DSLR Assembly.

Don't Panic!

This guide is 99% images.

Index.

If you would like to develop MountOne yourself or wish to help support my further development of the MountOne, detailed drawings, datasheets and STEP files are available by downloading the MountOne CAD Packs.

Printed Parts.

The MountOne & Astrographs were developed with Bambu Lab PLA-CF. Final testing and checks were performed with Bambu Lab PETG-CF. Parts were printed using E3D's A1 Series High Flow ObXidian 0.4mm Nozzle. I recommend PETG-CF for the MountOne and Astrographs.

Full details on how to print these parts are in the DSLR Printed Parts Documentation.

Electronics & Fixings.

The DSLR Hardware Pack includes the following required fixings.

  • GPIO Highjacker.
  • 8 x M5 20mm Screws for Plastic.
  • 4 x M2.5 Hex Standoffs.
  • 4 x M2.5 4mm Bolts.
  • 7 x M2 6mm Bolts.
  • 1 x 1/4-20 UNC Bolt.

Parts you will need to source yourself.

  • Canon DSLR & Lens.
  • Raspberry Pi 4/5.
  • 5V DC/DC Converter.
  • 7.5V DC/DC Converter.
  • Raspberry Pi 5 Active Cooler (Optional).
  • Raspberry Pi M.2 HAT (Optional).
  • Adafruit Ultimate GPS (Optional).
  • DR-E5 Battery Modules & Cable.
  • USB A to Right-Angle Mini B Cable.
  • Various Cables & Wires. 

If you have downloaded the MountOne DSLR CAD Pack, there is a full BOM inside.

The DSLR Astrograph will more than likely work fine with the Raspberry Pi 4. All the imaging is performed on the Canon camera, including storing the photos (you'll need a card in the camera).

We go through the software setup in the MountOne DSLR Software Documentation. This guide is solely for the purpose of the hardware assembly.

GPS.

Adafruit's Ultimate GPS. I have had mixed results with this GPS module, in this Astrograph and others. Feel free to try different options. 

Secure in place using two M2 6mm Bolts. I have preinstalled headers onto Tx/Rx/GND/VIN.

5V DC/DC Converter.

The hole pattern in the CAD is for a Pololu D36V50F5. However, on this occasion I have used a Waveshare DC/DC Buck Mini Module with a printed adapter. This module supplies power to  the Raspberry Pi.

Secure the module  with three M2 6mm Bolts.

7.5V DC/DC Converter.

I am using a Pololu D30V30F7 to provide 7.5V to the camera.

Secure in place with two M2 6mm Bolts.

GPIO Highjacker.

The GPIO Highjacker was developed specifically for use with the MountOne Astrographs with the aim of making the GPIO more accessible and improving the wiring. Full story on the Blog Post. 

The GPIO Highjacker breaks out power (5v & 3.3v), i2c, five UARTS and provides headers to input 5V from DC/DC converters while still allowing the use of HATs. 

Full details | GPIO Highjacker.

Raspberry Pi 4/5.

The Raspberry Pi is held in with four M2.5 18mm Hex Standoffs. I have preinstalled the RPi 5 Active Cooler.

Install the M.2 HAT. You can see how the GPIO Highjacker provides easy access to the GPIO with the HAT installed.

Secure the HAT with four M2.5 4mm Bolts.

The Wiring.

I'm not going to provide a wiring schematic as there are too many different combinations of the DC/DC converters and GPS Modules to do so effectively. Check the datasheets for each module you are using and confirm the connections and wiring aligns with the input on the GPIO Highjacker, or GPIO. It is pretty straight forward. Note that for UARTS Tx on one module connects with Rx on the other, etc.

However, there are predefined connections for the wiring harness from the MountOne and we need to conform with those. We'll be using four wires, UART Tx/Rx, +5v/GND. Refer to the MountOne Electronics documentation for additional information.

Note: The Raspberry Pi can draw more than 1.5A from the DC/DC Converter. Make sure you use higher-rated (~5A) wire for the power from the DC/DC Converter to the Raspberry Pi. Using the incorrect cable can result in low voltage warnings.

There are two channels for two cables ties on the left side, provided to constrain the camera USB and power cables.

The Camera is supplied power via a DR-E5 battery module. They are readily available online for little money. I did struggle to find the power cable though, it seems to be a non-standard size. In the end I bought a PSU & DR-E5 and just cut the wire off the PSU.

Preparing The Camera.

The printed dovetail (based off of Vixen geometry) needs to be affixed to the base of the camera using the 1/4-20 bolt.

Put the battery module into the camera, taking care with the wire.

Mount the camera.

Plug in the USB Cable.

Cover.

The Cover is held on with two M5 20mm Screws For Plastic.

Mounting the Astrograph.

Remove the cover from the astrograph. Obviously you'll need to have assembled and tested the MountOne before doing so.

Route the cables through the centre.

Six M5 20mm Screws For Plastic are used to bolt the DSLR Astrograph to the MountOne. The orientation doesn't matter, we shall position things later.

For easy access I am attaching the MountOne to a desk tripod. You can just as easily use a standard tripod, or the Printed Equatorial Tripod (PET).

I am using the Smart Hand Controller (SHC) to control the MountOne to move the astrograph to a more accessible position. There is an app available if you want to use your phone instead. The astrograph should not be connected yet. 

You'll need to connect the MountOne to 24v.

Before plugging in the astrograph, turn off the power.

Check the wiring again. Confirm everything is as it should be.

If all is well. plug the power back in again.

There should be no magic smoke.

Check everything is working, the Raspberry Pi should power on, along with the DSLR.

After confirming everything is working, turn off the power (safely shutdown the RPi first), and fit the covers. Next, we will go through the Software.

Glamour Shots.

Continue to the DSLR Software Documentation.

Back to Main Documentation.