The Ambasat-1 is an open-source Sprite Class Satalite that you can assemble, program, and have launched into space! Your very own satellite in space! When most people hear the word satellite they think of multi-million dollar devices that are way out of the reach of your average maker. But the cost of satellites and their launch costs are decreasing at a rapid rate. This innovation is coming from companies like Planet Labs. They launch CubeSat devices, bread box size satellite, that use consumer-grade electronics to greatly reduce the cost while incurring a small risk when used in space.
You can learn more on the Ambasat website.
Kickstarter
As with many startups the project launched on Kickstarter as Ambasat-1 an Educational Space Satellite Kit with the goal of gaining funding to create the hardware and software to make these tiny satellites a reality. They also allowed for a limited number of backers to select an option to be launched into space!
Now that the Kickstarter is over you are able to buy the Kit or assembled satellites but there is currently no information on a second launch any time soon.
Technology
The Ambasat sprite satellite technology is based around an Arduino class microcontroller and uses a LoRa radio to communicate on The Things Network. A solar board is used to power the device and the payload can be a variety of small sensors to measure UV, Temperature, etc. The power and data link budgets will most likely be very thin as I suspect most of the power will go to communication and a low power firmware design will be critical.
Soldering
In hindsight, I should have paid for the assembly, but I wanted to save a few dollars and have something that would push me to learn small surface mount soldering. The other unfortunate thing is that the hand assembly documentation is seriously lacking in its current form so hopefully this guide will help others that are out there assemble their kits.
I would suggest you get a practice board and take a look at my post on how to Hot Air Reflow Solder with Solder Paste by hand linked below.
Components
The Kit comes with all the components you need to assemble the device individually wrapped from the PCB down to single cut-tape ICs and passives.
Assembly
The first thing I did was look for the schematic and the board layout files along with an image of an assembled board. This helped me orient the parts and allowed me to double-check to make sure the right value component was placed correctly. I added all three below but they can also be found on the GitHub and main website.
The kit has all the capacitors, resistors and ICs (Integrated Circuits) laid out by value and name respectively. With the PCB clamped in a Stick-Vice to keep things stable, I started adding components one by one starting with the passives that were not close to the LSM9DS1. This is because the MEMs device will be the most difficult to solder so it’s best to keep some space around it in case you need to rework it.
C4-1uf, C5-2.2uf, C1-1uf, C3-0.1uf, R2-10k, R3-1k, R4-1k, R1-1k6
Then I tackled the LSM9DS1, I spread a thin amount of solder paste on the pads just enough to lightly cover them, then used some hot air to flow the solder onto the pads. Then I used my soldering iron to remove any solder bridges so the pads were coated evenly. Then I added a bit more solder paste in an even thinner layer, I then placed the LSM9DS1 onto the pads making sure to line it up correctly I then hit it with some hot air to flow the solder again. The key to this was to get a small amount of solder onto the pads so that when you place the part and reflow the solder the part will seat correctly without bridging between critical pins. I feel like I got a bit lucky with this but thankfully they have some test code to make sure everything is working once assembled.
From there soldering the rest of the components was pretty easy in comparison.
C7-0.1uf,C6-10uf,C8-10uf,C9-0.1uf LP2985, ATMEGA328, Crystal
The LED can be a bit tricky singe it has a polarity, but the Ambasat Guide actually has a good diagram on the topic so I will refer to that.
We will wait to solder on the radio since that can be done easily without solder paste later, It’s also the most expensive part since it’s a module. So if we accidentally short something here, we don’t kill the radio as well.
We then solder on the programming pin Header parallel to the board as these will need to be removed before flight. That is why these are not soldered through the holes, but on top of them, as it would make them harder to remove later.
Now before applying power, we should check that we do not have any solder bridges, and more importantly, we have not shorted power and ground! You can do this by setting your multimeter to continuity test mode and check for beeps while testing various ground and VCC points.
Programming
The programming environment was very easy to set up due to the ingenious use of VSCode and Platformio. This allows you to easily import the example code on GitHub to get started in a few clicks.
Connect up the provided programmer to the board as shown in the picture below. Then connect the USB programmer to your computer.
I was able to quickly load up the LED Test example to make sure the basics are working and I have the diode in the correct direction.
The scary one for me was checking to see if the gyro was soldered correctly. Thankfully there is a Gyro Test example but I did need to add the workspace to get it to compile but it was a simple copy paste and change the name from LED to Gyro. Thankfully it started sending data over the serial interface!
Next Steps
Now that I have the basics set up I still need to assemble the sensor board and install the radio, from there I need to test them. The example code has been pretty helpful so far but I suspect I will need to start writing custom code to run my own experiments. But it does look like there is a comprehensive set of examples for most of the functionality and sensor payloads.
