Differences
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iothings:proiecte:2022:razvanandreistoica [2023/01/20 02:51] razvan.stoica0211 |
iothings:proiecte:2022:razvanandreistoica [2023/01/20 03:01] (current) razvan.stoica0211 [2. Hardware] |
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| ===== 2. Hardware ===== | ===== 2. Hardware ===== | ||
| === Mechanical Elements === | === Mechanical Elements === | ||
| - | * The largest part of the project is the chassis. This allows the movement of an antenna on two axis and also hosts all the electronics. | + | * The largest part of the project is the chassis. This allows the movement of an antenna on two axis and also hosts all the electronics. It uses 4 radial bearings and one axial bearing. Everything (except for the bearings, axes and screws) was 3D printed with PETG. |
| {{:iothings:proiecte:2022:fusion_-_copy.png?300|}} | {{:iothings:proiecte:2022:fusion_-_copy.png?300|}} | ||
| * The antenna is one of the most important parts of this project. I chose to go with the default antenna that came with the RTL-SDR Kit. It is a V-Dipole adjustable one. In order to make this project work, I had to adapt it and print a piece that keep the two poles at a 120 degree angle. According to an article from the RTL-SDR forum, each pole's size must be 53.4cm. | * The antenna is one of the most important parts of this project. I chose to go with the default antenna that came with the RTL-SDR Kit. It is a V-Dipole adjustable one. In order to make this project work, I had to adapt it and print a piece that keep the two poles at a 120 degree angle. According to an article from the RTL-SDR forum, each pole's size must be 53.4cm. | ||
| {{:iothings:proiecte:2022:adams_v-dipole-500x375.png?300|}} | {{:iothings:proiecte:2022:adams_v-dipole-500x375.png?300|}} | ||
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| + | * A dedicated ground plane had to be built for the GPS antenna. It is a 70x70mm PCB with a hole where the cable of the antenna passes. | ||
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| - Go to File -> Record -> Auto Record | - Go to File -> Record -> Auto Record | ||
| - Wait & Hope | - Wait & Hope | ||
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| + | But how does it work? | ||
| + | * The SDR#, is, as the name says, a Software Defined Radio. It is used to receive and filter radio waves. This tool uses RTL_TCP as a device (the RTL_SDR connected to the RPi. | ||
| + | * GPredict is a software that tracks satellites and predicts their future positions. This tool will adjust the frequency to the desired satellite (closest one when auto-tracking). | ||
| + | * WXtoImg takes the analogic data and converts it into images. This software receives the data from SDR# via a virtual "audio cable". | ||
| ===== 5. Challenges ===== | ===== 5. Challenges ===== | ||
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| * The device has 3 antennas near 2 big motors, what could go wrong | * The device has 3 antennas near 2 big motors, what could go wrong | ||
| * RTL-SDR is getting hot, please don't burn | * RTL-SDR is getting hot, please don't burn | ||
| - | * GPS doesn't work indoors (only near windows) | + | * GPS doesn't work indoors (mostly works near windows) |
| + | * The main antenna is not optimal | ||
| + | * The IMU loses its calibration quickly, doesn't have an EPROM and is very hard to calibrate | ||
| + | * The IMU doesn't even reach 90 degrees when vertical, for some reason | ||
| ===== 6. References and Links ===== | ===== 6. References and Links ===== | ||
