DIY Video Diversity with Arduino - Please Review!
I've been wanting to get a diversity for a while now, but ,as I've been finding with this hobby, I wanted to build something rather than buying a prebuilt unit. This led me to IBCrazy's diversity. I had problems sourcing the video switching chip (MAX4547CPE) and didn't want to go the relay route. That combined with the fact that I've also wanted to buy an Arduino for a while now "forced" me to try design a diversity system with it.
So enough with the excuses as to why. Here is my design. As I am no electrical expert, it took a bit of research to try figure out how to go about this. I have made mistakes. Please find them (or offer improvements) before I go buy everything!
The circuit diagram is below. It is my first time actually using Fritzing, as well as making a circuit diagram, so please excuse if I haven't done things correctly. It is probably a little confusing.
The parts (as per circuit diagram):
IC1,2,3 (Video Multiplexers) - LT1203CN8#PBF http://www.digikey.ca/product-search...03CN8%23PBF-ND
IC4,5,6 (-5V generators) - MAX232IN http://www.digikey.ca/product-detail...40-5-ND/371562
IC7 (Amp for dual outputs) - MAX457CPA+ http://www.digikey.ca/product-search...AX457CPA%2B-ND
5V Regulator (+5V generator) - MIC29300-5.0WT http://www.digikey.ca/product-search...ds=576-1121-ND
Arduino (the brains) - Arduino Uno R3 http://www.solarbotics.com/product/50450/
LCD (yes, this one's over the top) - Adafruit RGB Backlight http://www.solarbotics.com/product/18984/
Piezo Buzzer - [Unknown Part #] http://www.solarbotics.com/product/17855/
Push Switches (on Tx for interaction) - 40-3979-00 http://www.digikey.ca/product-search...Words=515PB-ND
Various Resistors and Caps - I have some lying around that I can use
Various Connectors - Also have lying around
I have not designed the code within the Arduino yet, but it should cycle through the the RSSI values (voltages, mine being 0-5V inversely scaled) and output to the multiplexers to select the best channel. The LCD would be for whatever outputs I want (probably lipo voltage and RSSI values), two switches for manual video selection etc, and speaker for warnings and interaction (when switching channels with buttons etc).
So I have some questions:
1. Is the current supplied by the MAX232s large enough for the video ICs? I had trouble finding a source of -5V.
2. Are the resistor values correct for the video amp? I took what looked to be right off of the datasheet.
3. Do I need to place capacitors across any other rails? I found online that the one for the 5V regulator is important.
4. Is there anything wrong with the diagram / improvements / do you think it would work?
Let me know if the .zip isn't working. I use WinRAR (.rar). Attachments wanted a .zip...
Lastly, I realize that this may cost me a lot more time and money than say a micro diversity, but I enjoy the challenge.
Thanks for reading and reviewing!
I will try to look at this more carefully later and give you some more feedback, I also built a diversity switch based on arduino (4 RX's rated by RSSI only) but I switched to circular antennas and don't bother with any diversity at all anymore...
Check out my old post
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