Well, perhaps SOLVED is a little strong, maybe WIP would be better, since the North-East weather has prohibited taking the p2 airborne -- so right now, I can confirm that this works on the Ground - but haven't put it in the air - and so would suggest no one rush out and buy any of this kit until some flight tests can be completed.
I wanted to get FPV working with low latency on my iPad MINI (Retina) and/or my Nexus 7 (2013). Over the next few days I will add to the post with specific instructions on what you need and how to set it up.
Here's a photo of the various Ground Side components:
And here's a schematic for how to wire them up:
Said simply, we take the composite video output of a video receiver such as the AVL-58 and feed it to a video encoder which streams the video over Ethernet to a wireless router which in turn connects to a Hotspot provided by an iPad or a Nexus/Android tablet. On the tablet, we use a suitable app to grab a MJPEG stream from the Converter and display it. This also allows streaming to MULTIPLE clients - and with the right apps, ground side recording (albeit in low res 720x480) of image + telemetry data. If your tablet can't create a Hotspot - all is not lost. I have a solution for that use case too.
...and here's a picture of everything working:
...and finally a picture showing latency measurements. This picture shows a tiny 2 frames of latency (1/15 sec). This is understated as it shows a counter being sent to a TV and simultaneously to the Q4701/asus and onto the iPad. The TV will introduce its own latency. So this is the best possible - not the likely outcome. I have struggled to figure out a logistical setup that will let me properly measure latency from the P2/AVL58 all the way through -- but crude measurement suggests about 6 frames - or 1/5 second. Still plenty good enough.
The remaining tests are to see if the thing works in flight...but other than 24ghz interference, I can think of no reason why it would be any different - since the air-ground stuff in unchanged from a regular setup. BTW - Any video transmitter system should work - so long as you can get a composite video feed at the ground. Also, I think the 2.4ghz issue will be a non-issue since its all ground side....but that's a risk you will need to contemplate for yourself. Screen glare is another potential issue I have been working to solve and I do want to do a battery torture test at some point.
Last point. Setup of the ASUS + Q4701 and ipad/nexus is initially bloody complex. Once setup, it's easy. I will post a how-to as follow up...but couldn't wait to post, what I think is a breakthrough development.
WOOHOO!
I wanted to get FPV working with low latency on my iPad MINI (Retina) and/or my Nexus 7 (2013). Over the next few days I will add to the post with specific instructions on what you need and how to set it up.
- First the P2 related kit:
- On the P2, I have the avl-58, the iosd mini and the ground station datalink (for future use)
- On the ground side, I have the avl-58 receiver and the ground station unit.
- The A/V related kit:
- An Axis Q7401 - this takes a composite feed from the AVL-58 and converts it into an IP stream (MJPEG) that it offers via a wired Ethernet connection.
- An ASUS WL-330N 5in1 travel router. This takes the wired Ethernet input and offers it (among other functions) via a self-published Hotspot - or can also auto-bind to a Hotspot published by the iPad or Nexus etc...
- An iPad or a Nexus 7 or, in theory, any other tablet of your fancy. I have tested with the iPad and Nexus.
Here's a photo of the various Ground Side components:
And here's a schematic for how to wire them up:
Said simply, we take the composite video output of a video receiver such as the AVL-58 and feed it to a video encoder which streams the video over Ethernet to a wireless router which in turn connects to a Hotspot provided by an iPad or a Nexus/Android tablet. On the tablet, we use a suitable app to grab a MJPEG stream from the Converter and display it. This also allows streaming to MULTIPLE clients - and with the right apps, ground side recording (albeit in low res 720x480) of image + telemetry data. If your tablet can't create a Hotspot - all is not lost. I have a solution for that use case too.
...and here's a picture of everything working:
...and finally a picture showing latency measurements. This picture shows a tiny 2 frames of latency (1/15 sec). This is understated as it shows a counter being sent to a TV and simultaneously to the Q4701/asus and onto the iPad. The TV will introduce its own latency. So this is the best possible - not the likely outcome. I have struggled to figure out a logistical setup that will let me properly measure latency from the P2/AVL58 all the way through -- but crude measurement suggests about 6 frames - or 1/5 second. Still plenty good enough.
The remaining tests are to see if the thing works in flight...but other than 24ghz interference, I can think of no reason why it would be any different - since the air-ground stuff in unchanged from a regular setup. BTW - Any video transmitter system should work - so long as you can get a composite video feed at the ground. Also, I think the 2.4ghz issue will be a non-issue since its all ground side....but that's a risk you will need to contemplate for yourself. Screen glare is another potential issue I have been working to solve and I do want to do a battery torture test at some point.
Last point. Setup of the ASUS + Q4701 and ipad/nexus is initially bloody complex. Once setup, it's easy. I will post a how-to as follow up...but couldn't wait to post, what I think is a breakthrough development.
WOOHOO!
