Mr.RC-Cam

HeadPlay HD Goggle Upgrade: Add 5.8GHz Diversity & DVR

44 posts in this topic

Again, I understand that I have an off brand Chinese diversity module, and you may not have answers for me.  I have my China Diversity module connected without your buffer at the moment.  It wold turn on then shut down to just a series of Chinese letters.  Well I switched from my 3 cell to a two cell and now it works fine.  On the three cell is shuts back down. The voltage going to the diversity module is 4.2v on the two cell (maybe needs a charge) and 4.85 on the three cell.  The module says it wants 3.5v to 5.5v.  At any rate, I bought the low voltage 5v buzzer as well and the module has the circle where it goes, but what is the point of a 5v low voltage buzzer on a device that is regulated to less than 5v anyway?  I am a bit lost.  My brain says perhaps I have a module that wants about 4.5v an I need a variable voltage regulator but not sure what the point of the buzzer will be in that case. 

Edited by Kingdon Humann

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The first time I powered mine the OLED showed English text and the menu nav switch worked.

Edit: There is something wrong with your board if it does not accept 5.0V. But regardless, the typical "5V" Mag buzzer will work on less than 5V, some buzzers will continue to work as low as 3V with a slight reduction in volume. Furthermore, the buzzer is optional, so don't worry if you decide to not install it.

 

Edited by Mr.RC-Cam

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Thanks.  It gives me a data point though Im not sure what to make of it.

Edited by Kingdon Humann

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Thanks again.  Sounds good, though I agree something seems amiss.  Time to sleep.

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Sounds good, though I agree something seems amiss.

The thing about the Chinese FPV board cloners is that they rarely know what they are doing. On top of that, the eBay sellers are clueless too. It's double jeopardy on our end due to poorly designed copies and error prone published specs.

I looked at the photos shown in your eBay link. Assuming that you received what is shown there, I highly doubt their claim that it was designed to run on 3.5-5.5V. Evidence suggest that it has a onboard 5V VReg that expects 2S-3S. See my comments in the images taken from the eBay ad:

dc-pwr1.jpgVreg-5V.jpg

There's also a design error on the VReg. The VReg IC's input leg has a 1K resistor on it that appears to connect the 2S-3S power input to ground (not sure why they did that). There should be a small value cap (0.1uF is typical) directly on the VReg's power-in leg to ground to ensure VReg stability.

FWIW, because they used a linear VReg be mindful of excessive heat / thermal shutdown if you power it with a 3S. If it gets blazing hot on 3S you might be better off with using 2S instead.

 

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wow!  Thanks so for all the info.  You totally went out of your way.  I found that on the edge of our Headplay board there is a 12v a 5v and a 3.3v solder pad.  I connected the Chinese diversity up to the 5v and a ground and took my own voltage regulator out of the circuit.   It seems to work fine now, on my bench at least.  Goes through all its menus and displays which receiver A or B is getting the best channel.  It does seem to have trouble finding my channel.  Often stops on some random channel or right near my channel..  At least it reads it out and allows me to adjust manually.  I like this thing. I can run my clover leaf and my helical antenna at same time.  Raining some more for the next few days but for now it seems functional.  I will try to hunt down the voltage reg on the Headplay board so I can make sure that isn't heating up.  All in all a great idea by you.  Thanks for your trouble shooting ideas.  I think my problem was putting my v regulator on the 12v solder pad next to the video pad.  The cheap reg I have heated up the Headplay board until it finally melted a trace this morning on 3s.  Fortunately I was able to repair it and all is working well now.  

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I found that on the edge of our Headplay board there is a 12v a 5v and a 3.3v solder pad.  I connected the Chinese diversity up to the 5v and a ground and took my own voltage regulator out of the circuit.

Just my opinion, but I'd recommend using the built-in VReg or another dedicated VReg to power your extra stuff. This will reduce the burden on the Headplay VRegs.

EDIT: BTW, if you are connecting external power to the 2S-3S input then keep in mind that applied voltage needs to be at least 6V for the internal 5V VReg to work correctly.

 

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It does seem to have trouble finding my channel.  Often stops on some random channel or right near my channel..  At least it reads it out and allows me to adjust manually.

This is not unusual; The Autoscan feature on many FPV receivers is subject to this issue. Convenient in principal, when autoscan is used it can be fooled by your nearby 5.8GHz vTx's strong RF signal and cause an adjacent Rx channel frequency to be chosen instead of the exact match. The big surprise occurs later -- The video image will look fine until your model is 25-100 meters away. Then the mismatched channels will drop the video link like a rock and you'll be flying blind. Avoid this by setting it manually to the correct frequency that matches the vTx.

 

Edited by Mr.RC-Cam

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Signed up just to say THANK YOU for all the work you put into both the project and the writeup.  Bookmarked for future project!

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If I (electronically muddled) can get this to work, so can anyone else who is willing to ask a few questions along the way.  I now have my clover leaf antenna and a helical antenna working simultaneously, plus I can see what channel I am set to on the readout.  This rocks!!!

Edited by Kingdon Humann

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Thanks for the feedback!

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Great project, I loved building this! Everything fits together very well and the instructions are good.

Just a few remarks and questions:

- Your pictures show all ground wires from the DVR to the buffer board, I did only connect a single lead to save some space

- Your schematic does not show +5V/GND connections of the DVR

- The top screw was a little short I think, could use 16mm

- My RX5808 pinout showed the OLED Port in the middle and +5V/GND on the side, but I wired it up as you suggested as both pins (VCC and +5V) deliver 5V

- How did you calibrate the diversity board? I read the instructions saying the board will measure max and min RSSI and ideally I should remove the antenna, how is this supposed to measure max RSSI without antenna?

- I have a lot of noise but improved range (compared to the builtin rx), any clue where the noise could come from?

Again, great project and many thanks for taking the time to document it for us.

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Thanks for the feedback!

When you calibrate the RX5808 it is recommended to remove both vRx antennas (Do NOT remove vTx antenna). This prevents over-saturated RSSI levels because the vTx is nearby. My method is similar, but less convenient. I do it outdoors (in a wide open area) and leave all the antennas on. The vTx is moved about 50 feet away, then the RSSI is calibrated.

Faint horizontal/diagonal lines in the image is "normal" for modded HeadPlay Goggles (affects some installations, not all). It's due to its noisy DC-DC power supply. If this is the issue you have then filtering the RX5808 Pro's 12VDC power from the HeadPlays might help. Here is a video that shows the noise so you can confirm you have the same issue:

However, if the noise you are seeing does not match the YouTube example then the problem is caused by something else. The most common mistake is using an adjacent RF frequency on the RX5808 Pro rather than using the exact frequency that matches the vTx. This results in a "working" video image that has excess noise.

 

 

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On 5/18/2017 at 6:05 PM, Mr.RC-Cam said:

However, if the noise you are seeing does not match the YouTube example then the problem is caused by something else. The most common mistake is using an adjacent RF frequency on the RX5808 Pro rather than using the exact frequency that matches the vTx. This results in a "working" video image that has excess noise.

No, unfortunately its not a little noisy like in the video you linked, its really bad. I checked today with different channels and antennas and found out that one of the receivers seems to have problems. If I move one antenna from one side to the other, the pictures fine on the left rx but totally distorted (even when only meters away) on the right one. Think I will need to return the rx to banggood...

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This is a great build. Thanks for putting it all together. I have everything but the 4 pin connectors between the Headplay board and the buffer board. What did you use there? I've done some searching today but came up with nothing. 

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I used a 4-pin micro JST 1.25mm connector. eBay has them.

 

 

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On 10/29/2016 at 3:56 PM, Mr.RC-Cam said:

The THS7413 IC is only available in a SOIC8 SMD package. I used a SMD to 8-pin DIP adapter board for easier mounting on the perfboard.

I cannot identify the input pin 1 on my Video Amp IC, even after looking at the spec sheet. Is it the bottom left with the text facing? There is not dot.

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Bottom left would be my guess too. FWIW, an authentic THS7413 will have the Pin-1 index mark as shown on the data sheet.

Sounds like you received a unauthorized (fake) part. If it doesn't work then be prepared to purchase another one from a trusted mainstream supplier (e.g. Digi-Key).

 

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Aw man! I thought Mouser was good. Well, I did buy two chips and four converter boards. Thanks!

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