Clean AV Buffer Module for Analog FPV Goggles + PowerPlay DVR
Click the image on the right to watch the demo video!
The FPV Signal Cleaner is a compact inline module that cleans up the composite video signal from analog FPV goggles (tested with Fat Shark goggles) before it reaches a DVR (like the ImmersionRC PowerPlay). While the internal video feed remains clean, the AV output suffers from amplified noise, distortion, and flashes, especially during RF signal fluctuations.
This module uses a THS7314 video buffer chip, low-pass filtering, and impedance matching to condition the video signal while passing audio and power through untouched. Power is taken from the PowerPlay's 7.4β8.4V barrel output and regulated to 3.3V using a buck converter to power the buffer circuit.
Everything is mounted on perfboard and housed in a small enclosure that plugs directly into the side of the PowerPlay β like a dongle.
- β Cleans and buffers composite video signal
- β Passes audio through untouched (or disconnects if not needed)
- β Regulates 3.3V from PowerPlay to run the chip
- β Dual-connector dongle design - plugs into both AV and power ports on PowerPlay
- β Compact enclosure - 3D printed case for professional appearance
- β Impedance matching - 75Ξ© resistor for proper video signal integrity
| Qty | Item | Description | Approx. Cost |
|---|---|---|---|
| 1 | THS7314D | 3-channel video buffer (SOIC-8) β Texas Instruments | $0.75 |
| 1 | SOIC-8 to DIP adapter | With header pins for breadboard/perfboard use | $2.88 |
| Qty | Item | Description | Approx. Cost |
|---|---|---|---|
| 1 | MP1584 buck converter module | Adjustable 3.3V regulator (input: 7.4β8.4V) | $2.50 |
| Qty | Value | Description | Approx. Cost |
|---|---|---|---|
| 1 | 220nF | DC blocking cap (C0G/NP0 ceramic - critical for video quality) | $0.41 |
| 3 | 75Ξ© (1%) | Output matching resistor | $0.12 |
| 1 | 470pF | Output low-pass filter cap (C0G/NP0 ceramic - critical for video quality) | $0.27 |
| 1 | 12kΞ© | Pull-down resistor(s) for noise suppression | $0.10 |
| Qty | Value | Description | Approx. Cost |
|---|---|---|---|
| 1 | 0.1Β΅F ceramic | THS7314 bypass cap (C0G/NP0 ceramic - critical for video quality) | $0.27 |
| 1 | 10Β΅F electrolytic | Bulk cap on 3.3V rail | $0.50 |
| Qty | Item | Description | Approx. Cost |
|---|---|---|---|
| 1 | TRRS 3.5mm female jack | AV in from analog FPV goggles | $0.50 |
| 1 | TRRS 3.5mm male plug | AV out to PowerPlay | $0.50 |
| 1 | 5.5x2.5mm barrel female jack | Power to goggles | $1.00 |
| 1 | 5.5x2.5mm barrel male plug | Power from PowerPlay | $0.50 |
| Qty | Item | Use | Approx. Cost |
|---|---|---|---|
| 1 | 30x70mm perfboard (cut to 30x43mm) | Mount components | $2.00 |
| 1 | 3D-printed enclosure | Enclose the module | $0.50 |
| 1 | Heat shrink / tape / glue | Wire insulation and securing parts | $3.00 |
Total Estimated Cost: ~$20-25 USD
- Sleeve: Ground
- Ring 1: Video
- Ring 2: AudR
- Tip: AudL
Note: You may only care about the sleeve (Ground) and 3rd segment (Video) and can ignore the tip and 2nd segment (audio).
Interactive circuit simulation available: Load hardware/AVCleanerDiagram-falstad.txt in Falstad Circuit Simulator
- Cut perfboard from 30x70mm to 30x43mm size
- Mount the THS7314 on the SOIC-8 to DIP adapter
- Secure female TRRS jack and barrel jack to the perfboard
- Secure the SOIC-8 adapter to the perfboard
- Secure the buck converter to perfboard and adjust to 3.3V output
- Add power filtering capacitors:
- 0.1Β΅F C0G/NP0 ceramic near THS7314 VCC pin (must be C0G/NP0 for video quality)
- 10Β΅F electrolytic on 3.3V rail
- Install video path components:
- 220nF C0G/NP0 DC blocking capacitor on video input (must be C0G/NP0 for video quality)
- 75Ξ© resistor for impedance matching (THS7314 output)
- 470pF C0G/NP0 low-pass filter capacitor from 75Ξ© (video out) to ground (must be C0G/NP0 for video quality)
- 12kΞ© pull-down resistor from video input to ground (for noise suppression)
- Connect all grounds together
- Wire the connectors according to the pinout
- Print the enclosure parts from the OnShape model DON'T FORGET THE TRRS SPACER
- Insert circuit board inside the base
- Install TRRS spacer - Screw the TRRS spacer piece onto the male TRRS jack before mounting it to the enclosure
- Screw in and solder TRRS jack and barrel connector
- Secure female barrel and TRRS with glue or mounting hardware if desired
- Slide the door in to complete the enclosure
- OnShape CAD Model: https://cad.onshape.com/documents/2e6892c1f7077560f1e7db3c/w/84a265bc11fc2bf27c14fb24/e/b1e7d4b621d2da3bc5834969
- STL Files: Available in
enclosure/PowerPlayDongle/directory
- Falstad Circuit Simulator: Load
hardware/AVCleanerDiagram-falstad.txtto view the interactive circuit - Circuit Screenshot:
hardware/FalstadScreenshot.png
Watch the full demonstration: YouTube Demo
The module uses a THS7314D 3-channel video buffer IC to:
- Buffer the incoming video signal
- Provide proper impedance matching (75Ξ©)
- Filter out high-frequency noise
- Maintain signal integrity
- Input: 7.4-8.4V from PowerPlay barrel connector
- Regulation: MP1584 buck converter to 3.3V
- Filtering: Multiple capacitors for clean power delivery
- Video Input β DC blocking cap β THS7314 buffer
- Buffer Output β 75Ξ© resistor β Video Output β 470pF low-pass filter (goes to ground)
- Audio β Passed through unchanged (or leave disconnected)
- Power β Regulated and filtered for IC operation, passed through to goggles
The 12kΞ© pull-down resistor from video input to ground serves as a critical noise suppression component:
- DC Bias Stabilization: Provides a stable reference point for the video signal
- White Flash Reduction: Significantly reduces large white flashes that occur during RF signal fluctuations
- Signal Integrity: Helps maintain proper signal levels and prevents floating inputs
- Optimal Value: 12kΞ© provides the best balance - lower values (10kΞ©) cut more noise but can cause sync/color issues
C0G/NP0 capacitors are essential for this application:
- Low Dielectric Absorption: Prevents signal distortion and ghosting
- Temperature Stability: Maintains consistent performance across temperature changes
- Video Signal Integrity: Standard ceramic capacitors (X7R, Y5V, etc.) will cause significant video quality degradation
- Must Use: 220nF, 470pF, and 0.1Β΅F capacitors must all be C0G/NP0 grade
This project is licensed under a custom license - see the LICENSE file for details. This means you can:
- β Use, modify, and distribute this project freely
- β Build and use the device for personal, educational, or commercial purposes (paid gigs, YouTube, etc.)
- β Use it in your business or for profit-generating activities
- β Cannot manufacture and sell the physical device as your own product
- β Must give appropriate credit if you share modifications
Built with β€οΈ for the FPV community
Clean signals, smooth flights!