Proektor & ByteBoss
Hey Proektor, I’ve been chewing on the idea of writing a lightweight automation script to control your projector’s power, focus, and lens shift over the network. Got any thoughts on the best protocol to hook into, or tricks to keep the latency under 200ms?
Sure thing! For a lightweight, low‑latency script I’d start with the projector’s native VCP/DDC‑CI interface. Most modern units expose that over the video cable and, with a little adapter, you can talk to it over IP (there are RS‑232‑to‑Ethernet converters that do this).
If you want to avoid the video port altogether, look for a vendor‑specific web API—Epson’s eControl, Sony’s SPT, or the Epson RC‑API. Those usually listen on a TCP port and accept short, single‑packet commands. The key is to keep the payload tiny (just the command byte) and to use a persistent TCP socket so you don’t pay the connection‑setup penalty each time.
For latency under 200 ms, stick to UDP if you can (most projector APIs don’t need reliable ordering), or use plain TCP with a very small read buffer. Run the script on a machine that’s wired to the projector’s network, keep the loop unblocked (asyncio or threading), and avoid any heavy serialization. A simple “Power ON” packet sent every 10 ms will keep the device happy and the round‑trip time well under 50 ms in a local LAN.
Bottom line: use the built‑in VCP over a local IP bridge, keep packets short, stay on a wired link, and don’t block your event loop. That’s the recipe for smooth, sub‑200 ms control. Happy scripting!
Sounds solid. Next, pin down which VCP commands map to focus and lens shift for your model, then build a tiny async loop that listens for a local socket or a simple UI button. Keep the socket open, send the command byte, and read the ACK in a non‑blocking way. That should give you the tight control loop you need. Need help mapping those VCP codes?
Sure thing! For most Epson‑style projectors the VCP map looks like this (check the exact manual for your unit just in case):
- **Power** – 0x41 (on), 0x42 (off)
- **Focus** – 0x44 (single‑step focus)
- **Auto‑Focus** – 0x48
- **Lens Shift X** – 0xE0 (positive moves right, negative moves left)
- **Lens Shift Y** – 0xE1 (positive moves up, negative moves down)
So your async loop can open a TCP socket to the projector’s DDC‑CI bridge, keep it open, and send a tiny packet like `[0x44]` for focus or `[0xE0, +3]` to shift right three steps.
Read the ACK byte in a non‑blocking way (select/epoll or asyncio’s streams) and you’ll stay well under 200 ms. That’s the tight‑control recipe—let me know if you hit any snags!
Nice, that covers the essentials. Just make sure the bridge keeps the connection alive; some adapters drop the link after a few packets. Also watch out for the ACK format—if the projector sends a 0x55/0xAA handshake, you’ll need to parse that. Anything else you want to tweak?