There are plenty of multi-relay boards for Raspberry Pi, but since those are often combined with an HMI for control, SB Components decided to offer an all-in-one solution with an expansion board equipped with eight relays and a 4.3-inch touchscreen display connected to a Raspberry Pi via HDMI and USB.
PiRelay 8 specifications:
- 8x relays with 3.3V/5V trigger signal
- Input – 250V AC/7A, 30V DC/10A
- Screw terminal blocks
- NO (Normally Open) and NC (Normally Closed) modes available
- Isolation – EL357NC optocouplers with current transfer ratio (CTR) of 50-600% at IF=5mA, VCE=5V
- Display support – Optional 4.3-inch touchscreen display with 800 x 480 pixels resolution, HDMI input for video, USB for touchscreen support. It also comes with a 3.5mm audio jack, an HDMI audio output, a speaker connector, and mounting holes for the Raspberry Pi.
- 40-pin GPIO header to connect a Raspberry Pi SBC (Pi 4, Pi 3B+, Pi 3, Pi 2, or Pi Zero), or other compatible boards
- Misc – Relay status LEDs, power LED
- Power Supply – 5V DC /2A via USB or terminal block
The company says the PiRelay 8 expansion board is open-source, with an Android app to control the relays as well as Python examples. But I could not find any resources specific to the new board, only a Github repository for the earlier PiRelay-V2 from the company.
The opto-isolated relay board for Raspberry Pi has just launched on Kickstarter. Rewards start at $35 for PiRelay 8 without the display, but most people may want to pledge $104 for a pack with the relay board plus the 4.3-inch touchscreen display. They also offer complete bundles with a Raspberry Pi 4. Shipping adds 7 GBP to the UK, about 16 Euros to European countries, and $35 to the rest of the world. SB Components expect shipping to start in September 2021.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
What are the optocouplers good for? Are they seriously isolating the relay coil from the port pin? Scratchinng my head…
A schematic might reveal their design approach behind it.
Well, the ac inputs really should be isolated from the rest of the board.
And a relay does exactly what?
Am I being weird for wanting 250VAC/16A relays that max out the common household EU circuit breakers? I get these things are meant to drive small 3D printer engines and heating bodies and such so there’s no point… But still, I’d rest better knowing the relays can handle whatever I’d throw at them without me having to measure it in advance and hope nothing gets weird like when an engine cranks up drawing a bit more and such…
Regardless, I haven’t looked at the protection circuits but that specs suggest it’s a nice board with good value. Cool.