Remote Controlled Eight-Relay Board
- An RC Firework Firing Device
Opened up and expanded
The Relay-Side: Making the Connections and Code
Wiring the Relays and Igniters
I wired the relay module according to the diagram above. Relays 1 - 7 are wired identically, whereas relay 8 is wired to provide 12v power to the igniters, when activated, and is switched to the igniters by relays 1 - 7. A white 12v LED strip is connected accross the 12v battery to show the battery is connected and provide some safety lighting. Ribbon cables and barrier terminals were convenient for this purpose.
I'm using a 12v lead-acid battery (12Ah, peak max current 75A) to supply power to the igniters. Each igniter draws 0.5A momentarily, so there's plenty to spare.
NB although relays 1-7 can be triggered, no power is provided to the igniters unless relay 8 is active and is connecting the 12v supply.
Connecting Relay Module pins to Arduino
The Arduino and relay modules are connected according to the above diagram (see code also).
Safety Features on the Relay Side
I wanted these safety features
- Safety / Task lighting
- Key Switch
- Audible alarm
- Relays Ready LED
- Safety / Task lighting => a white 12v LED strip that comes on when the 12v battery for the igniters is connected. Shows / warns igniter power is live and provides task light.
- Buzzer => sounds when arduino power is connected [arduino PIN15]. Buzzer can also be sounded as a "fire in the hole" warning by pressing character '*' on the control-side keypad.
- Key Switch => when the key is turned clockwise, the circuit is completed for the relay-trigger grounds and a red LED shows this [arduino PIN16]
Here is the relay-side Arduino code: Relay-side.
Useful peer comments on Hackaday