Scrolling LED signs were pretty keen back in the day, and now they’re pretty easy to come by on the cheap. Getting a signboard configured for IoT duty can be tricky, but as [kripthor] shows us, it’s not that bad as long as security isn’t your top concern and you can tweak a serial interface.
[kripthor] chanced upon an Amplus AM03127 signboard that hails from the days when tri-color LEDs were the big thing. The unit came with a defunct remote thanks to leaking batteries, but a built-in serial interface offered a way to connect. Unfortunately, the RS-232 standard on the signboard wants both positive and negative voltages with respect to ground to represent the 1s and 0s, and that wouldn’t work with the ESP8266 [kripthor] was targeting. The ubiquitous MAX-232 transceiver was enlisted to convert logic levels to RS-232 signals and a small buck converter was added to power the ESP. A little scripting and the signboard is online and ready for use and abuse by the interwebz — [kripthor] says he’ll regret this, but we’re pleased with the way the first remote access turned out. Feel free to check out the live video feed and see what the current message is.
Personally, we don’t have much use for a signboard, but getting RS-232 devices working in the Arduino ecosystem is definitely a trick we’ll keep in mind. If asynchronous serial protocols aren’t your strong suit, you might want to check out this guide to what can go wrong by our own [Elliot Williams].