I already managed to read a RFID tag with an electric toothbrush charger and an old AM radio. Basically the electric toorhbrush uses induction charging which means the charger produces an alternating magnetic field like the RFID reader would do. One day I had the idea to put a tag on the reader to see if it woule react and transmit its identifier, so I put the AM radio close to the charger and sure enough I could hear a very loud sound when putting the tag on the charger. I then connected the AM radio to my computer and recorded the signal in Audacity and I decoded the data. It was EM4100 tag.

02 is the start text (STX) control character. 03 is the end text (ETX) control character. Good that you finally remembered ASCII mode ;-)

02 is Start of text.

That relay board is a beauty. Use it for your arduino driven synchonized to music broadcast on an FM station Christmas light show.

Wonderful video and use of the oscilloscope - as someone that codes the electronics way to test always makes me rethink how I approach things.

Useful video 👍

I’ve been playing with rfid recently due to a project at work. I’ve been looking at 13.56Mhz stuff though. Using the RC522 which is available at just a pound. I think you’ve looked at that module before?

The coil is bonded by passing a high current thru it for a second or two which melts the insulation slightly while still on the winding former. It was woman's work here in the 80's ( i bet it's kids doing it now in china, the high volume stuff is at a much higher freq and gets printed.)

Good timing Julian...how do we copy these cards and duplicate it? On tags...

Just an off the wall idea. Build a RFID reader into the bottom of a bowl, place it near the door to your shop with several tags, one for each lighting scenario, hung on the wall above it. When you enter your shop, drop the appropriate tag into the bowl and hang it back up when you leave.

Your knife. In the last video you complained about the blade not snapping cleanly. On the yellow end there is a slot. Use that to break it off. Alternatively, only expose two segments and (at an angle) push the blade against something hard. Mind your eyes as it has a habit of flying off in all directions.

What is the voltage on the TX pin ? Will it work directly with an ESP32 or will I need a level shifter ?

Would like to see more of that 16 relay switching board.

Underrated meerkat noise

Jonathan I need your help please, please. I've got a 16 way mux connected to a MEGA 2560, the mux lines are for receiving serial input of tag info from multiple RDM6300 modules. I've connected a single module, powered from the MEGA 5v/GND and it reads perfectly from any of the 16 mux lines. However, when I connect a second module, the first one stops working as soon as the 5v/GND are connected. Neither module works. If I disconnect the GND from either module the other one starts working. I've tried using a power bank with the RDM6300s , common ground on power bank and MEGA but same result. I'm freaking out.

If you listen carefully at

Didn't you order some rfid tags and readers/writers a few years ago? I remember a video on it.

Do you put the small rubber cap back on the JLCPCB pen? Does it dry out?

There are also rfid reader like pn532 that can talk over i2c bus or spi and get the bonus of nfc. BTW the real deal is to have the lights controlled by voice using either Alexa or Google home with the help of HA bridge and an optional home automation controller 😁

what about edit program in that C8051F330 MCU to not only read cards and tags but also write, or reading/writing automotive chips in keys ;-)