Wireless DMX Transciever
A wireless transceiver operating on 2.4GHz for transmitting and receiving DMX signals from a controller
I created this product on request from a friend expressing reluctance on buying very expensive DMX transceivers. I have designed an inexpensive product that can perform wireless transmission of data for controlling lighting, fog machines, or any other DMX compatible devices.
Initial Thoughts
I first considered what Integrated Circuit would be the most efficient chip to center my device around.
I researched DMX512 and found some relevant data:
DMX is an asynchronous data transmission standard, so max clock speed of my IC will not be relevant, at least in terms of DMX.
​
My device will also need wireless transciever capabilities, and will also neef to be complete in a timely manner. Thus, to make designing and modifying my device easy, I decided to go with a microcontroller as my IC.
​
After performing more research on microcontroller DMX emulation, I came across the DMX emulation library, DMXSerial, which is for the ATmega and ATTiny ICs. Thus, I opted to use an IC from one of those families.
​
To make my device small, I considered using a IC from the ATTiny family, however I immediatly encountered issues with the DMXSerial library, so I researched the DMX transmission standard a bit more to see if I could create my own library of code in AVR Assembly.
I used information from this site to make some basic ASM code. Due to my limited knowledge of ASM, it was ultimately very unstable, as the signal timings were off by quite a large margin.
To preserve time, I opted to use the Arduino line of ATmega ICs, the specifics of which I will cover in the next section.
Constraints
Time:
- Due to demands of my friend, time until the completion of the device must be kept to a minimum. As such, I will be using a microcontroller to eliminate designing complex circuitry.
Size:
- The device size should be kept to a minimum. I selected to use the smallest of the Arduino microcontrollers: the Nano and the Pro Mini
Expenses:
- The main objective of this project is to keep expenses low. The MAX485 IC and other supporting passive components are of marginal cost, so the main factors are the cost of manufacting a PCB and the microcontroller. I found that the cheapest site (And my personal go-to) for creating PCBs is JLCPCB. The Arduino Nano and Pro Mini are of similar price so the easiest one to implement based on other design constraints will be chosen.
Power:
- A cheap power source is vital for this device, as indicated by my friend. Batteries are out of the question, as they are far too expensive and would need to be constantly be recharged. I opted to go with a simple USB power supply, similar to a phone charger. To further simplify power and programming capabilities, I chose to go with the Arduino Nano, as it has a built-in USB Mini connector.
Capabilities
The following is a list of functions that are desired by my friend to be in the design.
Power Indicator Light (Red)
Transmission Light (Green)
Receiving Light (Blue)
Wireless Transmission (~50m)
- This is accomplished through the NRF24 low power breakout board. Sufficient range is desired, so the long range model is chosen.
Receiving/Transmitting Switch
- Used to change modes between transmitting DMX to receiving DMX
Programming Jumper
- Used to manually disconnect the RX pin of the Arduino Nano so that programming can be changed
Parts
- LEDs
- Arduino Nano
- XLR Connector (Female)
- DPSTÂ Switch
- 2N2222 Transistors
- 100 uF Capacitor (Ceramic or Electrolytic will do)
- NRF24 Module
- MAX3468
- REG1117 3.3V Voltage Regulator
- Resistors (See circuit for values)