Roshamglo Project: TV-B-Gone

Contributors: Shawn Hymel
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Hardware Assembly (Optional)

In its default state, the Roshamglo badge has an IR transmission range of about 5 feet. This was done by design to prevent people from bouncing signals off other people and interrupting Rock-Paper-Scissors games.

However, 5 feet is a little short for being able to control a TV from across the room. You don't need to upgrade the hardware, but if you do, you can easily shoot TV beams from 40+ feet away.

First, choose a resistor value you want to use to upgrade your badge's range. Something between 47Ω (40+ feet range) and 1kΩ (around 10 feet) will work the best. Note that the resistor will be in parallel with the 1.5kΩ resistor that's already on the board. To help you decide what to choose, here are some common resistor values that should work:

ResistorCurrent Through LEDPredicted Range
47Ω37mA40 feet
100Ω18mA20 feet
220Ω9mA12 feet
330Ω6mA10 feet
470Ω5mA8 feet
1kΩ3mA6 feet
Open1mA5 feet
Note: If you want the maximum range, just use a 47Ω resistor. You could get away with a smaller resistor, and therefore more current, but keep in mind the IR LED is rated for a maximum of 70mA. Things could get hot.

In the corner of the Roshamglo board, by the USB connector, you will see two holes situated diagonally toward the center of the board with the label R_Ext.

Resistor holes on Roshamglo

Solder your chosen resistor into those holes. We recommend bending the resistor's leads so that the resistor folds nicely onto the board and does not touch other components.

Extra resistor added to Roshamglo

Resistor bent between components