Roomba Beacon Remix

thingiverse

Roomba Beacon RemixThis is a remix of...iRobot Roomba virtual wall DIY... originally posted by saint187 on September 16, 2018https://www.thingiverse.com/thing:3104027Principal changes to this version:Replaced Arduino Pro Mini with a Nano clone.Added provisions for machine screw cover screws.Added a hole for the IR LED in the case. Also added shields on either side of the IR LED to narrow the output.Added features to the cover face for mounting the slide switch and the power LED; also added "I O" switch labeling.Added a structure to the underside of the cover for mounting components.Simplified the circuit by removing the BC547 transistor driver for the IR LED and also removed the external power jack. Made the IR LED series resistor 270 ohms.Added a 2.2 K ohm series resistor for the power LED.Added a pair of 5-pin pin header buses to simplify making connections.Changed the Arduino sketch to assign pin 3 to drive the IR LED. (Sketch .ino file is included)Assembly Notes: The 270 ohm series resistor for the IR LED yields ~ 18 mA. That's within the ratings of both the Nano output pins and the LED but could probably be a higher resistance, lower current. The Roomba avoids this like the plague; did not test with a lower LED current.Upload the sketch to the Nano before mounting.It's advisable to use a 1 mm drill in a pin vise to clear out the four screw holes for mounting the Arduino. They go all the way through the part so it may be easier to drill from the back side instead of into the posts. In my case I could see daylight through all four after printing but they were undersized.It may be necessary to trim the screw post adjacent to the Arduino VIN pin a little to provide clearance for the solder on that pin header.Heat setting probably not necessary for the threaded inserts in the case. I was able to draw them in using a longer screw. Note that the holes have a shoulder so inserts must go in from the bottom end.Dupont connectors were incorporated in the leads to the IR LED, enabling separation of the case from the rest when changing the battery.The signal on pin D3 is a 38 kHz carrier, with a continuous series of 1 mS marks and 1 mS spaces. 26 ga. solid wire was used for all except the green power LED connections; 30 ga. solid wire used for those. Solid wire was used where possible to allow wire wrapping. Battery connector and cut-off Dupont jumpers used on the IR LED leads were stranded so wire wrap could not be used for those.Cyanoacrylate gel was used for the two LEDs, to fasten the PCB strip to the Bus Support and to attach the Bus Support to the spine of the cover.BILL OF MATERIALS:3D Printed Parts:CaseCoverBus SupportPurchased or Parts Box Parts:Arduino Nano (or clone)Switch - Micro-mini slide switch, 3 Pin, 2 position, panel mount5 mm IR LED3 mm LED (green)270 ohm 1/8 Watt resistor (red, violet, brown - IR LED)2.2 K ohm 1/8 Watt resistor (red, red, red - power LED)9V Battery9V Battery snap connector2 X M2 X 10 mm round head machine screw (cover)2 X M2 flat washer (cover)2 X M2 X 4 mm brass female threaded insert (cover)4 X M1.4 X 5 mm round head self tapping screw (Arduino)2 X M2 X 6 mm round head self tapping screw (switch)3 X right-angle male pin header, (1 1-pin, 1 2-pin - D3, VIN, GND)Wire (26 ga. & 30 ga. solid)Single end Dupont jumpers, (2 pair)Solder & fluxCyanoacrylate gelPrinting:PLASupports (not for Bus Support)0.8 mm walls0.6 mm floors & ceilings12% infill0.15 mm layer height