Replaceable parts

Please contact David Brown, david_h_brown@uri.edu if you need replacement parts not listed here. 

Tariff alert (August 2025): With Trump's ending of the "de minimis" tariff exemption for packages valued under $800, be careful where you order. The combination of tariff and additional fees that may be levied by the shipper (UPS, FedEx, DHL) can dramatically increase your cost. 

Laser module

The laser module used in the URI Laser Scarecrow from 2018 through 2024 is the "22*70 Fat Beam 532nm 50mW Green Dot Laser Module for KTV Bar DJ Stage Lighting" from Besram Technology d.b.a. Laserland. We have made small modifications to the stock part (see photos below).

https://www.laserlands.net/diode-laser-module/532nm-dpss-green-laser-module/fat-beam-532nm-green-50mw-laser-diode-module-f-ktv-bar-dj-stage-lighting.html 

PRODUCT CHANGE: that link now (July 2026) goes to a module that is 25mm diameter and probably shorter. That doesn't seem like it will fit. The module used to be 22mm diameter by 70mm long. It's possible they've just added the 5V and 12V variations. I'm checking on that with them...

(August '25) Laserland also sells through eBay and include the tariff in a nominal shipping cost (from China). (You have to pay the shipper separately if you order from their website). Try searching for "laserland fat beam green laser 50mW 22x70" and see what turns up that looks.

Caution: Laserland seems to "improve" this module over time. We have noticed that the focus is better and power much increased relative to the first few years. In 2024, we measured power more typically around 75-80mW and occasionally just past 100mW. If you replace the module, please see the latest URI laser scarecrow operating manual for calculation of the nominal optical hazard distance (NOHD).

Note: In models prior to 2024 we replaced the provided connector with one designed to plug in to another wire instead of a board. The pins size and spacing of the provided connector is physically compatible with the one we used, so while it will be a bit of a challenge to tuck the extra wire out of the way, you can force the provided connector into the plug coming from the slip ring.

Servo

The Futaba s3107 micro servo motor (https://futabausa.com/product/s3107/) tilts the laser module up and down. Unfortunately, Futaba USA has been out-of-stock for more than a year (June '26) and didn't respond to my inquiry about whether it's still a current product. At least one of their distributors says it's discontinued, but you might still find some old stock online. 

Microcontroller

For 2022 through 2024 models, sources for the Espressif ESP32-DevKitC-VIE are listed at the end of the firmware update page which you'll need to program it: https://davidhbrown.github.io/laserscarecrow-firmware/ 

For the 2018 and 2020 models, Sparkfun's Arduino Pro Micro (5V version) was used for initial development, but less-expensive clones (here's one that may still be available) were used in production. You will need the Arduino develop environment (https://www.arduino.cc/en/software) to program these using the firmware program downloadable from https://github.com/davidhbrown-uri/laser-scarecrow-arduino. 

Stepper driver

The stepper motor rotates the arm with the laser. The stepper driver takes signals from the microcontroller and 12V power to control the stepper motor. If you need to replace the stepper driver, be sure to configure it to deliver 0.67A.  Review the manufacturer's instructions or contact us for help with that. You'll need a multimeter and a tiny flat-blade screwdriver.

Cables

12VDC Power input: 2024 model uses 20AWG 2-conductors "UL2464" outdoor-rated cable such as https://www.amazon.com/URCIANOW-100FT-Conductor-Electrical-UL2464/dp/B0CGX9LV63. Only two conductors are needed; if you happen to have some with more, that's fine so long as it is 24AWG or thicker (AWG 22, 20, etc) and fits the PG7 cable gland.  2023 and earlier used low voltage landscape lighting wire (16/2). Be sure if replacing the piece that goes through a cable gland that you fill the center channel between the wires which otherwise will leak. We used adhesive-filled heat-shrink tubing. Rubber tape might also work.

Controls to bucket: 2023 and 2024 use a standard 15' outdoor-rated Cat5 network cable. Cat6 also works... usually a little more expensive. Try to find a "bootless" cable -- it will fit inside the jack housing otherwise you may have to carefully trim off a plastic "boot."  Shielded or unshielded is fine; straight-through is what you want and probably your only option. We purchased them from https://www.lanshack.com/Cat-5E-Outdoor-Direct-Burial-Rated-Custom-Ethernet-Patch-Cable-Made-in-USA-by-QuickTreX--P9788. We've also bought some for other projects from https://www.cablesforless.com/custom-cat5-direct-burial-cables/ which feel a bit nicer in the hand. If you need to replace the waterproof RJ45 jack on the scarecrow bucket or control panel, make sure the one you get mounts in a M20 hole such as https://www.amazon.com/PENGLIN-Waterproof-Connector-Ethernet-Outdoor/dp/B0B1CQYF8L/