The Brown Design Workshop (BDW) is a makerspace made available to the community at Brown University and the nearby Rhode Island School of Design (RISD). The space houses two laser cutters, several 3D printers, soldering irons, many tools for working with wood and metal, and now a vending machine supplying electronics such as arduinos. I got the idea for the vending machine from one I saw at Brigham Young University's electrical engineering department that dispenses LEDs and such. I've also learned of a similar machine at a makerspace at Dartmouth College.

I spent a lot of time finding inexpensive components for some arduino summer courses I taught last year. I wanted a way for such parts to be readily available for makers here. A fellow grad student encouraged the vending machine idea and helped me pick up the machine.

The goal for this machine is not to make money, but to pay for itself and its contents so that it can remain in the BDW for years to come. Hopefully many students and others in the community can be introduced to the wonderful world of arduino because of this project!

Step 1: Obtain a Vending Machine

The first step is to obtain a suitable vending machine as cheaply as possible. If you're feeling adventurous, you could also make your own. Here are a couple (1, 2) of instructables about how to do that. I was fortunate to find mine on Craigslist for $300. While it took another $100 to rent the truck to bring the machine to the Brown Design Workshop, these costs were recovered within a few months of operation. I actually found that I spent more money getting the machine stocked, which leads me to my next step...

Step 2: Finding Things to Sell

At universities there are often stockrooms that keep stores of chemicals, petri dishes, gloves, etc. This machine is meant to be a sort of stockroom for the engineering and maker communities at Brown and RISD. The goal is to provide electronics parts and components as cheaply and conveniently as possible. While my focus is on electronics, you could also focus on other things, like paint and glue, for example.

In order to keep things cheap, I order most of my stock through ebay. AliExpress is good too in many cases, but I have better luck with my ebay purchases actually showing up. I type in a search term like "Arduino SD module", look at only the "Buy it now" offerings, then sort them by the lowest price+shipping. Ebay is so competitive that the prices you can find beat most other sources. The packages take a few weeks to arrive sometimes, so it's good to monitor the stock and place orders early enough that they arrive by the time you run out of what you have. Eventually I hope the machine will bring in enough money so that the orders can be made in bulk and not as often. I only mark the items up by a dollar or two so they stay cheaper than Amazon while still paying for themselves and the machine. In the end, makers are able to get what they need right away.

Step 3: What I Sell

I try to carry the essentials for electronics projects, as well as some fun add-ons. Many of the parts don't fit well in the vending slots. I have improvised by cutting out pieces of cardboard that I staple the plastic packages to.

I currently carry/have carried:

Arduino clones (Uno, Nano, Mega, Pro Mini)

ESP 8266 ( NodeMCU version)

ATTiny85

Dupont cable (20cm, FF, MM, MF)

USB cables ( for programming the arduinos)

Resistors, Capacitors, LEDs, etc.

Batteries (only 9V so far)

USB adapters

USB drives

Raspberry Pi (version 3 model B as well as Pi Zero)

Motors (DC, steppers, 9g servos, high-torque servos)

Breadboards (both mini and full-sized, also breadboard power supplies)

FTDI boards for programming the pro minis

LCD and OLED screens

Multimeters

Keypads

NRF24L01 Modules (radio tranceivers)

DHT-11 (temperature and humidity)

DS3231 Real Time Clock

Relay Modules

PIR motion detector modules

RFID kits for arduino/rpi

HC-05 Bluetooth modules

Soil moisture sensors

Accelerometer/gyro modules

WS2811 RGB LED strips

ThermoMorph prototyping plastic

Step 4: Tracking Progress

It is very important to track your progress as you go. I keep a spreadsheet where I record every order I place for the vending machine and how much money comes in. This lets me know how much I can afford to purchase new stock.

The machine was installed in July 2016 and sat basically empty until the start of the school year. As of this writing in June 2017, the machine has brought in $1728.30 in income. In addition to the cost of the machine and transport ($392.54) I have spent $1188.69 on stock. Add in the cost of quarters for change and right now I have about $40 to spend on new stock to keep the machine at zero profit.

I haven't kept great records of what has sold, however, which leads me to ideas for future improvements...

Step 5: Ideas for Future Improvements

Wouldn't it be great to make the vending machine smart? Someday, I would like to either remove the old electronics or interface with them in order to:

- Send me a text anytime something sells.

- Accept credit card or paypal payments. No one wants to buy a $40 raspberry pi with $1s and $5s!

- Be able to vend items remotely.

- Have inventory monitored automatically. Send me weekly emails with what I should order.

There are a number of ways to accomplish these goals. I'm a big fan of Blynk and have used it for my home automation system, so that's a great option for remote features. I've also considered using a Square reader in combination with a single-board computer running android. Eventually there could be a beautiful app running on a tablet, which allows multiple items to be selected and paid for, before all the ordered items vend simultaneously. Cool!

Step 6: Get Your Own!

I encourage you to try such a project for your local makerspace! It can be so nice to have affordable components right there when you need them. I've actually had to get components for my own projects from the machine several times.

Depending on the traffic in your makerspace, a machine can pay for itself before long. You can even put snacks in the machine to help increase the revenues. One thing I would add is that you should view such a project as a labor of love. Don't mark up the prices too much. Pretty much anyone who knows what the components are knows that they can get them cheaply. It's not about profit, it's about fun!