BikeEverest
Introduction: BikeEverest
A champion biker from Alaska--<PERSON>--in a 21-hour nonstop stretch over the this Memorial Day weekend, made 13 trips up and down a 9-mile stretch of local Hatcher Pass Road to complete the Everest climbing challenge. The goal for participating cyclists: ride the hill of their choice over and over until they climb 29,029 feet — the height of Mount Everest. This is a talented biker who held the woman's record for the Continental Divide Race as well as first place finish in the unsupported Trans Am Bike Race. We are very proud of our slim local sports talent pool. To emulate her effort I thought it would be fun to just notch off a few feet here and there and over the course of days, weeks, or months mount my own challenge. For those of you interested in keeping track of arbitrary heights gained with your bike in your casual weekend rides I have provided instructions on how to build a monitor that will eventually announce to the world that you too have completed the Everest Challenge!
The device is rechargeable and sleeps most of the time and has a E-Paper screen that provides you with diverting pictures of the mountain.
Step 1: Gather Your Materials
This build is incredibly simple and easily made. The ease of putting it together is based on the nesting features of Adafruit Feather boards and screen. The only additional add-ons are a switch for power, a rechargeable battery and the newly released BMP 388 altimeter.
1. Adafruit HUZZAH32 – ESP32 Feather Board $19 You can use a different Feather -- the advantage of the ESP is it goes to sleep so easily.
2. Adafruit 2.13" Monochrome eInk / ePaper Display FeatherWing - 250x122 Monochrome $21 You can also use the three color one with red to jazz it up.
3. Adafruit BMP388 - Precision Barometric Pressure and Altimeter--$9
4. 600mah Rechargeable battery --- $2
5. On/Off switch --$1
Step 2: 3D Print It
The case is made in two pieces that are easily printed without support in PLA. PETG may hold up to the elements a little better--and I would use it preferentially if you live in someplace hot like Tucson --- doing your Everest going up Mt Lemon! The insets are designed to take 3mm metric heat inserts into the base. The Screws go through the slightly undersized holes in the screen that must be enlarged with a 3mm bit. If you want a slightly bigger battery you can increase the depth of the upper case with little trouble. 33
The side port for accommodating programing and charging of the battery is built into the file. The flattened area at the back of the base is to attach the mount for the bicycle handlebar. The line knurling on the back of the case is done by adding a screw pattern in an early step.
Step 3: Wire It
There really isn't much to the wiring of this device so I didn't include a wiring diagram. The ease of just soldering some male headers onto the ESP32 allows you to easily mesh it to the receiving side of the E-Paper screen. This connects all the complicated pins in the SPI interface along with all the pins to control the build in SD memory card. The only thing that requires wiring is the BMP 388 which comes from Adafruit on a I2C breakout board. Nicely, you don't have to add any pull-ups to make it work. Just solder wires to the Power, Ground, SCL and SDA and attach them to the female hook-ups on the Feather E-paper screen. I used some male header pins and just soldered the connector wires to them and pushed them home. A few dabs of hot glue holds these connections in place to the 3V, GND, SCL and SDA on the main board. (You will probably become bored with this device soon and want to build something else with these expensive components.) The battery is connected with JST connector to the ESP32 with a switch placed on the Power line to turn the device on and off. To charge the unit you must have it on the ON position.
Step 4: Build It
The BMP 388 fits very nicely nested between the Feather E-paper screen and the ESP32. The case has the battery tucked at the bottom and the only modifications are for your preferred switch mounting position. You can easily add a more subtle slide switch. The case is not designed to be waterproof although you can make additional modifications in the design to help prevent water ingress. The E-paper screen is held in place with the 3 mm screws going through the modified screen holes and supported by small spacers underneath the screen. 611