Human Electric Trike Thesis

Design of an electrically assisted human powered trike

Archive for the ‘Electronics’ Category

Installed drain brain

Posted by Bob Dold on Sunday, October 15, 2006 9:10 PM

Received the Drain Brain on Thursday and spent today installing it on the X1000 scooter. Installation requires splicing the shunt between the batteries and controller and hooking up a wheel sensor. The picture below shows the unit installed on the handlebars:

 

The drain brain displayes the speed, watts, battery voltage, and distance traveled. It also stores the maximum current drawn and maximum wattage. After using it for a couple charge cycles it can calculate the miles left on a charge. After a brief test, it confirmed the maximum current was limited to about 30 amps, this occured when accelerating up a slight grade.

Advertisements

Posted in Electronics | Leave a Comment »

USB Current Logger

Posted by Bob Dold on Monday, October 2, 2006 10:58 PM

In order to track motor current vs. time I plan on using one of these $70 Omega units http://www.omega.com/ppt/pptsc.asp?ref=OM-EL-USB-1…  and then sync the data with the trip data from the Garvin Edge 205. I can measure the current using a shunt resistor using these directions provided by Dr. KJ:

 

DC Current Measurement

Place a shunt resistor in the current path and measure the voltage over the resistor.

Note: This technique can only be applied to DC currents, not AC 

The value of the shunt resistor must be chosen carefully as follows:

Step 1. Find the maximum current

You may know this value (in Amps) already, but if not it can be found from the power rating of the motor (or whatever the load is):

(Amps) = Power (in Watts) / Voltage

In your case: I = 30 A

Step 2. Find a suitable value for the resistance

Make sure that the resistance is not too high

Too much voltage will be dropped over the resistor, taking power away from its actual purpose (in this case driving the motor). As a guide, try to avoid dropping more than 1% of the available voltage over the shunt. In the example above 1% of 24 V is 0.24 V

If the resistance is too low

The voltage seen by your A/D will be too low, so the current measurement will be less accurate and noisy or stepped. Avoid this by ensuring that at least 0.1 V appears over the shunt at maximum current. In the example above the voltage over the shunt should ideally be between 0.1 V and 5 V, when the maximum current is flowing. Experimenting with resistance values R in the formula:

Voltage(V) = I R

leads to the choice of 0.01 Ohms, which will develop 0.3 V at 30 A.

Step 3. Calculate the Wattage required for the resistor

We don’t want the resistor to burn out, so fit a suitably high wattage one using the formula:

Power(Watts)= I2 R

In your example, Power = 30 x 30 x 0.01 = 9 W, so you’ll fit a 9 W resistor. Once this is connected up you can configure the acquired voltage to be scaled directly in amps instead of in voltage.

 

OM-EL-USB-3
VOLTAGE DATA LOGGER
Range: 0 to 30 Vdc
Resolution: 100 mV
Accuracy: ±1%
GENERAL
Memory: 32,000 voltage readings
Logging Interval: 1 seconds to 12 hours
Operating Temperature Range: -25 to 80°C (-13 to 176°F)
Alarm Thresholds: High/low alarm thresholds selectable in software
Start Date/Time: Selectable in software
Status Indicators (LEDs): Red and green
Power: 12 AA 3.6 V lithium battery (included)
Battery Life: 1 year typical (depends on sample rate, ambient temperature and use of alarm LEDs)
Weight: 57 g (2 oz)
Dimensions: See dimensional drawing

OM-EL-USB-4
CURRENT DATA LOGGER
Range: 4 to 20 mA
Resolution: 0.1 mA
Accuracy: ±1%
GENERAL
Memory: 32,000 current readings
Logging Interval: 1 seconds to 12 hours
Operating Temperature Range: -35 to 80°C (-31 to 176°F)
Alarm Thresholds: High/low alarm thresholds selectable in software
Start Date/Time: Selectable in software
Status Indicators (LEDs): Red and green
Power: 12 AA 3.6 V lithium battery (included)
Battery Life: 1 year typical (depends on sample rate, ambient temperature and use of alarm LEDs)
Weight: 57 g (2 oz)
Dimensions: See dimensional drawing

Posted in Electronics | 2 Comments »

DRAIN BRAIN – EV TECH

Posted by Bob Dold on Monday, October 2, 2006 4:58 PM

Drain Brain current and speed gauge:

DRAIN BRAIN – EV TECH

Posted in Electronics | Leave a Comment »

Garmin Edge 205 GPS

Posted by Bob Dold on Friday, September 29, 2006 2:54 PM

While looking for components to set up a data acquistion system I came across this $200 bike GPS with logging software. I think this may do the job in logging speed and grade better than trying to fabricate my own using and inclinometer and data acquisition board. To track current I may still need a current logging system that I can sync to the Edge results. Cheapest inclinometer I could find was $150 + $109 USB data board which still requires software, a way of measuring speed, and carrying around a laptop on the trike:

Sample plot from GPS software:

Take your ride to the next level with the Garmin Edge 205 – Garmin’s GPS-enabled personal trainer and cycle computer. Perfect for touring and the trails, the lightweight Edge is the ultimate fitness partner. With the easy-to-use Edge 205 on your bike, you always know where you’re going and how far you’ve gone. For advanced cyclists, the Edge 305 is available with either a heart rate monitor or a wireless speed/pedaling cadence sensor to help you achieve your personal best.

The Edge 205 measures speed, distance, time, calories burned, altitude, climb and descent, plus much more. 205 features include:

  • Easy-to-install – no calibration required. Just snap it in the included bike mount and go
  • High-sensitivity GPS receiver – knows your position even in tree cover and canyons, making it extremely reliable for navigation
  • Customizable cycle computer – shows up to eight different data fields for continuous feedback
  • Virtual Partner – lets you “race” a virtual competitor, making training fun
  • Courses – lets you “race” against a recorded course to try to match previously set speeds at every point along the way
  • Auto Pause – pauses the training timer when you slow down below a specified speed and resumes when you speed up again so you can focus on your ride
  • Training Center software – gives you the ability to create workouts, manage and download courses, and create a detailed post-ride analysis that charts your performance

With its waterproof, sleek design, the Edge is the perfect companion on any bike, and attaches to either the stem or handlebars. Its rugged case frames an easy-to-read, large, backlit display that can show up to eight different data fields along with altitude and a map view.

Included Training Center software gives you the ability to overlay your ride data onto a course map. It offers interactive analysis tools that measure your speed, distance, climb, and descent against varying terrain, elevation and more. Create and schedule custom workouts or use workout templates and download to the Edge.

Edge 205 Features:

  • GPS: High-sensitivity SiRFstarIII receiver
  • Antenna: Built-in patch GPS antenna
  • Weight: 88 g, 3.1 oz.
  • Display: 1.17″W x 1.44″H, 128 x 160 pixels, 4-level grayscale LCD with backlighting
  • Unit dimensions: 1.75″W x 3.7″H x .9″D (44 x 94 x 23 mm)
  • Waterproof: IEC 60529 IPX7 standards (submersible in one meter of water for up to 30 mins.)
  • Battery: Up to 12 hours (typical use); rechargeable internal lithium ion
  • Track log: 13,000 track points

Package Includes:

  • Edge 205
  • Bike mount
  • Training Center CD
  • A/C charger
  • USB PC interface cable
  • Quick reference guide
  • Owner’s manual

Specifications

Features

  • Training data: Speed, distance, cadence (305 only), heart rate (305 only), lap by position, elevation, average and max speed, calories burned, climb and descent
  • History: Automatically records up to 1000 laps. Download to your PC using included Training Center software.
  • AutoPause: Automatically pauses the training timer when you slow down below a specified speed; timer resumes when you speed up again
  • AutoLap: Automatically triggers a lap every time you pass a specified location or travel a preset distance
  • Courses: Race against a recorded course and previous raced speeds at every point along the way. Combine Courses and Virtual Partner features and race an opponent that varies speed while climbing hills and navigating turns.
  • Virtual Partner: Race against a virtual competitor. Depicts a digital cyclist (desired speed) in relation to your real-time speed and shows how far ahead or behind you are.
  • Alerts: Speed, time, distance, heart rate (305 only), cadence (305 only)
  • Calories: Calculates calories burned based on user profile, performance data and altitude changes
  • Training Center: PC-based software (included) overlays ride data on a map and graphs speed, pace, heart rate, cadence and elevation. Create and schedule custom workouts or use workout templates and download to the Edge.

Navigation features

  • Receiver: SiRFStarIII high sensitivity receiver
  • Mark location: Mark and save up to 100 locations
  • Find location: Look up and navigate to stored locations
  • Back to start: Navigate back to starting location
  • Track log: 13,000 track points

Physical

  • Size: 1.75″W x 3.7″H x .9″D (44 x 94 x 23 mm)
  • Display: 1.17″W x 1.44″H (29.65 x 36.69 mm), 128 x 160 pixels, 4-level grayscale LCD with backlighting
  • Weight: 88 g
  • Waterproof: Waterproof to IEC 60529 IPX7 standards. All components are submersible in 1m of water for 30 minutes
  • Battery: 800 mAh rechargeable lithium-ion battery; 12 hours typical use
  • Antenna: Internal patch
  • Mount: 2-piece mount with zip ties; mounts on stem or handlebars
  • PC Interface: USB

Sensors

  • Heart rate: Robust wireless transmission; sends heart rate data to Edge via chest strap
  • Speed/cadence: Self-calibrating wireless sensor mounts to bike’s rear chain stay. Wheel magnet mounts to rear wheel for speed; cadence magnet attaches to crank arm.

Edge series comparison guide

Here’s how the units are different:

  • Edge 205 (this page):
  • Altitude: GPS based
  • Elevation profile: yes
  • Cadence: no
  • Heart rate: no
  • Edge 305HR:
  • Altitude: barometric altimeter
  • Elevation profile: yes
  • Cadence: yes with purchase of speed/cadence kit
  • Heart rate: yes
  • Edge 305CAD:
  • Altitude: barometric altimeter
  • Elevation profile: yes
  • Cadence: yes
  • Heart rate: yes with purchase of heart rate monitor kit

Product Shots:

Posted in Electronics | Leave a Comment »

Data acquisition system

Posted by Bob Dold on Thursday, September 28, 2006 12:11 PM

In order to evaluate the performance of the completed trike I plan on putting together some instrumantation to measure it’s performance. Variables I would like to log are the following:

 Speed

Time

Grade

Motor Amps

From these I can compare the actual performance to the predicted performance calculations I have made. To recored the data Dr. K.J pointed me to this $109 USB DA board: http://www.measurementcomputing.com/cbicatalog/cbiproduct_new.asp?dept_id=412&pf_id=1535&mscssid=JCM5JCEEDRK38KSPRT8QX1R3D4TK5GC7

pmd-1208lssmall.gif

This will plug into a laptop and allow recording of up to 8 analog inputs – currently I will need only three:

speed – optical sensor

grade – inclinometer

amps – measure voltage with shunt

The time can be tracked within the DA module, it is possible I could use additional inputs for TC’s or strain gages.

Here are some links to different inclinometers:

http://www.riekerinc.com/ElectronicInclinometers.htm

http://www.cfxtech.com/

http://www.usdigital.com/products/incremental-inclinometers.shtml

Posted in Electronics | Leave a Comment »

S1000 Motor pics

Posted by Bob Dold on Tuesday, September 19, 2006 1:07 PM

Here are some pictures I found on the web of the Currie 1000 Watt motor that will be used on the trike, I should have the real thing on Friday 9/22:

Posted in Components, Electronics | Leave a Comment »

Alternate Batteries

Posted by Bob Dold on Monday, September 18, 2006 9:07 PM

Here are a couple of other alternatives to the sealed lead-acid batteries with better capacity per pound available from http://www.texaselectricbikes.com/contact.htm:

LITHIUM POLYMER BATTERY 36 VOLT-15 AMP HOUR
$749.00

THE WAIT IS OVER!!!
WE HAVE BEEN WAITING SINCE 1985 FOR A BATTERY THAT WAS GOOD ENOUGH FOR THE LIGHT ELECTRIC VEHICLE MARKET. WE TESTED PROTOTYPS 10 YEARS AGO, AND FINALY THEY ARE IN PRODUCTION.
THIS IS THE BATTERY FOR ELECTRIC BIKES, ELECTRIC SCOOTERS AND ANY OTHER LIGHT ELECTRIC VEHICLES THAT DEMAND LOTS OF POWER.

  • LITHIUM ION POLYMER TECHNOLOGY
  • BUILT IN BATTERY MANAGEMENT
  • 36V
  • 15 AMP/HOUR
  • 60AMP MAX
  • 40A CONTINUOUS
  • 10Lbs.(NOT A MISPRINT)
  • 9-1/4″ X 5-1/4″ X 3-5/8″
  • FAN COOLED 4A CHARGER INCLUDED
  • CHARGER ACCEPETS 100~245V AC INPUT
  • >500 CYCLE LIFE
  •  

    NiMH 30 VHF Series Battery
    $899.00

    SAFT NiMH 36V,13Ah VH SERIES Ni Metal Hydride Battery

  • 36 VOLT
  • 13Ah
  • 7 W x 3 D x 12 T
  • 18 LBS.
  • INTERNAL BMS
  • BUILT -IN SOC, TEST SW
  • COM PORT FOR REMOTE SOC
  • BUILT-IN FUSE
  • F CELL CONSTRUCTION (30EA.)
  • Posted in Electronics | Leave a Comment »

    Odyssey PC925 Battery

    Posted by Bob Dold on Saturday, September 16, 2006 8:34 PM

    Because the Optima D51 batteries are no longer made, the Odyssey looks to be the next best choice to fit in the frame – with the 1000 watt currie motor three will be required. Available from http://www.batteryweb.com/odyssey-detail.cfm?Model…

    Odyssey Batteries PC925

    PC925

    Voltage: 12 V  
    CA: 925 AH
    CCA: 470 AH
    AH: 27  
    Warranty (years): 3
    Hardware: M6 – Female Brass
    Replaces: Unique
    Weight: 26 Lbs
    Length: 6.5
    Width: 7.0
    Height: 5.0

    Price: $98.88

    Posted in Components, Electronics | Leave a Comment »

    2006 Schwinn Stealth – Donor scooter

    Posted by Bob Dold on Friday, September 15, 2006 8:26 AM

    In an effort to produce a lower cost drivetrain I plan on using the drivetrain on this scooter to power the bike, the Stealth has a gearbox whch I will connect with a chain to the rear wheel to provide the necessary gear reduction. I plan on replacing the batteries with a higher capacity set in order to get the desired range of 50 miles.

    2006 Schwinn “Stealth” S-1000 Full Suspension 1000 Watt Scooter – In Stock August 1, 2006 – Free S/H

    Posted in Electronics | 1 Comment »

    Current Cycle Bikes – Crystalyte Phoenix Hubmotor

    Posted by Bob Dold on Thursday, September 14, 2006 1:37 PM

    Link to hi-power hub motor bike:

    Current Cycle Bikes/info@currentcyclebikes.com

    Posted in Electronics, Performance | 1 Comment »