I have (finally) made a proper PCB and am offering an LVD / battery saver kit.

This is based on the Custom Arduino-based LVD, but incorporates a 60A N-channel MOSFET. For simplicity's sake, this has a single MOSFET for switching on the ground side. While the components are rated high, it's probably best for relatively low draw (~5A). For high-draw components you can easily use the LVD to fire an automotive electromechanical relay and drive as much current as you like!

Type

A simple, static Stack of int. If you can spare the additional ~1k FLASH for StackArray or StackList, please use them. ATtiny parts are tight on FLASH, and I didn't need the extra functionality.

This is primarily used in Flasher to print most-significant-digit first, and store additional high/low pulses.

An LED "flasher" to expose unsigned int values via single LED, in cases where Serial is unavailable (e.g. on ATtiny parts, or in field-installed modules). This code is used in the Custom Arduino-based LVD

Uses TinyStack for an internal data structure.

Introducing the Commuter Brake:

Tie this around a brake lever to maintain light pressure on the front brake. This immobilizes the wheel and helps keep the bike from moving while propped up in a train or against a tree.

The brake is a short loop of nylon shock cord. Adjust it once to fit, and just slip it on / off as needed. The cord will be tight enough to maintain brake pressure, but also loose enough to allow you to release pressure (squeezing near the top of the hood) to relocate the bike.

Availability

for $1 I'll mail you a few. For $0 I'll hand them over, just find me.

Works on any type of handbrake


Compatible with disc brakes!

Emergency Repairs


The Commuter Brake, temporarily repurposed to secure a broken rack.

Update: We went with Custom Arduino-based LVD solution for this project.

The LVD Project is great, but relatively complex -- overkill for some applications. A more static circuit could be made with a zener diode, a signalling LED, and possibly a relay (for actual switching)

This is a zener-based circuit. An interesting reference is at http://pubpages.unh.edu/~aperkins/pdf/Misc-devices/unijunction.pdf --- highly recommended, but a bit technical.

A subset of an LVD (or a starting point) is just the "detection" (signalling) portion:

A prototype is about the area of a dime, with only 6 components:

This working model lights up right at 10.7v, indicating sufficient voltage for a specific application (SLA batteries with 15w fluorescent load).

Parts

P/NDescription
743550 10v zener diode, 5240
38359 3904 NPN transistor
333201 small LED (t1)
691340 100k Ohm resistor
691104 10k Ohm resistor
690865 1k Ohm resistor

Wire the LED-side of the transistor over to an appropriately-sized relay and you get the actual protection circuit. For better usability, green and red LEDs can be added on the open/closed size of the relay as well, to indicate low/high voltage conditions.

For lower-power applications I found a Bestar BS-102B relay -- 12V SPDT, switches 2A, and draws less than 200mW.

This email address is being protected from spambots. You need JavaScript enabled to view it. (or comment in G+) if you're interested in this as a kit or working unit. The PCB is annoying to source, but the rest of the parts are $18 for qty 100 via Jameco

This is a robust low-voltage detection setup, managed with a PICAXE 08M2 microcontroller (and some supporting hardware) to manage the accessories on my motorcycle. Schematics, parts, and source code are at the end. I've also made a Custom Arduino-based LVD with the 8-pin ATtiny45, and A Simpler LVD with no microcontroller and static detection.

This project has also been set up as a "kit" at clubjameco.com. This email address is being protected from spambots. You need JavaScript enabled to view it. if you have any questions.

Background

The problem: motorcycle batteries are barely strong enough to start a bike on the first/2nd try. The lowest-possible load on my battery is about 80-100W. High-beams are another 65W, auxiliary lighting is another 70-100W, heaters are 18-36W, plus a few watts here and there for things like brake lights, iPhone chargers, etc.

On my Bandit, this extra load can drain the battery in under 30 seconds, low enough that it can't be started. On a related note, I'm getting pretty good at push-starting this bike.

Dad stole my rigging knife w/ marlinespike. After turning over my house looking for it, I asked him about it when we met in the FL Keys. He said it was back at his house in Neptune Beach, so I decided to try and make one.

We went to Marathon Marina & Boatyard and found one piece of recycled "teak" -- basically a 2x4 about 8' long, weathered on one face and with holds drilled at regular intervals. We had it cut down to a few smaller pieces and I brought some home with me.

View the album on Flickr