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The collection of information useful for biking with a Neo.


Bike Mounts

Openmoko mtb 01.jpg

Power Supply

If you want to keep the GPS running and have the screen always on or staying on with a long timeout, you'll need a way to supplement power.

Charging via hub

Connecting a hub (Nabendynamo) like the SON to a self-made or prebuilt charger can supply your device while biking.

The FreeRunner has three different charging modes: 100mA, 500mA and 1A. 100mA seems to be too low, as it is said, that the FreeRunner draws 100mA current even when it is switched off. A hub dynamo provides 500mA. If you want to use your lights while charging you need to connect the lights in series to the charger. At least the SON will increase the voltage and still delivers the same current. But you need a bypass circuit in case of less current draw of the charger when the battery is full.

Using an USB connection with that ID resistor for 1A mode provides the advantages that the charging mode is automatically correct. This might be important if you stop frequently and so cause some kind of power "disconnect" and you do not want to select the charge mode all the time. 1A mode does not harm the hub dynamo but if the dynamo can provide the 500mA also at higher voltages, you can gain more charge current than in 500mA mode if you have a switching regulator. For example if the dynamo would provide 10V 500mA and you would have a 100% efficient regulator, you would have 5V 1A.

Commercial Chargers

self-made chargers

Will fry FR nevertheless, as FR might stop to take up any current and then the 6V still creep thru the diode.(jOERG)

Linear regulator above might be replaced by DE-SW050.


If you decide to try solar, it's recommended to get a flexible panel and attach it to your backpack or something like that. One nice advantage here is it might also charge even when you're not moving. It's unlikely anything below 7 watts will keep things running. (5v * 1A = 5W).

It might work with an dynamo outside the hub like the one on the reelight, but it looks like their coil produces only 3vAC so it makes sense to use a custom coil.

An extra battery like Rechargeable USB Emergency Power Backup Pack 2400mAh $14.43 can also be useful for extending battery life-time.

Software for biking

See also

Heart Rate Monitor

According to mailing list discussions some heart rate monitors use ANT. Due to the modern chip cases building a reliable homemade receiver seems to be difficult.

HRM Links


since 0.99.4 TangoGPS support Zephyr HxM heart rate monitors

Other Hardware

  • oBiCo - An open bicycle linux computer - seems to be alive, but nothing there yet.

External links

Personal tools