Cable and switch recommendations for dynamo headlights?

[Alex Wetmore]

I have my circuit done and most of a housing built. The only thing that I'll need to finish up my headlight project is a good waterproof switch and good cable.

Does anyone have recommendations (hopefully something easy to find at Digikey or Mouser in reasonable quantities)? I really like the coaxial cable that Schmidt uses and haven't been able to find a similar one. Coaxial cable is nice because you get a easily sealed hole. Their cable isn't too large and seems to be very durable.

Paired 18ga or 20ga "speaker" cable is what I've used in the past, but it doesn't look as nice or seem as flexible and durable.

I'd like for the switch to have a through hole mount, not be very large, and be easily sealed. I'm not particular about the type of switch.

alex

 

[Eamon]

What configuration of switch do you need? I looked at your circuit and didn't see it.

C&K do nice little switches in many different configurations. Digi-key will provide, and probably mouser as well. I've seen "boots" available for their toggles as well.
http://dkc3.digikey.com/PDF/T083/2013-2016.pdf
http://dkc3.digikey.com/pdf/marketing/APMHex_Boot_to_toggle.pdf

Martin turned me on to Grayhill, who do a lot with MilSpec and hostile environments. I've gotten a couple of their rotary switches, and they're quite well done. Digi-Key carries some of their stuff.
http://www.grayhill.com/index.html

I'm no help on cables, the connectors I like don't talk to Co-Ax.

Eamon

 

[Alex Wetmore]

I need a switch between the dynohub and the headlight. A SPST is fine. DPST would let me shut off the standlight as well.

What connectors do you use? My dream is a durable micro connector that fits through a 5mm hole (wiring eyelet on the back of a fork blade), but I haven't found them (and they probably don't exist).

alex

 

[Eamon]

Alex,
Molex is making a really small (31x8) locking "splash-proof" connector. I can't find a good image of them, but drawings and specs are here:
http://www.molex.com/molex/products/...cts&Lang=en-US.

I'm using them as disconnects for the power leads on dynamo hubs. They're not fully waterproof like a Deutsch or a Tyco, but they're not 50x16mm either and much cheaper. inserting the wires is a little fiddly but not hideous, and the lock is pretty secure.

My intent was to be able to switch lights back/forth between bikes without having to pull spade connectors. I applied a little silicon grease to the sliding surfaces, and a tiny dab of copper anti-seize to the contacts. Me like.

I have seen nothing smaller that even pretends to be splashproof, let alone immersible. There are some (Fisher and Lemo) that are higher-tech and probably lock more securely, but they're much larger and rather pricey.

I had to get the Molex(s) through Heilind electronics, and the contacts from Digi-Key. Most vendors are BO'd for them, and I had to dig about on Molex's site.

I think that they probably would fit through an older-style oval wiring loop. The 5mm current style, not so much.

Eamon

 

[Steve K]

I need a switch between the dynohub and the headlight. A SPST is fine. DPST would let me shut off the standlight as well.

What connectors do you use? My dream is a durable micro connector that fits through a 5mm hole (wiring eyelet on the back of a fork blade), but I haven't found them (and they probably don't exist).

alex

hi Alex,

A switch? Once I made my first LED headlight, I realized that I didn't need a switch anymore. Do you really need one?

If you do decide to use one, your choices are a bit limited. I've used a SPST push-button switch with boot, purchased from Digi-key. It was designed to be panel mounted, and I just mounted it to a small plate. I used Plasti-dip to seal up the wires on the back.

There are military switches available....somewhere. Might check the larger distributors like Allied or Avnet or Newark. These switches tend to be very well engineered and very expensive.

I have to admit that I don't use connectors. I just use a set of pins & sockets wired just a few inches from the Schmidt connector spades. The pins & sockets are Deutsch machined contacts that are also nickel plated. They are insulated and strain-relieved with heatshrink tubing, and use dielectric grease to reduce moisture entry. Of course, I don't live in Seattle either, so you may need a real connector with real seals. Just be sure to use the right diameter wire insulation to work with a connector's seals.

For wiring, I use basic 22 ga. wire with teflon insulation. To keep it semi-tidy, I twist the wire pair. Schmidt's coaxial wire is pretty nice and tidy, but I have no idea where to buy it. You might check the web site of the major wire manufacturer's, such as Belden ( http://www.beldencdt.com/ ) or Alpha Wire ( http://www.alphawire.com/ ).

regards,
Steve K.

 

[yellow]

I ve heard and read, that one does ot notice any difference between ON and OFF with hub dynos
... wondering that because the energy for the light has to be produced, or not?

When it is right, just add no switch at all, one part less to fail

 

[Steve K]

I ve heard and read, that one does ot notice any difference between ON and OFF with hub dynos
... wondering that because the energy for the light has to be produced, or not?

When it is right, just add no switch at all, one part less to fail

The difference between On and Off is very small for the Schmidt dynamo that I use. Personally, I can't detect a difference in the drag. However, I've heard of randonneurs that want to turn the light off just to maximize efficiency.

When I used an incandescent light, it was important to turn off the light in the daytime. If/when the bulb burned out, the protection diode had to absorb all of the dynamo's power, and it could only do so for a short time. In the daytime, you can't tell when the bulb blows, and the protection diode will probably fail too.

As a commuter, I decided to leave my LED headlight on in the daytime to increase my visibility. Based on reports from others, it does improve the visibility significantly. The lack of a switch does improve reliability, but I have to admit that my previous switches never failed.

regards,
Steve K.

 

[mschol17]

Call Peter White for Schmidt coax.

 

[Alex Wetmore]

I do feel like I can feel the difference between On and Off with SON and Shimano dynohubs. It isn't noticable at normal speeds, but there is a small vibration or notchiness that can be felt above 20mph. Since I live in a hilly area I'm often going 20mph downhill.

I also like being able to switch off the standlight so that I don't get a lot of people stopping by and telling me that I left my lights on.

Neither are big deals, but having the switch doesn't hurt.

alex

 

[Eamon]

I can definitely feel the difference between SONn and SONff. The vibration travels right up the fork and into the bars. I can even tell the diff between high and low.
The light stays off during the day. Efficiency and smoothness, among other reasons. I also like the ability to use it as a deliberate warning to drivers by toggling on/off quickly.
The only time I can feel the drag is when I'm really (like 400k) tired.

Eamon

 

[Steve K]

I also like being able to switch off the standlight so that I don't get a lot of people stopping by and telling me that I left my lights on.
..<snip>..
alex

I've got switches for my standlights since I use nicad AA cells. Otherwise, they run for hours, and it's not good to completely discharge batteries.

If you want to shut down the standlight, that'll require a separate switch from the one used to shut off the light itself. Or were you just going to have a switch wired directly in series with the LEDs instead of in series with the dynamo?

Steve K.

 

[Alex Wetmore]

A single DPST switch with one pole for the AC input and one pole shorting out the ZXSC310's shutdown pin seemed like it would do the trick.

alex