eScan <<my ES kickstarter and new product>>

Hi. I have decided to try and run sort of kickstarter on ES as the product i am making is more technical for casual folks. This first post is just a glimpse of the product and i will update it as often as i can.
First of, what it is. It is a ignition switch, expensive one, fancy one. Its mostly meant for bikes with box frame: Stealth, Phasor, Qulbix, Chaika, Boggrunner, but could be used by anyone building custom bikes.
It is a true fingerprint ignition system. It can store 200 fingerprints. It controls 2 switches. The first one is your usual ignition and the second one is 3 speed switch, more like 2 speed switch in this case.
How does it work? Pressing latching switch energizes the system, the you scan your finger, red switch LED lights up and your bike is life. You press it again, switch LED changes to green, and now your bike is in limited power mode, scan again and it goes back in full power mode, infinite loop. There are 2 users to enroll. First is Administrator, second is User. Administrator can change power mode when scanning fingerprint and User has limited power profile. Whenever User scans hes fingerprint, switch LED goes into green and limited power engages, scanning second time gives visual indication, red LED blinks twice and goes back into green, limited power. This option is good to have your kids use the bike with limited power.
Here is a prototype:







The finished product will be made out of aluminium, anodized, yet to confirm colors, black for sure. There will be no visible bolts just rounded 40x100x5mm plate with switch and scanner panel:



There will be a gasket to waterproof it from outside and if all goes good plastic cover with connector from inside.

Here is a short vid:

[youtube]PVeeVSsBmec[/youtube]

Needs 12V for power(???).
The enrollment of fingerprints is done via mini USB (Arduino based device).

I am hoping to rise some interest and basically take pre-production orders. As i always say, i am small operator and don't have too much funds to invest.
It will be probably 1 month ordering time an 3 months manufacturing to delivery.
Hope you like it

Add a pre-charge circuit that will handle 99v with fets that can handle 40a cont. and I'm in for one.

Its a ignition switch, like key switch. If you need precharge and high power switching, you should look into contactors with precharge.

agniusm said:

Its a ignition switch, like key switch. If you need precharge and high power switching, you should look into contactors with precharge.

Click to expand...

That's what I have now. Every time somebody forgets to use the pre-charge it welds the contacts shut on my big (expensive) DC contactor. HOC on my bike is 100V. It would be nice to have a device that can do both functions.

I am about to build a bike with alltrax and the way i see it from the diagram the precharge is permanently wired in parallel to contactor, so why disconect it?

P.S. Thought about this a bit. You could wire precharge resistor to latching switch and ignition (contactor control) to relay on the device. All the time you press the button, caps charge and when fingerprint is scanned no arcing will occur

[youtube]kmHlaK1tKMw[/youtube]

I am interested. Including the pre charge stuff I am more interested.

Sounds slick. I need to click your link and see if you have a ballpark price there.

Good luck man glad to see you keeping up with my opinion of you ;0)

edit - hah thought it was a kickstarter was looking for a link to it

Thank mate. No, not the real kickstarter. I'd probably had like 1 backer Too specific.
Regarding precharge. I am building up Blade for my brother. The way i will do it is i will get contactor, i will then wire precharge resistor to the power button and coil to eScan output relay. This way when you press the button resistor does its job and when the fingerprint is scanned, contactor makes connection without any sparks. DC-DC could be wired same way so there is 0 drain on the battery.

I would also want precharge and a contactor coil drive output before I would buy it.

It's a cool product idea!

Could you explain what you mean? There is an output to drive contactor coil up to 20W. Precharge I guess is done with different resistors depending on battery pack. You can connect that resistor inline with main switch. Dont know what else is needed

Hi Agniusm,

Having kids, I would be interested, and no need for precharge here. But a ballpark cost/price would be useful.

Have resolved some issues i had with relays. All is working at the moment as it should. I will revise PCB and start moving towards manufacture.
[youtube]YZVF0si_qlg[/youtube]
LED's for visual representation of relay switching, ignition and 3 speed (speed limiting or whatever)

I'd buy 3 depending on price

agniusm said:

Could you explain what you mean? There is an output to drive contactor coil up to 20W. Precharge I guess is done with different resistors depending on battery pack. You can connect that resistor inline with main switch. Dont know what else is needed

Click to expand...

In an EV with a controller that has a fair amount of low ESR/ESL cap, your contactor is weled on a the first mate with un-precharged caps. If the coil drive isn't watching the cap pre-charge voltage, ideally PWM'ing a FET with a little inductor in-series to rapidly pre-charge the caps, and the coil drive circuit energizes the relay before adequate precharge had occurred, the contactor welds.

A product I would buy would include some free PWM capable pin left on your uController driving a little 150v FET through an inductor to let it rapidly buck substantial current into 0V caps, and as they get close to pack voltage, it stops PWM'ing, which gets the caps to full pack voltage.

If you do a resistor for your pre-charge, you either end up needing a long delay only to still mate with SOME contactor arcing voltage-mismatch (not ideal).

Thanks. Any pointers where to look for good reading about fast FET based pre-charge?
Is it something like this you are talking about:
http://zeva.com.au/Products/datasheets/SmartPrechargerV1-2.pdf

Another problem using a resistor is that when you first push on the switch that powers up the scanner and pre-charges at the same time, If some dofus (like me) twists the throttle before the caps are all the way precharged, the resistor will burn up and you won't be going anywhere .

Your system needs to be able to do an quick "emergency" turn off too.

No doubt, you have the start of an excellent product

agniusm said:

Thanks. Any pointers where to look for good reading about fast FET based pre-charge?
Is it something like this you are talking about:
http://zeva.com.au/Products/datasheets/SmartPrechargerV1-2.pdf

Click to expand...

That looks expensive!

It's a long thread but I think Fechter nailed it. be sure to read to the end as there is a bit of miss information here and there. :wink:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=40142

nicobie said:

Another problem using a resistor is that when you first push on the switch that powers up the scanner and pre-charges at the same time, If some dofus (like me) twists the throttle before the caps are all the way precharged, the resistor will burn up and you won't be going anywhere .

Your system needs to be able to do an quick "emergency" turn off too.

No doubt, you have the start of an excellent product

Click to expand...

You need to scan your finger for the controller to get some power into logic. Nothing will happen if you twist the throttle when push switch is engaged. After scanning the fingerprint system goes active.

Went quick through that thread. From the first glance its a switch and precharger, is it? Itas too bulky.
I found this circuit:

This doesn't look too big. Yes, it's a switch and precharge.


http://endless-sphere.com/forums/download/file.php?id=150434

Neither if those pre charge circuits are ideal IMHO. If they involve pre-charging through resistors still, they are not that great of a design.

An inductor and a FET are the working parts to use to make a proper precharge that is both fast and throughly pre-charges in minimal time.

I'd listen to Luke ^

You could probably start with something like Fechter's FET switch circuit, add an inductor and a shunt, and just PWM it on a curve controlling the width of pulses, longer and longer each time, based on the current sensed thru it. Or if it precharges thru the regular system shunt (most probably would) then just measure the current off that.

Thought about integrating pre-charge here and there and decided not to integrate. There are few pointers why. First, it will make the already expensive device even more expensive. 2. it will make it bigger and 3. there are 8 wires comming out and pre-charge wil bump it up to 12.
After all it is fancy ignition switch and I have not seen ignition with pre-charge yet. I will think about developing separate pre-chatge device as an addition to my eScan switch.

agniusm said:

Thought about integrating pre-charge here and there and decided not to integrate. There are few pointers why. First, it will make the already expensive device even more expensive. 2. it will make it bigger and 3. there are 8 wires comming out and pre-charge wil bump it up to 12.
After all it is fancy ignition switch and I have not seen ignition with pre-charge yet. I will think about developing separate pre-chatge device as an addition to my eScan switch.

Click to expand...

It's like 3-4 components added to make your device useful for larger EVs rather than just ebikes. This isn't a design challenge, this is really just a tiny FET and inductor and perhaps a cap to stabilize the bus voltage. Drive the FET from a little gate driver IC driven by the uC. Then it's just some simple code.