Paul & Sabrina's cheap DIY 144v motor controller

[flores]

The raspberry is basically just a computer.
It's really cheap 30$ or so, has an ARM processor and runs Linux (raspbian, a debian variant) it's powered by USB (so 5v) and uses a microSD as a disk

What I do is run the mono framework on raspbian, which is an open source implementation of the microsoft .net framework.
This allows me to develop in C# and Visual Studio.

The program I wrote uses nancyfx to host some webpages that makeup the graphics.. (using the Telerik kendoui controls) and read data from the serial.

[flores]

Did that all make sense ;-)?

No more questions.. haha

[MPaulHolmes]

No, but it gave me a bunch of search terms for further reading. Haha

[Astro]

Originally Posted by jedsmd

The the new hall effect PB-6 throttle box clone has arrived from China. I have installed it on the truck and made the wiring changes to the controller board.

It came without a datasheet of any kind so I had to wire it by trial and error. If anyone else buys one of the ones off eBay the wiring for mine was:
+5v - Blue wire
Signal - Black wire
Ground - Brown wire

Measured voltages are:
Zero Throttle +0.20 volts
Throttle contactor closes +0.20 volts
Max throttle +3.95 volts

There is a small flat area at the low end before voltage starts climbing which is why 'zero throttle' and 'contactor closes' voltages are the same.

Paul
Please send me some spread spectrum code
Thanks
Jerald

My hall pot box arrived.

I found very similar results to Jerald except for the voltages.
I am assuming Jerald used +5.0v supply
I bench tested using a +4.91v supply (this was the voltage i had handy) and the pot box has
a zero throttle of +0.26v
throttle contact at +0.26v
full throttle gives +4.83v

There is a small amount of travel near zero throttle and full throttle where the voltage doesn't change. The voltage reaches maximum just a fraction before being stopped by the physical stop. Same at the bottom end, the voltage reaches minimum just before hitting the physical stop.

So the throttle arm starts at it's minimum up against the physical stop giving +0.26v
after about 2% travel the contact clicks and the output is still +0.26v
then another 2% travel and then the voltage starts increasing from +0.26v through to +4.83
at approx 95% travel the voltage reaches +4.83v
voltage then stays at +4.83v right up to 100% travel where the throttle arm is stopped by the physical stop.

This sounds correct to me.

[jedsmd]

Originally Posted by Astro

My hall pot box arrived.

I found very similar results to Jerald except for the voltages.
I am assuming Jerald used +5.0v supply
I bench tested using a +4.91v supply (this was the voltage i had handy) and the pot box has
a zero throttle of +0.26v
throttle contact at +0.26v
full throttle gives +4.83v

There is a small amount of travel near zero throttle and full throttle where the voltage doesn't change. The voltage reaches maximum just a fraction before being stopped by the physical stop. Same at the bottom end, the voltage reaches minimum just before hitting the physical stop.

So the throttle arm starts at it's minimum up against the physical stop giving +0.26v
after about 2% travel the contact clicks and the output is still +0.26v
then another 2% travel and then the voltage starts increasing from +0.26v through to +4.83
at approx 95% travel the voltage reaches +4.83v
voltage then stays at +4.83v right up to 100% travel where the throttle arm is stopped by the physical stop.

This sounds correct to me.

On the bench I was getting about 4.8v as the max throttle. But in the truck max throttle is 3.85v. I've been scratching my head.

My best guess is that being bolted to the firewall weakens the magnetic field.

[MPaulHolmes]

It could be the pull down resistor on the control board?

[Astro]

Originally Posted by jedsmd

On the bench I was getting about 4.8v as the max throttle. But in the truck max throttle is 3.85v. I've been scratching my head.

My best guess is that being bolted to the firewall weakens the magnetic field.

My first guess would be a low supply voltage.
Is the supply voltage still around 5v when it is in the truck?
Maybe try using an independent supply voltage to test it when it is bolted in position.

Or try taking it off the firewall but still connected to vehicle supply to see if the mounting position is the cause.

The cable allows the throttle arm to move all the way to the physical stop?

Could the wiring changes to the controller still have a series resistor in the supply circuit or something like that that allows the supply to test as 5v unconnected but when connected to the pot box it doesn't deliver full 5v?

[Astro]

@Paul You beat me too it again. I spend too much time writing a reply and then when i submit the reply i see others have already made the same suggestions.
I should learn to use the preview post to check for other replies before hitting the submit.

@Jerald If you need me to do any tests to compare results just let me know.

[MPaulHolmes]

I think they can only supply 2ma of current on the output, but the pull down resistor is sucking 1mA. Maybe the pulldown should be more like 47k instead of 4.7k.

[Astro]

Originally Posted by MPaulHolmes

I think they can only supply 2ma of current on the output, but the pull down resistor is sucking 1mA. Maybe the pulldown should be more like 47k instead of 4.7k.

I'm at work at the moment but in a few hours i can check and see how much current the device uses.