TSDZ2 speed sensor works partly

[Alexey]

I already wrote about it here, https://www.pedelecs.co.uk/forum/threads/tsdz2-250w-vlcd5-speed-sensor-strange-behavior.41280/#post-618132, and the problem still persists.
Maybe, if I write it in another words, I find somebody with the similar issue.
The issue is my VLCD5 shows the current speed correctly only when brakes are pressed. The brakes are from the kit, they are connected to VLCD5. Release the brake -> the shown speed freezes.

The wires might not be connected correctly, the signals also might be mixed up in the wires of installed head/tail light (https://www.aliexpress.com/item/32948574121.html). But if I understand correctly, the speed sensor is a quite simple device with only two wires that matter.

- Here's the demo.

This might not seem to be a big issue, but it's quite inconvenient. The screen is useless because without the correct speed data, the shown battery level is not correct as well as ODO/distance.

 

[vfr400]

You have the wires in the connector out of sequence in one of the connectors. The brakes are a simple switch to ground, but if they have three wires, then they have an addditional 5v to power the switch.. Normally, all parts supplied with kits are in the correct sequences, but if you buy anything separately, there's a fair chanc that they won't be.

 

[vidtek]

Diagnosis: Start by eliminating all unnecessary connectors. Remove the additional connector for the mini switch. Remove both the connectors to the brakes.
Check the instructions for the speed sensor input with the corresponding cable from the speed sensor itself, make sure it's plugged into the right socket.

Then add the other plugs one by one until the fault occurs.

There you have the problem. Logical sequence.
Mine works correctly, but I have removed the extra switches, not really needed at all.

Cheers Tony.

 

[Alexey]

The issue might be related to brakes with sensors. The behavior is quite strange.
If I disconnect any one of the brakes (or both brakes), the speed sensor starts working.
But at the same time, the engine itself stops working - no power assist.

So I can either use the engine or have the correct speed shown.

What I investigated for now:
- There're 2 brake levers, each has a connector with 2 contacts. These contacts are connected when brake is not pressed (1Ω) and disconnected when brake is pressed.
- Brakes are probably connected as a serial circuit - an engine works only when both brakes are not pressed that means when there're no resistance in the circuit.
- For some reason the connection in brakes prevents speed sensor from showing the data.

I thought that the brakes with sensors is an optional part of the kit. But for me an engine does not work without them. vidtek, do you have brake sensors connected or not?

 

[peter.c]

Under the display which plugs have you used ? should be outer 2 for brakes middle for throttle if fitted

 

[Alexey]

Yes, I used the left-most and the right-most. But also tried center and left - this case the signal from brakes does not go, the speed sensor works, the engine does not work.

 

[KeithMac]

My TSDZ2 worked straight out of the box, just the VLCD5 display, motor unit, battery and speed sensor fitted.

Is it all standard wiring?.

 

[Alexey]

My TSDZ2 worked straight out of the box, just the VLCD5 display, motor unit, battery and speed sensor fitted.

Is it all standard wiring?.

In my case the brake sensor (the circuit from one to another contact of brake sensor connection) is connected when brake is not pressed and disconnected when brake is pressed.
Obviously, the only purpose of the brake sensor is to disable engine when brake is pressed.
Brake pressed <=> circuit disconnected.
If remove the brake sensors (disconnect brakes) => circuit disconnected => the system counts it as the case when brakes are pressed and disables the engine.

Hence, TSDZ2+VLCD5 kit does not to work without brake sensors. At least, my version does not work.

 

[vidtek]

The issue might be related to brakes with sensors. The behavior is quite strange.
If I disconnect any one of the brakes (or both brakes), the speed sensor starts working.
But at the same time, the engine itself stops working - no power assist.

So I can either use the engine or have the correct speed shown.

What I investigated for now:
- There're 2 brake levers, each has a connector with 2 contacts. These contacts are connected when brake is not pressed (1Ω) and disconnected when brake is pressed.
- Brakes are probably connected as a serial circuit - an engine works only when both brakes are not pressed that means when there're no resistance in the circuit.
- For some reason the connection in brakes prevents speed sensor from showing the data.

I thought that the brakes with sensors is an optional part of the kit. But for me an engine does not work without them. vidtek, do you have brake sensors connected or not?

@Alexey , Logically what you are saying is the brake sensors are a short-circuit design and are required to be connected in circuit in order for the motor to operate. When they are open circuit the motor can no longer operate. It seems a bit arse about face to the normal way of doing things. If there are no brakes connected or a kit with no brakes is supplied then there would need to be a shorting plug on the sockets of the display unit for the motor to function. I'm pretty sure this is not the case.

I will disconnect mine and see what is what. I'll get back to you at the latest tomorrow.

Cheers Tony.

 

[vfr400]

In my case the brake sensor (the circuit from one to another contact of brake sensor connection) is connected when brake is not pressed and disconnected when brake is pressed.
Obviously, the only purpose of the brake sensor is to disable engine when brake is pressed.
Brake pressed <=> circuit disconnected.
If remove the brake sensors (disconnect brakes) => circuit disconnected => the system counts it as the case when brakes are pressed and disables the engine.

Hence, TSDZ2+VLCD5 kit does not to work without brake sensors. At least, my version does not work.

It doesn't work like that. The system is controlled by a cpu, which has a series of inputs and outputs. It works at 5v, like most cpus and other digital devices. The cpu is checking the pin that the brakeswitches are connected in parallel to. That pin gets a feed from a normal 5v through a high value resistor, so it's floating high. The brake switch has one wire that's grounded and the other (signal wire) to the pin on the cpu. When you operate the brake, the signal wire and hence the cpu pin is grounded, so the cpu sees low.

That's it. When the cpu sees high, it gives power. When it sees low, it cuts it.

 

[KeithMac]

I'd say vfr400's description is right and that's why mine works out of the box. I have unused sockets on the VLCD5 holder.

 

[vidtek]

@Alexey - There is no 5v on the brake sensor cable. It is purely a ground on/off. The way mine works is when the cable is totally disconnected the motor will work so it has to be an open circuit=motor on, short-circuit=motor off.

That is the way it works on my unit. As @vfr400 says it probably just pulls a port on a logic device down to ground, so disconnecting the motor.

I would say from what you are telling us you have a faulty head unit.

 

[Bikes4two]

Just tidying up this post in that the OP's issue is still resolved as at 18Jul22 as mentioned in this post HERE.

 

[Alexey]

A year later: the engine was dismounted, and an old plastic blue gear was replaced. It was convenient to update the control unit at once (just €45, https://www.aliexpress.com/item/1005004586875464.html). And then the magic happened: I got exactly the same issue - speed is shown/changes only while the brakes are pressed.

 

[Woosh]

the fault may be in the cable between your controller and the LCD.

 

[jayx]

I think it's unlikely to be the cable between controller and LCD, I suspect there is some sort of digital line between these, like RS232 or SPI so it would be more than just the speed reading affected.

Anyway, recently I've had problems with speed sensor (no speed reading) and was surprised that there is no information (at least I couldn't find anything) about which pin of the connector is actually speed sensor signal. I had to x-ray the connector to find out . So I thought I'll post it here, it may be usefull for someone.



In my case the sensor was "Hall" type, which means it required power supply (5V). Perhaps there are "reed switch" type sensors which only require GND.

To test "Hall" type sensor, connect it to power supply and connect multimeter between 5V and Speed sensor signal. Multimeter should read ~0.8V if the mgnet is away, and ~5V if the magnet is close to the sensor.

To test controller and its cable, first measure voltage between GND and 5V pins. If it's OK, then measure voltage between GND and Speed sensor pin, it should read ~5V. If all looks good, use a resistor (I've tried 1kohm, but anything between 1-100kohm should be fine), connect one end to GND and touch speed sensor pin with the other end of the resistor a few times, there should be some speed reading on the display.

In my case the problem was poor connection on one of the pin. I've bent them slightly and it started to work.