Exercise Bike Computer.....PIC Ideas

[rayyolanda]

Hi All,
I have an exercise bike that the computer died on (too expensive to replace).
I can identify an ADC TLC548CP and an EEPROM 93LC66B on the board along with the CPU / Controller (Unknown type etc). I need to make a replacement controller.

Resistance is controlled by a DC motor pulling a magnetic brake which has a 5K pot as a feedback / position sensor. I looks like the ADC is used to adjust the motor position.
Speed / Distance is just a Reed Switch and magnet, one pulse per revolution.
Heart rate monitor is done by a small board, not sure of how this hooks into the main controller yet.

So my problem.......I have some 24HJ128GP502 and 24FJ64GA102 (seems to have an Int Xtal for RTCC) and a dsPIC33FJ128GP802. I am looking for some comments about using these chips...I have only played with 16 and 18 series and never touched RTCC with PIC. I want to write in C code, so are there any recommendations about a compiler? Not sure about display...LEDs and some 7Seg or a GLCD (which controller is best?)...would like some comments on this.

I will need......
- RTCC for timing of programs
- Place to store programs...on chip....eeprom
- ADC for the motor position
- DC motor drive....H Switch.....?
- Capture Compare Module for revolution count..speed / distance
- possibly another Capture Compare Module for the Heart Rate
- Display.....7 Seg or Character LCD or Graphic LCD

Any ideas....comments......?

Thanks everyone.......Ray

 

[joed]

Excercise bike

Ray,

Is your bike a Universal Fitness model?

Thanks
Joed

 

[rayyolanda]

Hi Joed,

Sorry to take so long to reply. No it is not a Universal Fitness model.It is a V-Max MPE Fitness Bike. These machines are all very similar from what I have seen so if you have any info on this type of bike...please let me know.

Basically it uses a motor to pull a magnet toward a magnetic wheel to provide resistance.

Thanks

Ray

 

[joed]

Universal Recumbent Excercise Bike Controller

Ray,

Thanks for the update. I was able to get at the internal mother board and checked as many of the components I could with the exception of a few IC's. I did replace an
EEPROM that was on a socket but this did not help. I get a beep and a brief light of the read out panel then it continues over and over. Apparently an electronic component must be defective. I have to get a bike pedal crank puller to remove the pedal arms to get access to the magnetic drive and motor. I plan to make a controller for the resistance only and use it that way, bypassing the on board computer controller.

There is absolutely no information about this bike. There is no model number only a long serial number that I cannot cross reference it to. I call Nautilus who bought Universal and they have no information on this bike and nothing on the internet. If I could bet a hold of a schematic for a basic configuration for magnetic resistance bikes, it may help.

Thanks again,
Joed

 

[rayyolanda]

Hi Joed,

Look carefully at the cranks when getting a gear puller....there is not much room for the puller and don't get a 2 arm, get a 3 arm puller. I gave up on pulling the cranks and basically forced the trim panel over the crank arm....a small crack ....but will never be noticed.

I have not seen a schematic but I came across a site selling parts which you can see from the pictures are the same. Your computer sounds the same as mine. From what I could see the computer / controller drives the resistance motor which also has a resistive pot. The pot is checked by an ADC chip (on my controller) and this I assume is relayed back to the program. The motor is driven by a simple H Switch using transistors. The Eeprom I think will be the settings for programs and person settings.

If you are using PICs then maybe we can collaborate on the project. There are other item such as heart rate monitor and some additional program options which may or may not be implemented. I have not been able to spend any time on this project but hope to return to it very soon.

Ray

 

[joed]

Universal Recumbent Excercise Bike Controller

Ray,

Thanks for the heads up on the crank puller. I did not know that. I called a local bike shop and they have a crank puller for what they called square tapered end, looks like a ratchet wrench around $15. I would rather get the pedals and arms off rather than cut the side panels. The Universal bike has large heavy plastic side panels.

Regards,
Joed

 

[rayyolanda]

Hi Joed,
Your problem may be a permanent reset on the controller chip......a faulty Cap.?
Did you look with an oscilloscope at all? Mine was dead.....
Good luck with the puller.
Here is some info I gathered...it may be useful for you..wire connections.

White------NC
Gray-------+V
Purple------GND
Blue--------GND for Rotation Sensor
Green------Rotation Sensor
Yellow------Motor POT end 5K pot
Orange-----Motor POT mid / wiper
Red--------Motor POT end
Brown------Motor 5volt...maybe 6volt
Black-------Motor 5volt...maybe 6volt

A PIC will be able to handle all this. Do you use PIC?

Ray

 

[joed]

Universal Recumbent Excercise Bike Controller

Ray,

What is a PIC?

I have a volt ohm meter no scope. I have not purchased the crank puller yet. Are there electronic components at the bottom section of the machine where the magnetic resistance devices are and the sensors?

I would like to connect a simple switch or potentiometer at the end of the ribbon cable that goes into the top controller and operate the resistance motor part only so I can use the machine manually. I don't need all the features that the controller provided.

There are dc voltages 9 volt and below on certain pins. I have not made a diagram yet of the pin outs. But they are different than yours. At first I was thinking of placing voltages from pins to other pins to see if the resistance mechanism responded. But I don't want to damage any components that I cannot see at the end of the ribbon cable.

So I really don't know for sure if the problem is the top controller or some component at the motor end of the machine or a combination of problems.

I replaced the EEPROM that was in an IC socket. I get a beep, then display that shows all the possible functions that goes out, the #78 for RPM that goes away the letter "E" for error, then the word in large letters scrolls horizontally across the screen that says, "TITANIUM" that goes out then the cycle begins again.

Nothing on the internet for Universal Fitness Titanium Exercise Bike or other search options.

I checked for patents to see if there were any diagrams and I found something but I don't know if it applies to my machine or not.

Thanks,
Joed

 

[rayyolanda]

Hi Joed,

A PIC is a Microcontroller. Don't start putting volts on wires if you don't know what they are for.....this could lead to disaster.

From what you say it looks like your controller is working. It is giving an Error code 78. What that is we don't know. However, and I generalize here......most of these machines seem to to 2 things when you apply power....1 Start the code running ......2 Check for errors condition by reseting or moving the motors and sensors. So it would seem that you have (this is a guess) a faulty motor...or potentiometer on the motor....or maybe a sensor, heartbeat or revolution but I doubt this last one is very likely.

I would check the resistance of the pot with your meter if ok then check that the motor is not open circuit. This could be a wiring problem...open or short circuit. The motor is most likely a DC 6v type....so if you connect 6v it will run....reverse the connections and it will run the other way....remember that the motor is not designed to run for more than a few seconds.

I think it is a motor problem or the pot.....the machine tries to reset the motor (resistance setting) when it powers up....I think that this is where the error is posted.

Good luck...let me know what happens.

Ray

 

[joed]

Universal Recumbent Excercise Bike Controller

Ray,

Thanks very much for the information. I located the +9vdc from the ac/dc adapter on the pins to the controller. If I disconnect the connector and place +9vdc on the same pins to the controller I get the same results with the error 78 etc. If I reconnect the controller to the connector with voltage from the adapter source, I get the same results. If I use another adapter same voltage, same results.

You make a good point, it could be because the controller is not seeing the motor and or sensors. At first I thought it was something with the controller since when disconnected I am getting the same results.

This trouble happened after the temperature dropped in the low 30's. That is cold for Central Florida but I would think it would not be too cold to cause a fault, not sure.

I must get the crank puller and look inside where the motor and sensors are.

Thanks again,
Joed

 

[rayyolanda]

Hi Joed,
Cold can cause Dry Joints to play up.......
Ray

 

[joed]

Universal Recumbent Excercise Bike Controller

Ray,

I got a crank puller, $16.00 opened the bottom sides and took note of what's what.
I was able to power the motor from the pins off the dc supply. The motor is good. I tested the potentiometer, it appeared to change resistance when the motor operated the cam and magnet.

I did everything I knew how to find the problem. I notice the speed sensor mounted on the frame and the small magnet on the fly wheel. I tested it and it works fine. There are 2 wires going into the gear case where the potentiometer
is and the wires read open.

I ran the motor and still see an open. I have no idea what the wires go to. I measured for voltage on the pins to these wires bridging off the mini connector, reads zero. I bridged a short across the pins to these wires and powered up the unit and no change still get the beeping and error and LED flashing.

I did notice at one point when I ran the motor then connected the mini connector to the controller, that the controller appeared to display properly. I was able to navagate
to manual and change the resistance on the LED but the motor would not run.

Then I ran the motor with my bypass set up and reconnected to the controller but I could not get the LED to display properly again. I have a feeling either the device that the 2 wires I mentioned is bad or the controller is bad.

If I knew what the device is maybe I could do something. The wires go into the plastic gear box. I could take it apart and look but I am concerned that gears may come loose and make matters worse. So, I got a DPDT momentary on with spring to center off switch and wired it to the motor and DC power.

I mounted it on a plastic plate that substitutes for the original controller and now I can increase or decrease the resistance with the switch. This makes the unit semi automatic. Do you have any clue as to what component, either the controller or the unknown device in the gear case is bad?

I think the potentiometer is working because it changes resistance when I run the motor but I really didn't plot the resistance readings as the motor ran. I noticed it went from a high reading not sure what it was at the time to a short. What is the POT for?

Thanks,
Joed

 

[rayyolanda]

Hi Joed,
The Pot. It changes resistance for motor position and this is converted by an ADC to give a digital number to the controller. The ADC may be part of the controller IC or separate IC as is my case.

The 2 wires. Could be a limit switch which is checked on power up when the motor runs. Or could be nothing...for a different model. Try to trace the wires back to the controller. Check if they are power or ground.

Ray

 

[fauxxpas]

Universal bike help..

Hi~ I realize that this forum is for electronics, but it also looks like the posters on this thread may be the only people online that may know what my problem may be.
I have an older Universal recumbent bike. I have no manual and the resistance seems to have stopped working (re: uphill, etc.).
It worked well the first few times I used it.. Does anyone know of anything very basic that I might check?

thanks, and pardon any intrusion...
Kathy