I need a product recommendation – I have a 2004 V70t Volvo car seat that I want to operate using an Arduino for a fun project with the kids. It has 4 DC motors (brushless I assume) – 25-30 amp operation and of course 12V. Any ideas? I also need a PSU – wall plug in preferred. I am also trying to figure out how to harness the seat memory functions – how would a car seat know? I see no rot pot or encoder attached. It could use Hall sensors – but of the two motors I had pulled so far, these only have two prong connectors.
They are probably brushed motors, not brushless (brushless would have more than 2 prongs.)
25-30 amp also sound a lot ! Is this data that you read on the motor themselves ?
The seat probably has its own micro controller, so the memory would be in that. If it is able to save multiple adjustments, there needs to be feedback. Maybe the sensors are not directly at the motor but somewhere else. For example, motor could drive the left side of the back rest and the pot may be on the right side.
I am assuming they are brushed motors too. They are Bosch manufactured (for Volvo) and I did try contacting the company for specifics with serial numbers off the jacket. They were unhelpful and not interested in providing data sheets. I am aligned with your thinking that sensors must exist and they may be on the shaft a distance away though I didn’t see them at first glance. Would you figure there should be a dedicated sensor each per motor?I a have a few leads out to mechanics for more information.
I do see that these motors for fused at 30A for the power seat module and 25A for the seat heaters. I figure moving an adult person+seat should require a decent amount of juice and hence the higher amperage. I am thinking of hacking an ATX PSU. Also, its a good chance these motor units are Hall Sensored – my lead is warmer on that. You’re right about a control module that normally comes with and drives the seat. I don’t have it though and I imagine that buying one would be formidable. Besides, could I not do it via an arduino perhaps?
In the mean time, I am looking over your provided links – thanks so much for posting! Any other insights?
Thanks for posting! What I see direct from the manual is each of the passenger and driver power seat is rated 30A. I am waiting on wiring diagram specific to the seat. From my research it is a 8-way seat but I only see 3 motors. Should there not be 4 motors then? I am also going through documentation on exploded parts diagram to find how the darn thing knows where it is – I still figure there is/are (a) hall sensors…
When it comes to seat heaters that have three settings and off-- any ideas how to do this? From wiring diagram I see a thermistor is incorporated in seat with heater. If I can get Arduino to read it, I guess I could have arduino leave heater on until a certain defined temp is reached based on a button setting and then shut off. Like a stove top element would do for low, med and high.
In any event, does Robotshop have a 30A, 3 channel DC motor breakout that I could interface with an Arduino? I look again at that earlier post with your suggestion.
If it is 8 way, there is probably at least 4 motors like you mentioned.
For the heater, this is the approach we would take as well. Read the temperature on the thermistor using the Arduino adc port and control a relay to turn the heat on/off.
We have dual 30A+ controllers but in you case we don’t think it is necessary. Because you don’t need to drive the speed (it is only move or don’t move) you should use simple relays to drive the motors on or off. ( two relays per motor for forward and reverse). It will be a lot less expensive that way. Take a look at this relay board for example. It should be enough to control 4 motors: robotshop.com/en/8-channel-5v-relay.html
That relay board would be just what I need. Only rated for 10A though-- you can see at to the 30A fuse rating. Looks like there are 4 DC motors – must be hidden in the seat back. In the centre grayed box – this must represent the switch module at the side of the chair to control by driver – any idea what the grouping of 4 switches between the top chair and three below? Also, can you figure anywhere DC motor feedback is happening?
You’re bang on about the H2 – etc as Hall sensors. I found it in some more documentation. Do you think it would be safe to assume the Hall sensors, themistor, switches, modules and memory settings most likely run at 5V? As in: I can sub in a Arduino UNO to handle all and drive that 8-Ch relay?
Honestly it is impossible for is to say. But car electronics usually work at 12V
The Arduino can control the relay but we have not idea about the sensors because the voltages levels are unknown.
Simple on-off switch done by the relays. Just make sure you cannot command forward and backward at the same time on one motor because you will cause a short circuit.
Would that be two relays then per DC motor – as in, one relay controls forward & the other controls backward then?
I may have an answer to the question of the voltage for circuitry in some of the documentation. I’ll see if I can post. There are tables linking connectors as numbered and listed on the wiring diagram. I’d like to post an example for you to look at and see if you can figure voltage.
For example, here is the tabular list of the “E” connectors from the wiring diagram seen in this topic. This contains the Hall sensors – you were right. Looking at #E3 – not sure what U=Ubat or elsewhere U=Ulow means… Could be referring to a HIGH and LOW signal similar to reading a pin on an Arduino? What does the 7.0-9.0V refer to under the “Other” column?
You probably mean voltage. In some notations, we often see U=RI instead of V= RI for ohm’s law.
It seems to indicate that voltages between 7 and 9 V may be considered a low ( logic 0) and that V bat(12V) will be considered a high ( logic 1).
Please be aware that we are not car specialists, this is only our quick interpretation and may not be accurate. You are responsible to validate everything and we cannot be held responsible for anything related to this design.
