Looking back at the schematic of the relay board there is a current limitter on the base of the transistor, this protects the cpu from high currents on IO pins. However there is no current limit on the relay side of the transistor ( current path is through emitter and collector). So the only resistance you get is the relay coil ( I measured this at ~26ohm ) which at 3v3 you get ~125mA. If you are using typical USB as your power source you get 5v@ 500mA or 2.5W. So if you are using 2 of these boards (3v3@ 125mA = 400mW) thats 3.2W.
So my conclusion here is you absolutely must not use a single USB to run 2 of the relay boards or at about 5 or 6 relays the system will brown out. You can use a double USB tap or a wall wart into the barrel jack.
You are all welcome to check my math.
Happy Easter for those that celebrate it!
@ soldermonkey: i used a 12V 4A Adapter and it reboots when it gets to relay 4 of the second board, meaning as soon as all 8 relays are on.
@ Gus,
I do not have an LED7R.
So i tested the pins on all sockets (NOT Fun at all). so i have a short on Socket 7 Type E… i tried to look at the schematics to give you the numbers but i can’t figure out which one is number 1… anyway i hope the attached picture is clear enough.
All RED Lines show the shorts i have between pins.
Is a special socket for Etherent 11J. So that is not a short.
But we tried to use 2 Relay modules with FEZ Spider and they do cause the system to reset.when all 8 Relays go on.
We will check with SeeedStudio to check the hardware design of the Relay module. Maybe the relay is causing a surge on the 3.3 power line and this causes the protection chip on EMX module to reset the processor.
So we confirm that using more than one Relay module (hardware version1.0 and version1.1) does not work.
I am struggling with the relay board issue as well. I have some deployed product that is rebooting and my solution going forward is to use a single relay module. That said, what do you think the timeline will be for identifying the specific issue? My product in the field would be a lot easier to fix if I had a relay board that was not defective rather than having to rewire for a single relay board.
Also, how confident are we that a single board will run OK long term or is it likely a future issue could arise from this? I am hearing its ok from the previous posts, but just wanted to get a little more comfort. Lets assume limited use of other modules connected to a spider with a 12V 5A power supply.
We forwarded the issue to SeeedStudio to investigate the issue and check if they can enhance the design. They confirmed thatconnecting more tha one Relay module resets the system but they did not provide more details. We will keep you guys updated.
I have a single relay module running 4 LED banks and am powering the spider and relays with a 9 volt battery. I can run the LED circuits for as long as the battery will last when I just power the bread board directly off the battery but when I run the program and try to control them using the relay module the spider reboots continuously.
Isn’t the point of this module to be able to control high voltage/amperage circuits without overloading the spider???
I’ve got my prototype fully mocked up and ready to have 3d plastic housings printed so I need to know quickly if this problem can be solved, otherwise I’ve got a sweet paper weight featuring several other spider modules! :}
Yes, one 9v battery jumped to a mini bread board. Jumping power from mini bread board to spider DP module and to the 4 NO ports on the Seeed relay module. From there the power goes out the 4 COM ports to 4 individual rails on a larger bread board powering 4 legs of 10 LEDs each wired in parallel.
With all circuits in parallel voltage should remain constant to all consumers (including the DP module) and amperage should be the variable and that is regulated with the proper resistors on each leg of LEDs and, I presume, by the DP module itself.
It behaves the same with all power comming for the 9v battery and with the 9v battery and USB connected to my laptop. It also behaves the same when I just power the main board with the USB connector and turn off power to the relay ports comming from the 9v battery. Meaning that if I run the program just using power from the USB to power the spider and have no power going into or out of the relay module (LED legs are not powered but LEDs for each relay on the module come on) after 5-10 seconds it reboots and continues rebooting.
I did a test just running 1 relay leg and it works fine with no rebooting. BUT, if I try to run the 3 or 4 relays I need at the same time it actually delays the reboot for about 5-10 seconds when cold and then goes into a constant reboot cycle.
I think it has something to do with the power required to keep 3-4 relays on constantly generates too much heat on the main board rather than too much current? Maybe the current going through the spider to the relay module is safe but the heat it generates on the main board is out of spec and signals a reboot?
I think it’s possible you’re drawing enough current from the 9V battery that the voltage is sagging below what the Spider needs. That doesn’t explain the heat, but it would explain the reboots.
Check the voltage across the battery terminals as you turn LEDs on. My guess is you’ll see it drop to surprisingly low levels.
Is this “9v battery” you talk about like you have as a backup battery for your clock radio or smoke alarm? ie is it a PP3 or 6LR61 type? If so then they have virtually no current draw capacity, they’re quite limited. You draw too much from them and their voltage drop is huge. I too agree with Godefroi, you’re getting brown-outs and that’s causing all sorts of issues. Pick a different power source.
Hi Jay,
LOL this sounds like it’s a curse laid on all those named Jay ;D
on Serious Note, STOP using the relay from SeeedStudio before you burn your Spider and regret it… As JOE confirm, there is an Issue with the relay board and it’s best if you wait for a fix or replacement.
Please contact Seeed and let them know about your issue.
LOL yes, I guess we have a cloud following us around! The 9v battery is the issue because I have it powering everything, reason being that for my project I need very low voltage on my LED legs so that they have a dim glow rather than intense light projection. When I hook up a fresh 9v battery and run everything only using that power source I can watch the voltage drop by .01 almost every second and once it dips down to about 6.8 the reboots begin. The DP module needs 7 volts to opperate so that’s the issue with that.
I’m going to visit the RC/hobby shop tomorrow to get a 9.6v pack that should feed the current needed to lengthen the voltage drop duration. These packs can come rated anywhere from 1000 to 2000ma per hour vs the 250mah of the 9v battery. As long as it can keep running all my components for around an hour that will do.
I have a work around at least for my project using the relay module. It’s simply using the NC ports rather than the NO ports for the two LED legs that will need to be on (normally closed) any time the device is in use. Only 1 of the other 2 legs will need to be on at a time so by having the first 2 powered by the NC ports and only 1 of the next two controlled by the NO ports at a time I will only have power being sent to 1 relay on the module at any give time.
Thanks for all the responses and I’ll let you guys know if the 9.6v pack works or if I had to call the fire department.
I’ve got 680 ohm resistors on each leg. I have run all 4 legs separate from the spider for 30 minutes and not even seen a .01 voltage drop on the battery. It’s only when I power both the LEDs and dp module/spider moduels that I get a 9v battery to drop below 8v almost instantly and reduce by .01 nearly every second until it reboots somewhere between 6v and 6.8v.
It’s gotta be this 9v battery and it’s 250mah falling way short of the 800mah the spider is rated to consume.
Success! I bought a 9.9v pack rated at 2100mah, main use is for RC aircraft. Charged up from dead to full in less than 3 hours and running my entire set up of spider modules and LED legs it should hold 9v for several hours based on some initial discharge tests. Only about .01v drop every 2.5 minutes.
We got off subject from this original thread but if anyone needs a good mobile and quickly rechargeable power source for the spider the Life G3 Series battery pack by Hyperion is a good way to go. It is pretty easy to splice the barrel jack for the DP module into the leads of the battery pack and it even has a separate wiring connector and adaptor for use with almost any charger designed for RC style battery packs.
Only one thing to watch: the battery will not necessarily drop voltage linearly. Different chemistries (say, LiPo vs NiCd) have different curves. In general, they will drop off slowly at first, and then very rapidly near the end.
… Just remember, LiPo packs used in RC equipment are not your “consumer friendly” battery, and require balanced charging and appropriate safety measures during charging, as well as some protection from damage during use. There are many people who have published videos of said packs causing them to perform a “fire dance” when they go off. Read the suppliers instructions and heed them well !
Agree with Brett. Use the correct charger for the pack, and you’ll be just fine. Simply connecting it to a power supply in an attempt to charge it could be, as he said, interesting
i’m happy because at least i know it’s not just me… what a relief.