MSP432 Latching relay trouble

[Tkelly278 0]

Hi everyone, this is my first post. I'm really happy this community is here. I've been into MSP gear for about 2 years now and it has been a lot of fun. I have only been making simple projects but I've learned much and had a ton of fun.

The latching relays below work with a MSP430 board, but not a MSP432.

V23042- C2108 - B101

http://www.jameco.com/Jameco/Products/ProdDS/2133528.pdf

Using standard Blink code in Energia pins 9 &10, 11&12, and a few others were used. Individually pins can sink to activate using 3.3V source on board and also source to activate when using ground on board. Between two pins the voltage alternates between 1.6V and -1.6V. Across a 1k resistor voltage alternates between 3.3V and -3.3V, same as when the leads are open.

The resistance across the relay coil is 85Ohms.

If this relay does not work with the 432 is there one that will? Are there solid state relays that can replace this?

Please help me make this the best Halloween ever.

[terjeio 134]

I would never drive an inductive load directly from a MCU pin. Desigining a driver circuit for the relay in question will require at least four transistors as you have to reverse the coil current for switching the relay off. An easier option is to use the dual coil version and two MOSFET transistors (eg. 2N7000) for switching, I would also add a diodes to shunt back EMF even if the transistors has one internally. A solid state relay or even a MOSFET may also be used, but then you did not specify what kind of load you will be switching...

[Tkelly278 0]

Thanks for the help. The load will be 110V and up to 2A, maybe 3A. By the time enough transistors were set up to run it properly i'd be better off getting a non-latching version.

I want to use the multiple processes and OS of the 432 to make all the lights in my house blink separately so it will look possessed.

[enl 227]

For your application, I'd definitely agree to go with non-latching. Latching relays are the cats meow for cases where the time between switching is relatively long and persistent  state is needed without power, such as power fail tolerance or very low power battery operations. This is why they are seen in thermostats, where low power is key, but not in motor controls, where you want it to drop to the off state on power loss, so the motor doesn't start right up when power is restored.

[Fmilburn 446]

@@Tkelly278

 

Please be careful with that level voltage and currents if you are not sure of your abilities.  A safe and easy to use, although somewhat expensive solution, would be something like this.

[Tkelly278 0]

Thank you again for the input.

Power wise I'm pretty OK with all of this. I used the relays in question with a 430 over the summer for a swamp cooler project running a water pump and a fan all at 110V. AC power is dangerous, and I have been lit up once when taking out a hot water heater. Thankfully I survived and treat wall power with the respect it deserves.

I'm going to order the proper relays and use some small op amps and diodes I have to trigger them. Thanks for all your help. Hopefully they show up in time to light my house up for halloween!