simple timer

Community Projects
1

Hi Forum,

have purchased this el-cheapo fog machine for halloween - it comes with a remote RF activator which when pressed fires out the fog…

the challenge is i can’t seem to find a timer for this (as i want to leave it unattended and release fog for let say 3 seconds every 30 seconds, or something like that)

is there any off the shelf module which may work- as this gets used once a year - i was thinking if a simple module which shorts the press switch on the remote (like pressing) as a work around

any ideas- I don’t really want to invest a huge amount into this so a good enough for the night works

2

An Arduino with a relay module would work. Modify the blinking LED example.

3

I have a post with some code [here.](http://www.cedarlakeinstruments.com/blog/?s=cycle+timer)

4

Lyndon,

based on your reply Arduino board with this code your advised.

power supply for the Arduino itself

Relay ? (not sure how much voltage Arduino supports- but i guessing for the fog machine it would be a NO -closed operation with low voltage?

if low voltage i would not need a relay to handle power - correct?

5

The Arduino can’t turn on much more than an LED or two per output. You will need a relay/relay board (yes, normally open)for anything over 20mA or so.

6

gotcha, did a check - the pins are 4VDC so relay is needed?

7

https://howtomechatronics.com/tutorials … -tutorial/

8

ok - i did a check on the fog machine - the max draw is 24.56 mA - how would i setup to Arduino Uno to accept a pin in and then pin out (et just connect them )?

9

A relay just arrived from a shop . - its 240ac 2A - this is not going to work - most of what i see is AC- are there any VDC low A relays?

10

What is the part number of your relay?

The specs will likely include the coil voltage and the contact rating.

240ac 2A is certainly not the coil, instead it is the contact rating.

11

https://hobbycomponents.com/relays/889- … tate-relay

12

this is what is looks like- local shop my bad i did say 5v single relay

13

Well, it’s a solid state relay which has a particular characteristic - in this case likely a Triac device to switch AC loads

(switching an AC voltages between 100 and 240V at up to a 2A current). Not going to work on a DC signal switching situation.

I don’t known what you’re switching on the fog machine.

14

Here, this is probably the simplest path forward: https://www.adafruit.com/product/2935

Four switched A/C outputs you can control with an Arduino.

15

The fog machine is

4VDC 25mA

But it appears I need to short 2 pins to get it to work

16

Ah. That seems like a very low current requirement.

But anyway, [this should work fine.](Amazon.com)