I recently was informed of another Honey Stick Machine it is on the market. It is not automatic, but sounds like it may work a bit faster than how I’ve currently been filling straws. It consists of a special pump that is made special in india that fills the straws with raw, unheated honey and special trasy that hold 14 straws for sealing. The gentleman selling them says that with two people he can fill and seal 1000 straws per hour.

The machine costs $1000 and is available from Dunbar Honey Farm, Jerry Dunbar, 586-770-9953. I do not know if that price includes the sealer or not (I’m assuming he uses an impulse sealer as I do). If anyone gets to see this machine or has one, please let me know what you think of it.

Update: The gentleman who is offering this machin says he knows the the person who purchased the Patent for the Sticky Machine and that that it isn’t being produced yet because he has been unable to get the design to work. This seems to confirm the rumors I’ve heard elsewhere. Dissapointing as I would have loved to save all the time and money of designing my own. I had some hope that the Sticky Machine would soon be on the market again as I have know some people who have seen the Sticky Machine’s Inventer with a working version of the machine, but it appears it won’t be any time soon.

I’ve already covered the outputs required from the Phidgets Controller in previous articles. But you can’t forget the inputs. While the Honey Stick machine could be setup to simply run on timings when to do what, and assume that each task is done correctly, it would be prone to problems if anything varried. Even differences in the thickness or temperature of the honey would cause problems. Thus I intend to include quite a few input sensors to make the machine smart enough to adapt to most situations. These inputs will include:

1. Temperature of the straw sealing heating elements. Temperature when melting the plastic ends is critical to getting a good seal. Too low a temperature won’t seal the straw, and too high will melt though and leave a hole. While this could be controlled by a simple thermostat, it’s easier to adjust on the fly if the computer knows what the temperature is. Plus, sine the Phidget’s USB interface has plenty of inputs, it costs a fraction of the amount that a dedicated controller would cost.
2. Temperature of the honey. My honey stick machine will include a heater for the honey (or other syrup) to keep it flowing well. We don’t want to overheat or even pasterize the honey (my customers perfer raw honey), but it flows much better at 90 degrees than at room temperature (which may only be in the 60s at my house in the winter). It may also give the computer an idea of how fast the honey should be flowing so as to adjust timing of filling cycle.
3. IR Emitter and Detector pairs. These will basically function like the safey eye on your garage door. When the beam is broken, something is in the way. In this case it will either be a straw or honey. We will have 4 such pairs to determin if there are straw in the bin, in the filler holder, if there is honey in the feed line (or if we have run out of honey), and if the honey has filled the straw. I expect the positioning of this last sensor to be critical to get repeatability without having to clean the heating elements constantly. Too much honey in the straw and the honey will leak out everywhere, too little and it will leave air bubles and burn though the straw. (Less time/heat is required to seal an empty straw vs. a straw with honey at the sealing location)
4. Current Sensor to determine if the pump is running. This wouldn’t seem necessary as the computer is telling the pump when to turn on, but the pump we have chosen has overrides that may cause it to turn off without the computers knowlege. Thus I think it would be usefull to have this additional input. It may prove to be unnecessary in actual use (the pump may never turn off on it’s own), but I will include this circuit in the prototype.

That pretty much fills up all 8 of the Phidgets analog inputs, and fortunately I can’t think of anything else I need to monitor at this point. I will take advantage of several of the Phidget’s digital inputs as well to add features like a ‘kill switch’, power switch, start button, etc. so that it could basically be run without looking at the computer screen (once all the bugs get worked out). The Phidget’s also has 8 of these digital on/off inputs, more than I can think of a use for right now.

Status Update: I have ordered and received most of the electronics parts that I think I’ll need. I’ll begin wireing and testing circuits possibly later this week if time allows. I do plan on building them in modules and not just one big circuit so that it will be relatively easy to adjust for the final machine.

One other problem using the Phidgets USB interface is that it simply doesn’t not have enough outputs to control all the devices I want to control. We could simply use a second USB interface, but in the interest of minimizing cost I’m trying a different method. Instead I will use the following circuit to control 8 devices using only 4 outputs of the USB interface. It is a relatively simple circuit that can be built with 6 off the shelf 7400 series TTL ICs. It also could easily be expanded so that 5 USB interface outputs control 16 separate devices. (and theoretically up to 128 devices using all 8 outputs of the USB interface) The D-type flip flops are positive edge devices.

One Input to this circuit determines what state the selected output should be in, and the 3 selector inputs determine which of the outputs should be set. In operation the state should be selected first, then the selector inputs should be sent. One significant outstanding issue is if the outputs from the USB interface change simultaneously or not. If they do not then the circuit may inadvertantly change the state of other outputs on the way to changing the desired out. If this turns out to be the case then an input latch and delay will be required to ensure the inputs arrive at the same time. I won’t be able to determine which case is true until I can breadboard and test the circuit.
Another inherent limitation of this circuit is that the 8 outputs can only be changed one at a time and could effect timeing. In most cases this isn’t a problem, but for the solenoids and other devices that need to be more responsive I’ll use one of the remaining 4 outputs of the USB interface.

I should note, that after working out the above, I ran into the specs for the 74LS259 8-bit addressable latch and it appears that it could replace the entire circuit above. It may however suffer from the same problem as the above cicuit and may require the inputs be latched and timed so the output is as expected.

Making honey sticks (or maple syrup) sticks is a straitforward and simple process. The basic steps involve filling a straw with honey and then sealing both ends. The difficulty arises in actually getting the honey into the straw and doing it efficently (so that the time it takes to make them isn’t more than the value of the honey stick itself).

Initally to see if they could be simply made, a sort of proof of concept, and so that we could make some as samples we used a large plastic syringe (pictured to the right) from US Plastics. The tip did need modified slightly to fit inside a standard drinking straw (available from any resturaunt supply store). The tip can be molded by heating it and molding it carefully with your fingers, being careful not to burn yourself. It does work reasonably well if the honey is warm, though is not really suitable for making large numbers because it needs to be refilled every dozen honey sticks, is relatively slow and can be quite a strain on the hand.

Sealing the ends or the straw is a simple task using an impulse sealer (left). Again these are available from US Plastics, on ebay and from many other retailers. The heat is easy to adjust with the knob on the front of the sealer. You will need to adjust it by trial and error until you get a good seal. Do not adjust it by using an empty straw. You will quickly find that it needs far less heat to seal an empty straw than a honey filled straw. (I should also note here that the impulse sealer is also very usefull for sealing plastic bags and even making pollen patties, so it is usefull for more than just making honey sticks.)

Making honey sticks in larger numbers requires a better setup for filling the honey sticks however. Instead of using a heated honey tank, hand pump and manifold that holds several straws, we have used a simple stainless steel pressure tank. This tank (right) is a surplus tank originally used for holding premixed soda (or pop). Mine was purchased on ebay. Honey is placed in the tank and an air compressor is attached to pressurize the tank to 90psi. The straws are then filled using a simple valve with a brass nozzle. It does work better if the honey is warm, though I do not like heating up the honey as much as other systems do and have found this system works resonably well at 90 degrees. Before we start the tank is placed in our honey warmer, but during use it’s placed in a 5 gallon bucket with a band heater to keep it warm (sold for heating up honey buckets by Mann Lake and others).

To make it easier to fill many straws at once, a plastic or wooden bar with holes (and split down the middle) is used to hold a dozen straws at once. This makes it relatively easy to fill and seal several at a time (below). It does make a bit of a mess, hence the newspaper for easy cleanup, but does not make as near the mess as the plastic syringe. Once sealed the straws ends can be cut close to the seal and washed in warm water to make the finished product. With practice you can get to the point where many of the straws are sealed very close to the end and don’t need cut.

I am building an automated honey stick machine as it’s simply getting to take too much time when making honey sticks by the 1000. But if you are looking to make some as samples, or even several hundred at a time, the above works pretty well with considerably less expense than a commercially available system.

Some of the outputs of the Phidgets USB interface will be used to drive AC voltage. For these I’ll simply use a solid state AC/DC relay because it provides reliability and isolation from the AC line. Plus it’s much cheaper than building your own circuit unless more than an Amp or so needs switched.

The rest of the outputs will be used to drive solenoids using a MOSFET solenoid driver as pictured below. The MOSFET driver was chosen simply because I was concerned about the somewhat limited mechanical life of the relays in a transistor relay driver.

MOSFET Solenoid Driver: This is a very simple circuit and is repeated for each of the solinoid or other DC devices we wish to control with the Phidget USB interface. It accepts a digital 5 volt input and can drive a significant amount of voltage and current depending on your selection of MOSFET. I have added a LED to the circuit as well to indicate the state, after all… the most important part of a fancy machine is a lot of blinking lights.

R2 is a a 1M Ohm resistor intended to drain the voltage on the input when it goes to 0 and speeds up the switching speed (as the MOSFET gate can act as a capacitor. R1 should be sized to limit the current though the LED, with a typical LED with a 1.7 voltage drop and 20mA current rating , R1 = (V – 1.7)/ 0.02. Or 515 Ohms at 12V or 1115 Ohms at 24V, etc. (round up to the nearest resistor).

Phidgets recommends D1 be a 1N4148 diode, which is a high speed 200mA 100V diode. Due to some of the currents I will need to be switching, I’ll be using a 1Amp or better version instead.

As previously mentioned, I intend to use the Phidgets 8/8/8 USB interface and a computer to control the honey stick machine. Before I get too much into the actual mechanical design, I need to define the steps involved and all the output’s and inputs required.

First the outputs…. I intend to use solenoids for most of the moving parts of the device. They seem to be more readily available than the pnumatic cylinders used in the Sticky machine, and for me at least, I’m much more familiary with the electronics with my electrical background. Plus, with a rated life of 2,000,000 cycles they should be reliable enough. I originally intended to drive them with simple transitor driven relays, and even designed the driver circuit, but I was concerned with the mechanical rating of only 100,000 cycles on the relays. This may sound like a lot, but with a machine in the $3000 price range, if it needed replaced every 100,000 honey sticks, it would cost 3 cents per stick just for the machine cost alone, or around $132 per 5 gallon bucket of honey processed, nearly the price of just sending the honey to someone else to fill (at $175). So to minimized the cost per stick, I’ve opted to use mosfet solenoid drivers, and solid state relays for the AC devices (the pump, etc.) which should reduce the cost of operation by a factor of 10 or more.
The outputs are as follows:

1. Straw feeder, drops the next straw into the machine (solenoid)
2. Straw ejector, kicks out the filled straw from the machine (solenoid)
3. Clamp, holds the straw while in the machine (solenoid)
4. Filler nozzel, moves the filler nozzel into place (solenoid)
5. End positioner, effectively clamps the straw horizontally while filling (solenoid)
6. Right sealer (solenoid)
7. Left sealer (solenoid)
8. Honey pump (120V AC pump, AC relay)
9. optional – Honey heater (AC relay)
10. optional – right sealer heater (AC relay)
11. optional – left sealer heater (AC relay)
12. not used

Of course one should note that more than 8 outputs allowed by the USB driver are proposed. While we could do without the heater relays, it would be nice to control everything from the computer and I’m not quite sure what I’ll run into once I get into the guts of the machine so an extra output is good.

Demultiplextor and driver circuits are to follow in the next post….