BeanAnimal's Bar and Grill - DIY Reef Dosing Pump

DIY Aquarium Dosing Pump

  

  

Background

My current reef system is a heavily stocked mix of soft, hard and LPS corals. In addition to the coral, there is also a Maxima clam and a rather thick coating of purple and green coraline algae. Maintaining balanced alkalinity and calcium is accompolished by dosing DIY 2-part solution. The dosing requirements have slowly but steadily increased as the aquarium has matured. I currently dose nearly 100mL of each solution every day. The goal of this project is to create system capable of accurately automating the daily dosing of the 2-part solution. 

 

Design Considerations

I spent considerable time working on several different design topologies for this project. My first choice was to build a DIY fixed displacement piston pump or DIY syringe pump type doser. It quickly became clear that a reliable design would require tooling that I do not currently have access to. My second choice was to construct a peristaltic pump based system that could be accurately controlled via a small microprocessor based circuit that could be monitored and maintained locally or via the internet. There are several dosing pump systems being marketed to the reef aquarium hobby, but none fit my needs exactly. The SpectraPure Liter Meter III comes close but is fairly expensive and still lacks an ethernet interface. The Aqua Medic pumps do not have the interface features that I desire either. I tinkered around with a repurposed Kangaroo medical feeding pump but was not happy with the size or noise and the lack of control was a deal breaker. 

I decided to base my reef dosing system around a commonly available surplus Ismatec peristaltic pump. However, I also wanted to ensure that the dosing controller could be used for other peristaltic heads and motors. As mentioned, I also decided that the pump should be available on the local computer network and/or internet for monitoring and configuration of the dosing parameters and system status. 

By designing the dosing system to be compatable with larger peristaltic (or fixed displacement) pumps, the dosing controller can also be used to schedule and maintain continuous water change systems.   

 

Hardware Selection

With my design requirements mapped out, I chose to use an Atmega microcontroller to be the heart of the system. Adding TCP/IP connectivity would be easy with one of the new WIZNET ethernet modules. After several protoypes, I settled upon the Atmega128 microprocessor for its speed, power and versatility. SparkFun Electronics offers the ET-AVR board with the hard to solder Atmega128 and supporting components already attached. It is a steal at $20. I chose a Grayhill rotary encoder and 3 line LCD to complete the interface to the outside world. The Ismatec pump head was purchased from eBay along with several larger peristaltic heads. The ET-AVR board is the base of the system but does not have enough features or interface components to meet the needs of this project. The ET-AVR board and other supporting components are attached to a DIY PCB of my design. 

 

Circuit Topology

The controller is fairly straightforward. At the heart of the circuit is an Atmel Atmega128 microcontroller. The controller is interfaced to the outside world via an all-on-one TCP/IP product from WIZNET called the WIZ810MJ. The 3.3V WIZNET module communicates with the Atmega via the SPI protocol. The controller is equipped with a 3x16 LCD display and is manipulated locally via a Grayhill optical rotary encoder. A Dallas DS1338 battery backed Real Time Clock is used to keep time. There are 3 individually controllable relay outputs that are capable of handling up to 8A AC/DC each. There are dedicated inputs for float switches and misc auxilliary sensors.  

 

Operating Parameters

The dosing controller has a real time clock that manages dosing times and intervals. The dosing window(s) can be user selected for any time or day of the week. Dosing can be done either one-shot or metered to span the entire dosing window.

For example: If the dosing regime called for 100ml of dosent a day and the dosing window was from 10:00 PM to 5:00 AM (7 hours), the dosing controller can be programmed to deliver the entire dosent volume at 10:00 PM or in intervals spaced out over the entire dosing window.indow.

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Skillset Overview

 

I have ordered the latest revision of my PCB and will

Tools and Supplies

I have ordered the latest revision of my PCB and will

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Parts List

Click here for a detailed parts list that includes pricing, distributor and manufacturer parts numbers and notes.

DESIGNATOR VALUE/DESCRIPTION PART#
D1 1N4007 Diode 1N4007-E3/54GICT-ND
D2 D3 1N4001 Diode 1N4001-E3/54GICT-ND
D4-D7 1N4148 Diode 1N4148-TPMSCT-ND
C1 C2 C4-C7 C9 C13 C14 C19 .1µF 50V Ceramic Disc 478-4276-1-ND
C3 10pF Ceramic Disc P12181-ND
C8 C12 470µF 50V Electrolytic P13134-ND
C11 C15 100µF 10V Electrolytic P13455-ND
U1 ET-AVR Stamp ETAVRSTAMP
U2 MAX3222CPN RS-232 MAX3222CPN+-ND
U3 SN74AHCT1G04DBVR Inverter 296-1112-1-ND
U4 WIZ810MJ 21.99
U5 DS1307 I2C Real Time Clock DS1307+-ND
VR1 LM1084IT-3.3-ND Regulator LM1084IT-3.3-ND
VR2 LM1084IT-5.0-ND Regulator LM1084IT-5.0-ND
K1-K3 5V SPDT 120V/16A Relay PB1038-ND
L1 10mH Inductor PART#
R10 10K Linear Potentiometer PART#
R1 R5-R8 R14 1K 1/4 Watt Resistor PART#
R2 10K 1/4 Watt Resistor PART#
R3 R4 4K7 1/4 Watt Resistor PART#
R9 270R 1/4 Watt Resistor PART#
R11-R13 22K 1/4 Watt Resistor PART#
Q1-Q4 2N3904 NPN Transistor PART#
Y1 32.786 MHz Oscillator PART#
LED1 3mm Green LED PART#
ENC1 Digital Rotary Encoder PART#
J1 J5 J13-J15 2 Pin (1x2) .1 Header PART#
J2 10 Pin (1X10) .1 Header PART#
J3 J11 J12 6 Pin 1(x6) .1 Header PART#
J4 J9 10 Pin (2x5) .1 Header PART#
J10 8 Pin (1x8) .1 Header PART#
J6-J8 Terminal Block PART#
B1 Button Cell Battery Holder BH501-ND
DESIGNATOR PART NAME PART#
DESIGNATOR PART NAME PART#
DESIGNATOR PART NAME PART#
DESIGNATOR PART NAME PART#
DESIGNATOR PART NAME PART#
QTY
DESIGNATOR
VALUE/DESCRIPTION
PACKAGE
SUPPLIER
PART#
COST
TOTAL
1
D1
1N4007 1 Amp General Rectifier Diode
DO-41, Axial
DigiKey
1N4007-E3/54GICT-ND
 * .07
.70
2
D2, D3
1N4001 1 Amp General Rectifier Diode
DO-41, Axial
DigiKey
1N4001-E3/54GICT-ND
 * .07
 .70
4
D4-D7
1N4148 1 Amp General Rectifier Diode
DO-41, Axial
DigiKey
1N4148-TPMSCT-ND
* .06
.60
11
C1, C2 C4-C7, C9, C19, C13, C14
.1µF 50V Ceramic Disc Capacitor
.1 pitch
DigiKey
478-4276-1-ND
.39
3.90
11
C3
10pF Ceramic Disc Capacitor
.1 pitch
DigiKey
P12181-ND
* .54
5.40
2
C8, C12
470µF 50V Electrolytic Capacitor
Panasonic EEU-EB1H471 12.5mm dia x 5mm pitch radial
DigiKey
P13134-ND
.57
1.14
2
C11, C15
100µF 10V Electrolytic Capacitor
Panasonic EEU-EB1A101S 5mm dia x 2mm pitch radial
DigiKey
P13455-ND
.10
.20
1
U1
ET-AVR Stamp
Custom Footprint
www.futurlec.com
ETAVRSTAMP
19.90
19.90
1
U2
MAX3222CPN RS-232 3.3V-5V Transciever
DIP-18
DigiKey
MAX3222CPN+-ND
4.19
4.19
1
U3
SN74AHCT1G04DBVR Single Inverter Gate
SOT23-5
DigiKey
296-1112-1-ND
.40
.40
1
U4
WIZ810MJ
Custom
www.saelig.com
21.99
21.99
1
U5
DS1307 I2C Real Time Clock
DIP-8
DigiKey
DS1307+-ND
3.74
3.74
1
VR1
LM1084IT-3.3-ND 1A Low Dropout Voltage Regulator
T0-3B
DigiKey
LM1084IT-3.3-ND
3.13
3.13
1
VR2
LM1084IT-5.0-ND 1A Low Dropout Voltage Regulator
T0-3B
DigiKey
LM1084IT-5.0-ND
3.13
3.13
3
K1-K3
Tyco OMIH Series 5V SPDT 16A Relay
tYCO OMIH-SH-105L,394
DigiKey
PB1038-ND
2.26
6.78
1
L1
10mH Inductor
Axial .5
Digikey
PART#
COST
TOTAL
1
R10
10K Linear Taper Potentiometer
Panel Mount
DigiKey
PART#
COST
TOTAL
6
R1, R5-R8, R14
1K 1/4 Watt Resistor
Axial
DigiKey
PART#
COST
TOTAL
1
R2
10K 1/4 Watt Resistor
Axial
DigiKey
PART#
COST
TOTAL
2
R3, R4
4K7 1/4 Watt Resistor
Axial
DigiKey
PART#
COST
TOTAL
1
R9
270R 1/4 Watt Resistor
Axial
DigiKey
PART#
COST
TOTAL
3
R11-R13
22K 1/4 Watt Resistor
Axial
DigiKey
PART#
COST
TOTAL
4
Q1-Q4
2N3904 NPN General Purpose Transistor
TO-92
DigiKey
PART#
COST
TOTAL
1
Y1
32.786 MHz Crystal Oscillator
BCY-1
DigiKey
PART#
COST
TOTAL
1
LED1
3mm Green LED
.1 Pitch
DigiKey
PART#
COST
TOTAL
1
ENC1
Digital Rotary Encoder
PACKAGE
DigiKey
PART#
COST
TOTAL
5
J1, J5, J13-J15
2 Pin (1x2) .1 Header
PACKAGE
DigiKey

PART#

COST
TOTAL
1
J2
10 Pin (1X10) .1 Header
PACKAGE
DigiKey

PART#

COST
TOTAL
3
J3, J11, J12
6 Pin 1(x6) .1 Header
PACKAGE
DigiKey

PART#

COST
TOTAL
2
J4, J9
10 Pin (2x5) .1 Header
PACKAGE
DigiKey

PART#

COST
TOTAL
1
J10
8 Pin (1x8) .1 Header
PACKAGE
DigiKey

PART#

COST
TOTAL
3
J6-J8
Terminal Block
PACKAGE
DigiKey

PART#

COST
TOTAL
1
B1
Button Cell Battery Holder
PACKAGE
DigiKey

BH501-ND

1.14
1.14
QTY
DESIGNATOR
PART NAME
PACKAGE
DigiKey

PART#

COST
TOTAL
QTY
DESIGNATOR
PART NAME
PACKAGE
DigiKey

PART#

COST
TOTAL
QTY
DESIGNATOR
PART NAME
PACKAGE
DigiKey

PART#

COST
TOTAL
QTY
DESIGNATOR
PART NAME
PACKAGE
DigiKey

PART#

COST
TOTAL
QTY
DESIGNATOR
PART NAME
PACKAGE
DigiKey

PART#

COST

TOTAL


1 D1
2 D2, D3
4 D4-D7
2 J1, J5, J13-J15 2 Pin header
2 J4, J9 10 Pin (2x5) .1 Header
1 J10 8 pin .1 header
2 J3, J11, J12 6 pin .1 header
1 J2 10 pin .1 header
3 J6-J8 Terminal Block
1 B1 Button Cell battery Holder
11 C1-C7, C9, C10, C13, C14 Ceramic Disc
2 C8, C12 Electrolytic Capacitor 12.5mm dia x 5mm pitch radial
2 C11, C15 Electrolytic Capacitor 5.0mm dia x 2mm pitch radial
1 U5 DS1307 RTC 8 Pin DIP
1 R10 Linear Taper Potentiometer
1 U1 ET-AVR stamp
1 U2 MAX3222CPN DIP 18
1 U3 SN74AHCT1G04DBVR Single Inverter Gate SOT23-5
1 U4 Wiz810MJ
3 K1-K3 Relay
1 L1 Inductor
1 VR1 LM1084IT-3.3-ND
1 VR2 LM1084IT-5.0-ND
1 LED1 3mm Green LED
4 Q1-Q4 2N3904 NPN TO-92
1 Y1 32.786 MHz Crystal Oscillator
1 Digital Rotary Encoder  
6 R1, R5-R8, R14 1K
1 R2 10K
2 R3,R4 4K7
1 R9 270R
3 R11-R13 22K


I have ordered the latest revision of my PCB and will

 

Schematic 

To view the full size schematic, click the image below. You can also download an active PDF version of the schematics by clicking here.

Circuit Boards

I have ordered the latest revision of my PCB and will

 

Construction

I have ordered the latest revision of my PCB and will indow.

 

Need Help?

Now for the bad news. I posted this project for entertainment purposes and as a source of inspiration for those who like to read about and/or play with projects of this nature. I do not have the time, patience or resources to help people design, build, debug this porject or a derivative of this project. If you have questions keep them simple.   




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